1. Endocrine Pathology, Case 2
The patient is a 42-year-old female who noticed a painless lump in her neck about a month ago. It has not seemed to increase or decrease in size.
A painless 3cm mass is palpated in the left neck. The mass moves when the patient swallows and seems contiguous with the thyroid gland. The remainder of the thyroid gland is normal.

2. Identify the organ
Describe the gross findings
What is the most probable diagnosis?

3. Thyroid Adenoma
The surgical specimen consists of a lobe of the thyroid gland
containing an adenoma. The adenoma is round, light brown, and
sharply demarcated from the deep red thyroid tissue.

4. Describe the histologic changes

5. A – adenoma
B – normal thyroid
C - capsule
Thyroid Adenoma
A microscopic section of thyroid gland reveals a follicular adenoma.
The neoplasm is composed of small follicles and is surrounded in part by a thin
fibrous capsule. The expanding neoplasm compresses the adjacent normal thyroid.

6. Follicular carinoma shows
How does one differentiate follicular carcinoma from follicular adenoma?
Follicular carinoma shows
evidence of capsular or blood vessel invasion or
B. documented metastases

7. Thyroid: Follicular carcinoma
A microscopic section of thyroid gland reveals a carcinoma
composed of well differentiated follicles.

8. A – blood vessel
wall
B - carcinoma
Thyroid: Follicular carcinoma
The microscopic section of thyroid gland reveals a follicular carcinoma.
The neoplasm is composed of follicles and invades the lumen of a blood vessel.
The wall of the vessel is highlighted by a special stain for elastic fibers (black).