15. 7 Thyroid Neoplasia Flashcards
In general, thyroid cancer presents as
a distinct solitary nodule
is a thyroid nodule more likely to be benign or malignant?
benign
Increased radioactive iodine (123) uptake (‘hot’ nodule) is seen in
Graves or nodular goiter
Decreased radioactive iodine (123) uptake (‘cold’ nodule) is seen in
adenoma and carcinoma (often warrants biopsy)
how do you biopsy a thyroid nodule?
fine needle aspiration
benign proliferation of follicles surrounded by a fibrous capsule; usually nonfunctional, but may secrete thyroid hormone
Follicular adenoma
Most common type of thyroid cancer
papillary carcinoma
major risk factor for thyroid papillary carcinoma
exposure to ionizing radiation
Histology of thyroid papillary carcinoma
PSAMMOMA BODIES & ORPHAN ANNIE EYES
comprised of papillae lined by cells with clear, “Orphan Annie eye” nuclei and nuclear grooves; papillae are often associated with psammomma bodies
prognosis of thyroid papillary carcinoma
excellent (10 year survival > 95% even though it often spreads to cervical lymph nodes)
to which lymph nodes does papillary thyroid carcinoma usually spread?
cervical
Malignant proliferation of follicles surrounded by a fibrous capsule with invasion through the capsule; the ENTIRE capsule must be examined microscopically to diagnose
Follicular carcinoma
Can diagnosis of thyroid follicular carcinoma be made with FNA?
NO! FNA only examines cells and not the capsule.
How does thyroid follicular carcinoma metastasize?
Hematogenously
Malignant proliferation of parafollicular C cells
medullary carcinoma
What are c cells?
neuroendocrine cells that secrete calcitonin
What does calcitonin do?
lowers serum calcium by increasing renal calcium excretion but is inactive at normal physiologic levels
high levels of calcitonin produced by medullary carcinoma may cause
hypocalcemia
calcitonin often deposits within thyroid medullary carcinoma tumor as
amyloid
thyroid medullary carcinoma on biopsy
sheets of malignant cells in an amyloid stroma
familial cases of thyroid medullary carcinoma as often due to
MEN2a and MEN2b
MEN2a and MEN2B are associated with mutations in the
RET oncogene
Detection of the RET mutation warrants
prophylactic thyroidectomy
undifferentiated malignant tumor of the thyroid usually seen in the elderly that often invades local structures, leading to dysphagia or respiratory compromise
anaplastic carcinoma
