Immunocytochemical and ultrastructural findings in a case of rare carcinoma of the pancreas with predominance of malignant squamous cells in an intraoperative needle aspirate.

The cytologic diagnosis by intraoperative needle aspiration of a rare carcinoma of the pancreas composed predominantly of malignant squamous cells is reported. Both poorly differentiated and keratinized well-differentiated squamous cells were seen in the aspirate. Tissue for histologic confirmation was not obtained because of the position of the mass. Confirmatory ultrastructural and immunoperoxidase studies were thus done on the aspirated material to confirm the diagnosis.