E2L30 Thyroid Tumors Pathoma

Question 1

Describe 131-I radioactive studies to assess thyroid masses

Answer 1

131-Iodine is taken up by cells in a ‘hot’ nodule in Grave’s disease and nodular goiter
Decreased uptake by ‘cold’ nodules warrants biopsy, often seen in adenoma and carcinoma

Question 2

How is the thyroid biopsied?

Answer 2

Fine Needle Aspiration

This is because the thyroid is very vascular and would otherwise bleed like crazy

Question 3

Describe the features of a follicular adenoma of the thyroid

Answer 3

Benign proliferation of follicles surrounded by a fibrous capsule.
Usually nonfunctional, but can secrete hormone

Question 4

What are the 4 types of thyroid carcinoma?

Answer 4

Papillary
Follicular
Medullary
Anaplastic
(Repeat these over and over in mind until memorized)

Question 5

Patients exposed to ionizing radiation early in life are at risk of developing what kind of thyroid carcinoma?

Answer 5

Papillary

Question 6

Describe features of a Papillary carcinoma of the thyroid

Answer 6

Most common thyroid carcinoma
Risk: exposure to ionizing radiation in childhood
Histo: finger-like papillae lined by cells with clear, “Orphan Annie Eye” nuclei and nuclear grooves, psammoma bodies
Often spreads to cervical lymph nodes but regardless, the prognosis is excellent

Question 7

Carcinomas classically like to metastasize through the lymph but there are 4 types that like to spread hematogenously. What are these 4 carcinomas?

Answer 7

Follicular Carcinoma of the Thyroid
Renal Cell Carcinoma
Hepatocellular Carcinoma
Choriocarcinoma

Question 8

What are the two thyroid neoplasms that invade local structures?

Answer 8

Reidel fibrosing thyroiditis

Anaplastic carcinoma

Question 9

What is the similarity and difference between follicular adenoma and carcinoma and how is this difference determined?

Answer 9

Both are surrounded by a capsule
Difference in that carcinoma penetrates the capsule
FNA cannot tell the difference between the two because it does no asses the capsule–must be examined entirely

Question 10

Describe follicular carcinoma

Answer 10

Malignant proliferation of follicular cells surrounded by capsule but capsule is penetrated
Spreads hematogenously (unique feature of this carcinoma)

Question 11

FNA of the thyroid produces malignant cells in an amyloid stroma. Diagnosis?

Answer 11

Medullary carcinoma

Question 12

What cells are malignant in a medullary carcinoma of the thyroid? What are the consequences of the secretions of these cells?

Answer 12

C cells which are the cells that produce calcitonin
High calcitonin causes hypocalcemia and can itself deposit in the gland as an amyloid
This is why it is classic to find malignant cells in an amyloid stroma with this cancer

Question 13

Describe the familial cases of thyroid medullary carcinoma and what must be considered when a familial case is suspected.

Answer 13

Familial cases are often due to multiple endocrine neoplasia–MEN 2A/2B which are associated with the RET oncogene
MEN 2A causes: medullary carcinoma, pheochromocytoma, parathyroid adenomas
MEN2B causes: medullary carcinoma, pheo, ganglioneuromas of the oral mucosa

Presence of the RET oncogene warrants prophylactic thyroidectomy

Question 14

Describe features of anaplastic carcinoma of the thyroid

Answer 14

Undifferentiated malignant tumor seen in the elderly
Similar to Reidel Fibrosing Thyroiditis in that it involves the surrounding tissue but different in that it is found in the elderly
Local invasion causes dysphagia, respiratory compromise
Poor prognosis