Cytomorphology of pituitary carcinoma metastatic to liver diagnosed by fine-needle aspiration: A rare case report and review of literature.

Pituitary carcinomas (PCs) are rare entities constituting about 0.1-0.2% of all pituitary neoplasms. They are diagnosed by the presence of craniospinal or systemic metastasis in pituitary adenomas (PAs). The distant metastatic sites include liver, followed by bone, lung, and lymph nodes. The diagnosis of PC is rarely made on fine-needle aspiration cytology (FNAC) with only six cases reported till date; hence, the cytologic features are not well defined. Herein, we report a case of PA having high Ki-67 proliferation index and p53 expression, presenting with liver lesion 6 weeks post-surgery and diagnosed on FNA. Detailed cytomorphologic features are defined and compared. We emphasize that FNAC, along with clinic-radiologic correlation, is a cost-effective, safe, and diagnostically accurate method of diagnosing PC metastases.