Answer: Atypical epithelial cells suspicious for papillary thyroid carcinoma

Histology: The specimen is scant with rare fragments consisting of pleomorphic cells with enlarged nuclei and rare intranuclear inclusions having a sharp rim of condensed chromatin. Cytoplasmic features are occasionally squamoid. Papanicolaou stained smears are acellular and non-contributory.

Discussion: While there are features (particularly the nuclear inclusions) that raise the possibility of papillary thyroid carcinoma, a metastasis from the patient’s known renal cell carcinoma cannot be excluded. Nuclear features of RCC can vary widely depending on the grade of the tumor, and given the scant nature of this aspirate, a definitive diagnosis cannot be made. However, subsequent total thyroidectomy revealed a papillary thyroid carcinoma.