A Case of a Metastatic Disease to the Pancreas from a Small-Cell Lung Carcinoma Documented by a CT-Scan-Guided Trucut Biopsy: The Diagnostic Role of Cytomorphology and Immunohistochemistry

Unlike primary pancreatic carcinoma, metastatic lesions of the pancreas are uncommon and account for approximately 2% of pancreatic malignancies. Small-cell lung carcinoma (SCLC) represents a group of highly malignant tumors giving rise to early and widespread metastasis at the time of diagnosis. However, the pancreas is a relatively infrequent site of metastasis by this neoplasm, and reports on metastatic small-cell carcinoma (SCC) in the pancreas, either of pulmonary or extrapulmonary origin, to be diagnosed by CT-scan-guided trucut biopsy (CT-TCB) are very rare. A 56-year-old man presented with a laterocervical lymphadenopathy associated to a mixed-density lung mass and a mass in the pancreatic body. CT-TCB slides from the pancreatic mass contained small, round tumor cells with extensive nuclear molding. The cytomorphological and histological diagnosis was metastatic SCC. Immunocytochemical staining showed that a variable number of neoplastic cells were positive for cytokeratin 7, TTF1, chromogranin A, and synaptophysin but negative for leukocyte common antigen and cytokeratin 20 with a very high expression of KI67. The transbronchial needle biopsy confirmed the diagnosis of an SCC. This case represents a rare metastatic lesion in the pancreas from SCLC, diagnosed by CT-TCB histological and immunohistochemical studies.