Thyroid Cancer - Practice Question
A 36-year-old woman presents with a painless thyroid nodule that she noticed two months ago. She has no history of radiation exposure and no family history of thyroid disease. On physical exam, a 1.8 cm firm, non-tender nodule is palpated in the right lobe of the thyroid. Ultrasound reveals a hypoechoic solid nodule with microcalcifications and irregular borders. Fine needle aspiration biopsy is performed, and cytology shows large polygonal cells with overlapping nuclei that appear empty with finely dispersed chromatin and nuclear grooves.
Which of the following histologic findings is most characteristic of this patient’s diagnosis?
A) Sheets of pleomorphic giant cells with necrosis and mitotic figures
B) Lamellated calcified structures surrounded by tumor cells
C) Amyloid deposition within the stroma with positive Congo red staining
D) Uniform cells forming microfollicles invading through a capsule
E) Eosinophilic cells with abundant granular cytoplasm and prominent nucleoli
See the comments below for the answers!
Answer to question 1:
Correct Answer:
Papillary thyroid carcinoma
Explanation:
This patient has classic findings of papillary thyroid carcinoma, the most common thyroid malignancy. The "Orphan Annie eye" nuclei—so named because they appear empty due to dispersed chromatin—are a hallmark histologic feature. Other associated findings include nuclear grooves, intranuclear pseudoinclusions, and psammoma bodies. PTC often presents as a painless thyroid nodule and can be suggested by concerning ultrasound features such as microcalcifications and irregular margins.
A) Medullary thyroid carcinoma is associated with calcitonin secretion, amyloid stroma, and neuroendocrine features.
B) Follicular thyroid carcinoma shows capsular and vascular invasion, but lacks Orphan Annie nuclei.
D) Anaplastic thyroid carcinoma is highly aggressive and histologically undifferentiated.
E) Hurthle cell carcinoma shows large eosinophilic cells with abundant granular cytoplasm.
Answer to question 2:
Correct Answer:
Lamellated calcified structures surrounded by tumor cells
Explanation:
This patient has papillary thyroid carcinoma, confirmed by cytologic findings including:
- Nuclear grooves
- Intranuclear cytoplasmic inclusions
- Psammoma bodies (concentrically laminated calcifications)
Although Orphan Annie eye nuclei are a hallmark feature, psammoma bodies and nuclear inclusions are equally important and also commonly tested.
A) Describes anaplastic thyroid carcinoma
C) Describes medullary thyroid carcinoma
D) Suggests follicular carcinoma, which is diagnosed based on capsular or vascular invasion
E) Refers to Hurthle cell (oncocytic) carcinoma