Astrocytoma Imaging Findings
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This document provides information on astrocytoma neuroimaging and classification. It describes various types of astrocytomas including their cell of origin, common locations, histology, progression, and radiology characteristics. Key points covered include: - Astrocytomas include low-grade diffuse astrocytoma, anaplastic astrocytoma, and glioblastoma. - Radiology can show tumor infiltration and characteristics vary from non-enhancing to ring enhancement with necrosis. - Pathology examines features like cell type, mitoses, and staining for markers like GFAP.
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Astrocytoma Imaging Findings
- 1. Astrocytoma Neuroimaging Dr Deb
- 9. Astrocytoma of the Brain • Axial T2 weighted spin-echo image of the head. • There is an intra-axial mass in the left frontal lobe with surrounding vasogenic edema. • There is mass effect on the surrounding structures with compression of the left frontal horn and displacement of the falx to the right.
- 11. A 45 year old woman with a two year history of infrequent headaches presented with a seizure 4 years ago and was found to have a nonenhancing left posterior temporal and parietal lesion that was stereotactic biopsied and shown to be a low grade anaplastic astrocytoma grade 3. She was subsequently treated with radiotherapy, and later with chemotherapy. Despite treatment, the tumor recurred and radiosurgery was performed six months later. Six months following radiosurgery she developed visual field loss and speech problems. SPECT was normal. Several weeks following surgery, a MRI showed a questionable area of enhancement in the resection bed adjacent to the occipital horn.
- 13. Parietal lobe perfusion defect (HMPAO) with faint focal parietal thallium uptake, consistent with radiation necrosis.
- 22. Shown here is the displaced sensorimotor cortex of a patient with a low grade astrocytoma, demonstrated by fMRI
- 26. Three-dimensional mod of this patient's MRI was reconstructed. The brain is shown in white, the tumor is shown in green, the vessels are shown in red and the ventricles are shown in light blue.
- 27. This model helped visualize the lesion in 3D space. The location of the tumor was confirmed as being in the motor and primary sensory cortex. After discussion with the parents of the patient, it was decided to perform resection of the lesion under local anesthesia to monitor the patient's motor and sensory functions.
- 39. Glioblastoma
- 41. Admission scans after first seizure
- 42. One month later
- 43. Two months later
- 46. GBM
- 47. GBM Axial Gd Enhanced T1W MR Axial T2W MR
- 62. This coronal T1W Gadolinium enhanced MR shows a cerebellar mass with a "cyst with nodule" morphology.
- 64. JPA – WHO - 1 This is also a pathologically-proven JPA, presenting in a 14 y.o. boy. This one did not "read the book" and the mass, although partially cystic and partially solid, has a grossly heterogeneous morphology - rather than the classic "cyst with nodule" shape. A lesion with this complex configuration could be a malignant glioma with necrosis. However, the cerebellar location and the young age make JPA a more likely possibility.
- 79. With MRI criteria they all looked identical. One of them was removed using neuronavigation
- 80. An Ommaya reservoir was implanted. The patient recieved systemic chemotherapy with vincristin and carboplatinum, under which tumor nodules had not changed in size by the end of December 1998.
- 81. H&E sections of the tumor operated in 1994 showed a moderately cellular glial neoplasm. Some areas were composed of piloid astrocytes and displayed few Rosenthal fibers
- 82. Sometimes larger multinuclear cells were present
- 83. The regions near the ventricle were composed of loosely arranged piloid cells and large glial cells with one or more nuclei A broad glial fibrillary acidic protein (GFAP)-positive cytoplasm Areas immediately at the ventricle site ('V' in Fig. 3C and Fig. 3D ) showed five or six 'layers' of densely packed smaller astrocytic cells with shorter processes and only slight GFAP-immunoreaction. Mitoses, necroses and endothelial proliferations were absent.
- 84. The biopsy of one of the ventricular tumor disseminations in 1998 revealed histological and immunohistochemical features which were very similar with the initial resection specimen. The density of capillaries was however higher
- 85. The smaller neoplastic astrocytes which formed a 'layer' at the ventricle site were also demonstrable in the tumor spreadings (Fig. 8A). They could sometimes be found in the ventricular space without connection to the other tumor cells As in 1994, no histologic signs of anaplasia or malignancy could be found. Mitoses were absent. The Ki67-positivity was very low, especially in the densely packed cells in close vicinity to the ventricle (not shown). Cebrospinal fluid cytology revealed no anaplastic cells.
- 90. PLEOMORPHIC XANTHOASTROCYTOMA Axial T1W Gd Enhanced MR Axial CT
- 93. SUBEPENDYMAL GIANT CELL ASTROCYTOMA T1 Gd T1
- 94. Thank You
Editor's Notes
- Table 1: World Health Organization proposed new classification of CNS tumors I. Tumors of neuroepithelial tissue A. Astrocytic tumors Astrocytoma Variants: fibrillary, protoplasmic, gemistocytic, mixed Anaplastic (malignant) astrocytoma Glioblastoma Variants: giant cell glioblastoma, gliosarcoma Pilocytic astrocytoma Pleomorphic xanthoastrocytoma Subependymal giant cell astrocytoma B. Oligodendroglial tumors Oligodendroglioma Anaplastic (malignant) oligodendroglioma C. Ependymal tumors Ependymoma Variants: cellular papillary, epithelial, clear cell, mixed Anaplastic (malignant) ependymoma Myxopapillary ependymoma Subependymoma D. Mixed gliomas Mixed oligo-astrocytoma Anaplastic (malignant) oligo-astrocytoma Others E. Choroid plexus papilloma Choroid plexus papilloma Choroid plexus carcinoma F. Neuroepithelial tumors of uncertain origin Astroblastoma Polar spongioblastoma Gliomatosis cerebri G. Neuronal and mixed neuronal-glial tumors Gangliocytoma Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos) Desmoplastic infantile ganglioglioma Dysembryoplastic neuroepithelial tumor Ganglioglioma Anaplastic (malignant) ganglioglioma H. Pineal tumors Pineocytoma Pineoblastoma Mixed pineocytoma/pineoblastoma I. Embryonal tumors Medulloepithelioma Neuroblastoma Variant: ganglioneuroblastoma Ependymoblastoma Retinoblastoma Primitive neuroectodermal tumors (PNET) with multipotential differentiation - neuronal, astrocytic, ependymal, muscle, melanocytic, etc. a. Medulloblastoma Variants: desmoplastic, medullomyoblastoma, melanocytic medulloblastoma b. Cerebral (supratentorial) and spinal PNETs II. Tumors of cranial and spinal nerves Schwannoma (syn: neurilemmoma, neurinoma) Variants: cellular, plexiform, melanotic Neurofibroma Variants: circumscribed (solitary), plexiform, mixed neurofibroma/schwannoma Malignant peripheral nerve sheath tumor (MPNST)(syn: neurogenic sarcoma, anaplastic neurofibroma, malignant schwannoma ) Variants: epithelioid, MPNST with divergent mesenchymal and/or epithelial differentiation, melanotic III. Tumors of the meninges A. Tumors of meningothelial cells 1. Meningioma Histologic types: Meningothelial (syncytial) Transitional/mixed Fibrous (fibroblastic) Psammomatous Angiomatous Microcystic Secretory Clear cell Chordoid Lymphoplasmacyte-rich Metaplastic variants (xanthomatous, myxoid, osseous, chondroid) 2. Atypical meningioma 3. Anaplastic (malignant) meningioma Variants: of a-k above, papillary B. Mesenchymal, non-meningothelial tumors Benign: Osteocartilagenous tumors Lipoma Fibrous histiocytoma Others Malignant Mesenchymal chondrosarcoma Malignant fibrous histiocytoma Rhabdomyosarcoma Meningeal sarcomatosis Others C. Primary melanocytic lesions Diffuse melanosis Melanocytoma Malignant melanoma Variant: meningeal melanomatosis D. Tumors of uncertain origin Hemangiopericytoma Capillary hemangioblastoma IV. Hemopoietic neoplasms Malignant lymphomas Plasmacytoma Granulocytic sarcoma Others V. Germ cell tumors Germinoma Embryonal carcinoma Yolk sac tumor (endodermal sinus tumor) Choriocarcinoma Teratoma Variants: immature, teratoma with malignant transformation Mixed germ cell tumors VI. Cysts and tumor-like lesions Rathke's cleft cyst Epidermoid cyst Dermoid cyst Colloid cyst of the third ventricle Enterogenous cyst (syn: neuroenteric cyst) Neuroglial cyst Other cysts Lipoma Granular cell tumor (syn: choristoma, pituicytoma) Hypothalamic neuronal hamartoma Nasal glial heterotopias VII. Tumors of the anterior pituitary Pituitary adenoma Pituitary carcinoma VIII. Local extensions from regional tumors Craniopharyngioma Variants: adamantinomatous, squamous, papillary Paraganglioma (syn: chemodectoma) Chordoma Variant: chondroid chordoma Chondroma Chondrosarcoma Adenoid cystic carcinoma (syn: cylindroma) Others IX. Metastatic tumors
- A 45 year old woman with a two year history of infrequent headaches presented with a seizure 4 years ago and was found to have a nonenhancing left posterior temporal and parietal lesion that was stereotactic biopsied and shown to be a low grade anaplastic astrocytoma grade 3. She was subsequently treated with radiotherapy, and later with chemotherapy. Despite treatment, the tumor recurred and radiosurgery was performed six months later. Six months following radiosurgery she developed visual field loss and speech problems. SPECT was normal. Several weeks following surgery, a MRI showed a questionable area of enhancement in the resection bed adjacent to the occipital horn.
- Case #28: MRI, 8/31/92: Right temporal lobe astrocytoma CC: Episodic confusion HX: This 65 y/o RHM reportedly suffered a stroke on 1/17/92. He presented locally at that time with complaint of episodic confusion and memory loss lasting several minutes per episode. The "stroke" was reportedly verified on MRI scan dated 1/17/92. He was subsequently placed on ASA and DPH. He admitted that there had been short periods(1-2 days duration) since then, during which he had forgotten to take his DPH. However, even when he had been taking his DPH regularly, he continued to experience the spells mentioned above. He denied any associated tonic/clonic movement, incontinence, tongue-biting, HA, visual change, SOB, palpitation, weakness or numbness. The episodes of confusion and memory loss last 1-2 minutes in duration, and have been occurring 2-3 times per week. PMH: Bilateral Hearing Loss of unknown etiology, S/P bilateral ear surgery many years ago. MEDS: DPH and ASA SHX/FHX: 2-4 Beers/day. 1-2 packs of cigarettes per day. EXAM: BP 111/68, P 68BPM, 36.8C. Alert and Oriented to person, place and time, 30/30 on mini-mental status test, Speech fluent and without dysarthria. CN: Left superior quandranopia only. Motor: 5/5 strength throughout. Sensory: unremarkable except for mild decreased vibration sense in feet. Coordination: unremarkable. Gait and station testing were unremarkable. He was able to tandem walk without difficulty. Reflexes: 2+ and symmetric throughout. Flexor plantar responses bilaterally. LAB: Gen Screen, CBC, PT, PTT all WNL. DPH 4.6mcg/ml. Review of outside MRI Brain done 1/17/92 revealed decreased T1 and increased T2 signal in the Right temporal lobe involving the uncus and adjacent hippocampus. The area did not enhance with gadolinium contrast. CXR: 8/31/92: 5 x 6 mm spiculated opacity in apex right lung. EEG: 8/24/92: normal awake and asleep MRI Brain with/without contrast: 8/31/92: Decreased T1 and increased T2 signal in the right temporal lobe. The lesion increased in size and enhances more greatly when compared to the 1/17/92 MRI exam. There is also edema surrounding the affected area and associated mass effect. Neuropsychological testing: Low-average digit symbol substitution, mildly impaired verbal learning, and severely defective delayed recall. There was relative preservation of other cognitive functions. The findings were consistent with left mesiotemporal dysfunction. COURSE: Patient underwent right temporal lobectomy on 9/16/92 following initial treatment with Decadron. Pathologic analysis was consistent with a Grade 2 astrocytoma. GFAP staining positive. Following surgery he underwent 5040 cGy radiation therapy in 28 fractions to the tumor bed.
- Functional Magnetic Resonance Imaging is a relatively new addition to the brain imaging techniques which allows us to obtain information about brain function non invasively. Generally speaking, there are other MR techniques that also provide functional information. MR angiography displays macroscopic flow in brain arteries and veins, perfusion and diffusion imaging depict semiquantitative tissue perfusion estimates and maps of water diffusion coefficients, respectively, while MR spectroscopy detects specific metabolites and other substances present in brain parenchima. By fMR we mean a specific functional imaging approach targeting the correlate of neural activity associated with the most diverse mental processes. From simple motor, somatic sensory and parceptual function to complex patterns of motor learning, sensory discrimination, memory and attentional processes, this new way of looking at the human brain, still in its infancy, has already done immensurable contributions to our knowledge about it. Differently from Positron Emission Tomography (PET) or Single Photon Emission Tomography (SPECT), no tracer is needed. The intrinsic contrast of the blood is used instead. There exists a coupling between neuronal electrical activity and blood supply, which is mediated by some local vasodilating substances. Among them, nitric oxide (NO) figures as a high potency, fast acting one. Soon after neurons discharge, the local capillary bed receives a higher flow load, bathing the "activated" tissue. Contrary to one would expect, the oxigen contend of the local blood increases, due to a marked increase in delivered arterial blood and a hardly significant increase in oxigen extraction. The consequence is an increase in oxihemoglobin content as compared to deoxihemoglobin levels. What does in mean for imaging purposes? Deoxihemoglobin has paramagnetic properties, while oxihemoglobin is diamagnetic. In the MR context, this means that paramagnetic substances cause a substantial field inhomogeneity, causing loss of signal in the obtained images, what doesn't happen with diamagnet substances. In other words, regions of the brain containing higher oxigenated blood will appear slightly brighter. The problem is that this difference in signal intensity is extremely subtle, being undetectable by simply looking at the images. In order to discern the activated areas, multiple dynamic scans are obtained during alternating task and non-task periods. A statistical analisys is necessary do detect which pixels of the image show significant increase in signal correlated to the task periods. Finally, a coloured map of the activated regions is calculated and overlaid on high resolution images obtained in the same session from the same subject.
- This patient was operated under local anesthesia with IV sedation. The surgical navigation system previously described was used to detrmine the incision site for the skin flap and the craniotomy. Slight widening of the gyri could be observed at the site of the tumor but was not impressive. The surgical navigator was used to confirm the margins of the tumor at the surface, at which point, cortical stimulation was used to locate the motor and sensory cortices. Stimulation results revealed the lesion to be two gyri behind the motor cortex and that the tumor had indeed pushed the motor and sensory cortices forward. The lesion was totally removed grossly. Pathology results indicated the tumor to be a low-grade glioma. The patient tolerated the procedure extremely well and was discharged soon thereafter.
- Gross brain (left) and corresponding axial contrast-enhanced CT (right). Notice that the right hemisphere is grossly enlarged, but without a focal lesion. There is a diffuse infiltration of the right hemisphere by a low-grade (WHO Grade 2) fibrillary astrocytoma. This appearance is typical of the so-called "gliomatosis cerebri". Notice that although the right thalamus is slightly enlarged (displacement of the internal cerebral veins to left) there is no abnormal enhancement. A lack of enhancement is typical for low-grade diffuse astrocytomas.
- Genetic Profile of the Giant Cell Glioblastoma Aurelia Peraud, Kunihiko Watanabe, Karl Schwechheimer, Yasuhiro Yonekawa, Paul Kleihues, and Hiroko Ohgaki Giant cell glioblastoma is a rare glioblastoma variant characterized by the presence of large, bizarre, multinucleated giant cells. This glioblastoma subtype develops clinically de novo after a short clinical history and contains a high frequency of p53 mutations. In this study, we screened a series of 18 giant cell glioblastomas for additional genetic alterations. PCR-SSCP followed by DNA sequencing revealed PTEN mutations in 5 of 15 tumors (33%). Of these, two mutations were located in exon 5, two mutations in exon 6, and one mutation each in exons 1 and 9. Four mutations were point mutations and two mutations were deletions. One neoplasm contained two PTEN mutations (exons 5 and 6). None of the giant cell glioblastomas showed a homozygous deletion of PTEN or p16, or amplification of MDM2. Immunohistochemically, MDM2 overexpression was either not observed or detected in only a minor fraction of tumor cells. Differential PCR revealed EGFR amplification in only one of 17 tumors (6\%). These results indicate that giant cell glioblastomas occupy a hybrid position, sharing with primary (de novo) glioblastomas a short clinical history, the absence of a less malignant precursor lesion and a 30% frequency of PTEN mutations. With secondary glioblastomas that develop through progression from low-grade astrocytomas, they have in common a younger patient age at manifestation and a high frequency (>70%) of p53 mutations.
- Glioblastoma Multiforme Etiology: • The exact etiology is not known but has to do with several mutations in protooncogenes and tumor suppressor genes. • Some appear as a part of several hereditary syndromes such as neurofibromatosis or Turcot's syndrome. Pathogenesis: • The cause of the glioblastoma or any brain tumor is not known but changes or loss of chromosome 17 and inactivation of a tumor suppressor gene, p53, play a role. Thus far, we do not know what precipitates these changes. Epidemiology: • Glioblastomas are the most comman primary brain tumor. • They account for 50% of all gliomas and arise after age 50 in most patients. • Younger patients tend to have a better prognosis than the elderly. • Radiation and chemotherapy appear to extend the life of the patient. General Gross Description: • The glioblastoma multiforme has a multiform or variable appearance with evidence of old and recent hemorrhage (yellowish-brown to red), necrosis and areas of firm tissue. • Usually the glioblastoma is seen as a mass lesion involving a focal area although it may cross the corpus callosum to the other hemisphere or be multifocal. General Microscopic Description: • Microscopically the glioblastoma has many forms as well. • Is a highly cellular tumor with pleomorphic, basophilic nuclei with indistinct cytoplasmic borders or plump pink cytoplasm and a delicate fibrillary background. • Mitoses,necrosis, and capillary endothelial proliferation are common. Clinical Correlations: • The clinical appearance of the glioblastoma is typical for brain tumors in general with a slowly progressive neurological deficit of a focal nature, that is, a slowly progressive hemiparesis of one side of the body. • Prognosis is poor, in that, patients live only 6 month to a year after diagnosis. References: • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1342-1344. • Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp. 25-26. Synopsis by: M. L. Grunnet M.D.
- These images illustrate how one superficial GBM had an unusually early presentation as a small lesion. Because the tumor was a subcortical nodule, this mass caused and early presentation with seizures. The small ring-lesion had a rim of hemosiderin, and could mimic a benign process, such as an abscess or hematoma. However, an acute hematoma is usually not surrounded by vasogenic edema (as is seen surrounding this nodule), and an abscess usually does not have such a profound region of T2 shortening (hypointensity - the black rim). After a few months, the lesion had increased in size. Then, dramatically changed its morphology to present as a more "typical" heterogeneous multiloculated and ring enhancing mass on both MR and CT.
- Clinical History: 61-year-old RH white male with history of multiple CVAs with new onset of right sided hemiparesis of one week duration. Diagnosis: Bifrontal butterfly S-shaped lesion consistent with glioblastoma multiforme. Findings: Figure 1: Axial post Gadolinium T1 W1 of the brain reveals a large necrotic butterfly mass involving the corpus callosum with enhancing borders. There is no evidence of herniation. Discussion: A butterfly lesion is a lesion which infiltrates across the corpus callosum. Thus this pathological process spreads from one hemisphere to another. The differential diagnosis of a butterfly lesion includes: glioblastoma multiforme (GBM), lymphoma, and demyelinating process. In this patient's case, the diagnosis was that of a GBM. Symptoms can range from seizures to focal neurologic deficits to symptoms associated with increased intracranial pressure (headaches, nausea, vomiting, decreased visual acuity). Once a mass lesion is suspected, then an MRI with Gadolinium should be performed. This will usually show the classic ring enhancing (associated with angiogenesis occurring at the periphery of the tumor) lesion. However, definitive diagnosis is based on surgical biopsy. Astrocytomas are the most common primary cerebral tumors affecting those in their fifth and sixth decade of life. These tumors represent 50% of all primary intracranial neoplasms. On histologic basis, these tumors are graded as: Grade 1---> low grade, grade II ---> anaplastic, grade III---> GBM. Of all astrocytomas, greater than half are GBM which are the least differentiated and most aggressive. GBM tumors are treated with surgical resection and post-operative radiation. Nonetheless, this malignant process has a poor prognosis with the median survival being 8-10 months. The 1, 2, and 5-year survival rates are 30-44%, 8-12%, and 2.5-5%. The most common cause of death is reoccurrence of tumor at the original site. References: Grossman R, Loftus C. Principles of Neurosurgery . Lippincott-Raven, Philadelphia; 1999. Return to Neuro Imaging Page
- One of the most "classic" forms of GBM is the "butterfly glioma" illustrated here. Approximately 75% of glioblastomas will "go deep", and infiltrate into and through the corpus callosum, spreading from one hemisphere into the other. A butterfly lesion is a lesion which infiltrates across the corpus callosum. Thus this pathological process spreads from one hemisphere to another. The differential diagnosis of a butterfly lesion includes: glioblastoma multiforme (GBM), lymphoma, and demyelinating process. In this patient's case, the diagnosis was that of a GBM. Symptoms can range from seizures to focal neurologic deficits to symptoms associated with increased intracranial pressure (headaches, nausea, vomiting, decreased visual acuity). Once a mass lesion is suspected, then an MRI with Gadolinium should be performed. This will usually show the classic ring enhancing (associated with angiogenesis occurring at the periphery of the tumor) lesion. However, definitive diagnosis is based on surgical biopsy. Astrocytomas are the most common primary cerebral tumors affecting those in their fifth and sixth decade of life. These tumors represent 50% of all primary intracranial neoplasms. On histologic basis, these tumors are graded as: Grade 1---> low grade, grade II ---> anaplastic, grade III---> GBM. Of all astrocytomas, greater than half are GBM which are the least differentiated and most aggressive. GBM tumors are treated with surgical resection and post-operative radiation. Nonetheless, this malignant process has a poor prognosis with the median survival being 8-10 months. The 1, 2, and 5-year survival rates are 30-44%, 8-12%, and 2.5-5%. The most common cause of death is reoccurrence of tumor at the original site.
- WHO Grade IV Cell of Origin: ASTROCYTE Synonyms: GBM, glioblastoma multiforme, spongioblastoma multiforme Common Locations: cerebral hemispheres, occasionally elsewhere (brainstem, cerebellum, cord) Demographics: peak from 45-60 years Histology: grossly heterogeneous, degeneration, necrosis and hemorrhage are common Special Stains: GFAP varies, often present in areas of better differentiation Progression : Can't get any worse. Radiology: Glioblastoma is usually seen as a grossly heterogeneous mass. Ring enhancement surrounding a necrotic center is the most common presentation, but there may be multiple rings. Surrounding vasogenic edema can be impressive, and adds significantly to the mass effect. Signs of recent (methemoglobin) and remote (hemosiderin) hemorrhage are common. Despite it’s apparent demarcation on enhanced scans, the lesion may diffusely infiltrate into the brain, crossing the corpus callosum in 50-75% of cases.
- Case #101: MRI Brain, 1/26/1993: Pilocytic Astrocytoma in thalamus and caudate. CC: Headache. Hx: The patient is an 8y/o RHM with a 2 year history of early morning headaches (3:00-6:00AM) intermittently relieved by vomiting only. He had been evaluated 2 years ago and an EEG was "normal" then, but no brain imaging was performed. His headaches progressively worsened, especially in the past two months prior to this presentation. For 2 weeks prior to his 1/25/93 evaluation at UIHC, he would awake screaming. His parent spoke with a local physician who thought this might be due to irritability secondary to pinworms and Vermox was prescribed and arrangements were made for a neurologic evaluation. On the evening of 1/24/93 the patient awoke screaming and began to vomit. This was followed by a 10 min period of tonic-clonic type movements and postictal lethargy. He was taken to a local ER and a brain CT revealed an intracranial mass. He was given Decadron and Phenytoin and transferred to UIHC for further evaluation. MEDS: noted above. PMH: 1)Born at 37.5 weeks gestation by uncomplicated vaginal delivery to a G1P0 mother. Pregnancy complicated by vaginal bleeding at 7 months. Met developmental milestones without difficulty. 2) Frequent otitis media, now resolved. 3) Immunizations were "up to date." FHx: non-contributory. SHx: lives with biologic father and mother. No siblings. In 3rd grade (mainstream) and maintaining good marks in schools. EXAM: BP121/57mmHg HR103 RR16 36.9C MS: Sleepy, but cooperative. CN: EOM full and smooth. Advanced papilledema, OU. VFFTC. Pupils 4/4 decreasing to 2/2. Right lower facial weakness. Tongue midline upon protrusion. Corneal reflexes intact bilaterally. Motor: 5/5 strength. Slightly increased muscle on right side. Sensory. No deficit to PP/VIB noted. Coord: normal FNF, HKS and RAM, bilaterally. Station: Mild truncal ataxia. Tends to fall backward. Reflexes: BUE 2+/2+, Patellar 3/3, Ankles 3+/3+ with 6 beats of nonsustained clonus bilaterally. Gen exam: unremarkable. COURSE: The patient was continued on Dilantin 200mg qd and Decadron 5mg IV q6hrs. Brain MRI, 1/26/93, revealed a large mass lesion in the region of the left caudate nucleus and thalamus which was hyperintense on T2 weighted images. There were areas of cystic formation at its periphery. The mass appeared to enhance on post gadolinium images. there was associated white matter edema and compression of the left lateral ventricle, and midline shift to the right. There was no sign of uncal herniation. He underwent bilateral VP shunting on 1/26/93; and then, subtotal resection (left frontal craniotomy with excision of the left caudate and thalamus with creation of an opening in the septum pellucidum) on 1/28/93. He then received 5040cGy of radiation therapy in 28 fractions completed on 3/25/93. A 3/20/95 neuropsychological evaluation revealed low average intellect on the WISC-III. There were also signs of memory, attention, reading and spelling deficits; and mild right-sided motor incoordination and mood variability. He remained in mainstream classes at school, but his physical and cognitive performance began to deteriorate in 4/95. Neurosurgical evaluation in 4/95 noted increased right hemiplegia and right homonymous hemianopia. MRI revealed tumor progression and he was subsequently placed on Carboplatin/VP-16 (CG 9933 protocol chemotherapy, regimen A). He was last seen on 4/96 and was having difficulty in the 6th grade; he was also undergoing physical therapy for his right hemiplegia.
- The JPA is a WHO Grade I lesion. The mass is usually sharply circumscribed, with a very narrow zone of microscopic infiltration. The tumor nodule is supplied by capillaries that lack a complete blood-brain-barrier (BBB). The absence of the BBB is the cause of both the contrast enhancement, as well as the source of production of the proteinaceous fluid that accumulates in the "cyst". Because there is no true "lining" the lesions are not "true" cysts. The wall of tissue surrounding the fluid is normal or compressed brain, or may have a mild reactive (not neoplastic) gliosis.
- Histology: Alternating dense and loose areas, fusiform "piloid" bipolar astrocytes, microcysts in loose areas may coalesce to form the macroscopic cysts. The presence of nuclear atypia (without mitotic activity) does not convey a worse prognosis. Vascular changes are usually limited to capillary proliferations that may include glomeruloid capillaries and endothelial proliferation. Eosinophilic "Rosenthal fibers" are characteristic. Calcification possible.
- DISCUSSION: This neuropathologically rather unproblematic case is worth consideration for several reasons. First, it is an unusual finding that a histologically benign tumor is capable of widespread dissemination within the CNS. Second, this feature is unfamiliar to clinicians and even neuropathologists so that presentation of this case leads to a greater awareness of this phenomenon helping to avoid an unnecessary delay of treatment. Low-grade astrocytomas in children exhibit typically benign growth characteristics and have a good prognosis. In contrast to this, a small percentage of these tumors (4 %) manifest widespread dissemination either at presentation or later (2, 4, 5, 7). Astrocytomas with a predelection for cerebral spinal fluid seeding are lesions in close proximity to the ventricles and basal cisterns like in our case. In addition to a periventricular tumor location, operative manipulation has been suggested to play a role in tumor dissemination (5). In the recently published cases of childhood astrocytoma with widely distributed cerebrospinal fluid metastases, presence of tumor dissemination was detected at a presymptomatic stage using MRI as in our case. In such cases, cytologic examination of the cerebrospinal fluid failed to demonstrate the presence of malignant cells (7). As in our case the disseminated tumor nodules showed a strong and diffuse contrast medium enhancement. Because histology of these lesions lacked anaplastic features, enhancement was not interpreted as a sign of malignancy. It might, however, be due to high densities of blood vessels. Our case indeed demonstrated high vascularity in the seeding tissue but not in the initial specimen. The reason for the difference in blood vessel content is unknown. Also unknown are the factors which make benign astrocytomas capable to spread within the cerebrospinal fluid. Moreover, it is not clear whether this ability is restricted to particular neoplastic cell populations. Fig 8B shows aggregates of small tumor cells within the ventricle near the tumor surface but without connection to it suggesting that these cells might be the spreading cell population. They are identical to the cells which form the 'layers' at the ventricular site of the tumor ( Fig. 8A ). Whether these cells differ from the other neoplastic cells molecular genetically has not been determined at present. The prognosis for children with dissemination of a benign astrocytoma is considerably better than that for those with disseminated malignant gliomas (3). Although histological anaplasia is lacking, children have been treated aggressively with radiotherapy and chemotherapy with good response. Under this therapeutic strategy, metastases diminished in size or did not grow further (1, 2, 5, 6). One case in a four-year old girl, however, has been reported in which under chemotherapy and radiation no further growth of tumor spreadings was noted first, whereas later numerous confluent tumor masses developed. She eventually died of central circulatory failure (8). Until now, the patient presented here has showed no progression of disease under polychemotherapy. This case illustrates the importance of recognizing cerebrospinal fluid spread as a possible feature in benign juvenile astrocytomas, which does not inevitably mean a malignant course of the disease. In contrast, if the true benign histopathology of the metastases (or at least of one of the metastatic lesions) has been proven, prognosis is potentially good when treatment with radiation and/or chemotherapy is performed. However, cases with bad outcome have been described. REFERENCES Braun-Fischer A, Romeike BF, Eymann R, Glas B, Riesinger P, Reiche (1997) Pilocytic astrocytoma with subarachnoidal dissemination. Radiologe 38:899-904 Civitello LA, Packer RJ, Rorke LB, Siegal K, Sutton LN, Schut L (1988) Leptomeningeal dissemination of low-grade gliomas in childhood. Neurology 38:562-566 Grabb PA, Albright AL, Pang D (1992) Dissemination of supratentorial malignant gliomas via the cerebrospinal fluid in children. Neurosurgery 30:64-71 Kocks W, Kalff R, Reinhardt V, Grote W, Hilke J (1989) Spinal metastasis of pilocytic astrocytoma of the chiasma opticum. Child´s Nerv Syst 5:118-120 Obana WG, Cogen PH, Davis RL, Edwards MSB (1991) Metastatic juvenile pilocytic astrocytoma. J Neurosurg 75:972-975 Perez MJ, Lorenzo G, Munoz A, Otheo de Tejada E, Maldonado MS, Aparicio JM (1997) Low grade disseminated astrocytoma in childhood. Rev Neurol 25:877-881 Pollack IF, Hurtt M, Pang D, Albright AL (1994) Dissemination of low grade intracranial astrocytomas in children. Cancer 73:2869-2878 Romeike BFM, Niedermayer I, Braun-Fischer A, Graf N, Feiden W (1997) Pilocytic astrocytoma (PA) with subarachnoidal dissemination and „Fahr"-like calcifications after brain irradiation and polychemotherapy. Clin Neuropath 16:282-283 Contributed by Stephan Patt, Nils Haberland, Hagen Graupner, Dieter Schreiber and Rolf Kalff