Thyroid, Papillary carcinoma

Papillary thyroid carcinoma (PTC) is the most common type of thyroid malignancy, with strong female predominance (~4:1). Frozen sections of the thyroid gland are rarely done; the diagnosis of PTC is generally available to surgeons with thyroid fine needle aspirates usually being done prior to the surgery.

The diagnosis is heavily reliant on the cytological features, and the characteristic nuclear features are expected to be present in the majority of the tumour cells. These nuclear features include: 1) nuclear crowding, with frequent overlapping, 2) powdery, ground-glass ("orphan Annie") nuclei, 3) abundant nuclear grooves, and 4) nuclear pseudoinclusions. Mitoses are scanty or absent. On histology, as the name suggests, papillary patterns can certainly be seen, but various other architectural patterns can be seen in PTC, and multiple patterns can be observed in a single tumour.