All Sample Questions

Thyroid Disorder 1

Question

Vignette:

A 45-year-old woman comes to the clinic complaining of persistent fatigue, weight gain, and cold intolerance for the past few months. On physical examination, her skin is dry and coarse. Her heart rate is 60/min, and blood pressure is 140/90 mmHg. Blood work shows a high level of thyroid stimulating hormone (TSH) and a low level of free thyroxine (T4). Thyroid ultrasound shows a diffusely enlarged thyroid gland with a heterogenous appearance. Thyroid biopsy is performed. Which of the following is the most likely histological finding?

Choices

A. Colloid-filled follicles with flattened epithelium

B. Onion skinning of the arteries

C. Psammoma bodies

D. Thyroid follicles with Hurthle cells

E. Thyroid follicles with proliferating parafollicular C cells

Answer

D. Thyroid follicles with Hurthle cells

Explanation

This patient's symptoms, lab findings, and ultrasound results suggest Hashimoto's thyroiditis, a common cause of hypothyroidism. In Hashimoto's thyroiditis, the thyroid gland is diffusely enlarged and has a heterogenous appearance due to lymphocytic infiltration and fibrosis. The hallmark histological feature is the presence of Hurthle cells, which are enlarged follicular cells with abundant, granular, eosinophilic cytoplasm due to mitochondrial accumulation. These changes are reflective of chronic inflammation and destruction of the gland.

Colloid-filled follicles with flattened epithelium (choice A) are seen in endemic goiter due to iodine deficiency. Onion skinning of the arteries (choice B) is typical of malignant hypertension. Psammoma bodies (choice C) are a feature of papillary thyroid carcinoma. Thyroid follicles with proliferating parafollicular C cells (choice E) are seen in medullary thyroid carcinoma.