2. Definition
• A discrete swelling in an otherwise impalpable
gland is termed solitary thyroid nodule.
3. • Prevalence - 3-4% of adult population.
• Female : Male – 4:1
• Importance of STN lies in the risk of malignancy
compared with other thyroid swellings. (10 –15%
of STN are malignant.)
4. CONDITIONS PRESENTING AS
SOLITARY THYROID NODULE
• Dominant nodule of a multinodular goitre.
• Thyroid adenoma
• Thyroid cyst
• Thyroid carcinoma
• Localised form of thyroiditis,colloid goitre
5. Work up of a STN-History
Age and gender- Children (Child with a thyroid
nodule – 50% chance of it being malignant )
- Men > 50yrs
Exposure to radiation for Hodgkin’s / Ca Breast
35yrs after exposure,
7-10% of exposed patients.
100 Rads- Thyroid nodules
Thyroid carcinoma
>2000 Rads - Prevent thyroid neoplasm
(Thyroid gland destroyed)
Rapid nodule growth
Pain, Hoarseness, Compressive symptoms
6. History-Contd.
• History for specific endocrine disorders-medullary
carcinoma,MEN type2
• Family h/o thyroid carcinoma
7. Examination
• Firm, irregular texture with fixation.
• Enlarged cervical nodes – Papillary cancer
8. Lab. Evaluation
• Thyroid function test ( T3,T4,TSH )- To identify
patients with unsuspected hyperthyroid states and
dictate appropriate workup.
• Serum calcitonin level-Medullary carcinoma is
strongly suspected.
• Detection of thyroid autoantibodies in patients
with toxic features.(anti microsomal and anti
thyroglobulin antibodies)
9. Ultrasound
• Nature of the swelling (Solid or cystic) –cystic
lesions are usually but not always benign.
• To detect nodules of a MNG which are not
clinically palpable.
• To detect lymph nodes.
• Follow up of patients who are managed
conservatively to detect increased volume of a
suspicious lesion.
10.
11. Thyroid scan
• Using Iodine131 or Technetium-pertechnetate
99m.
• On scanning swellings are categorised as hot
(overactive),warm(active) or cold(underactive)
• Not useful in distinguishing benign and malignant
lesions since majority of cold nodules are benign
(80%) and some warm nodules are malignant
(5%)
• Only indication is in patients with toxic features to
differentiate Toxic adenoma (rest of the gland is
suppressed) from toxic MNG.
13. FNAC
• Single most useful investigation which can detect most
of the conditions.
• A specimen is considered adequate if at least six
properly prepared smears contain 15-20 groups of well
preserved clumps of follicular epithelium.
• Can diagnose colloid nodules,thyroiditis,papillary
carcinoma,medullary carcinoma,anaplastic carcinoma
and lymphoma.
• Cannot distinguish between a follicular adenoma and
carcinoma.
• Follicular cells in FNAC - 6-20% chance of malignancy.
• Sensitivity –89%
14. • Specificity-91%.
• False negative rate-1-6%. Hence benign nodules
diagnosed by FNAC should be followed
sequentially with ultrasound to make sure the
characteristics do not change.
• FNAC results – benign,suspicious or malignant.
• Suspicious lesions increased incidence of
malignancy.
16. Epithelial cells in a follicular arrangement
suggesting adenoma, but which could be
from a follicular carcinoma
17. Hashimoto's thyroiditis. A, Group of Hürthle cells, with
large cytoplasm and prominent nuclei, surrounded by a
teratogeneous population of lymphocytes. B,
Hypercellular aspirate with lymphocytes and Hürthle cells.
18. Epithelial cells in a papillary formation from a
papillary thyroid carcinoma. Nuclear grooves
are also apparent.
19. Treatment
• FNAC suggestive of colloid nodule – if not
otherwise suspicious can be followed up (USG
every 6 months to document stability of nodule
size)
• Thyroid suppression not superior to observation in
these patients and risk of osteoporosis is high if
thyroid hormone suppression is given to
postmenopausal females.
20. Indications for surgery in STN
• Neoplasia :FNAC positive or clinically
suspicious-age,male sex,hard
texture,fixity,recurrent laryngeal nerve
palsy,lymphadenopathy,recurrent cyst
• Toxic adenoma
• Pressure symptoms
• Cosmesis
21. • Toxic adenoma – Radioiodine and surgery
(lobectomy) are equally effective.
• FNAC shows follicular cells surgery is
indicated(6-20% chance of malignancy).
Type of surgery :
• Hemithyroidectomy +/- intraop frozen section for
suspicious lesions
• Near total thyroidectomy if FNAC is suggestive of
malignancy.
• Subtotal thyroidectomy if STN is a dominant
nodule of MNG.
22.
23. Thyroid cysts
• 15-20% of thyroid lesions are cystic lesions
• Usually benign and result from an ischemic
episode leading to tissue necrosis and liquefaction
of a nodule.
• About 25% of papillary thyroid carcinomas
undergo necrosis and appear partially cystic by
USG.
• Presence of solid areas within cyst suggest
malignancy.
24. Treatment
• Aspiration of cyst is usually curative
Indications for surgery :
• Recurrent cyst
• Malignant cytology in cyst fluid
• Hemorrhagic fluid
• Residual swelling after aspiration
• Large cyst (size >4cm)
