A 33-year-old woman presents with a swelling in her neck, which she first noticed 2 months ago. Physical examination reveals a solitary, nontender nodule of the thyroid gland measuring 2 cm in diameter. Thyroid function tests are within normal limits. The nodule does not accumulate 125Iodine on thyroid scintiscan. A biopsy of the nodule is shown in the image. Which of the following is the most likely diagnosis?
Medullary thyroid carcinoma
Answer : A Follicular adenoma
A single, well circumscribed, thyroid nodule in a young patient most likely represents a follicular adenoma, which refers to a benign neoplasm that exhibits follicular differentiation.
It is the most common tumor of the thyroid and typically presents in euthyroid persons as a solitary “cold” nodule (i.e., a tumor that does
not take up radiolabeled iodine).
Follicular adenoma is an encapsulated neoplasm in which the cells are arranged in follicles normal thyroid tissue.
The other choices do not typically present as an isolated small nodule, but a biopsy is necessary to rule out other causes. In this case, the biopsy demonstrates a benign proliferation of thyroid follicles