Small Cell Carcinoma of the Pancreas: Primary or Metastatic?

Background Primary small cell carcinoma (SCC) of the pancreas is rare, approximately 35 cases reported in the literature. The aim of this study was to review a large center experience with SCC and determine whether the tumor was primary or metastatic. Methods In this retrospective correlation study, we reviewed electronic medical records and cytology and histology reports of all endoscopic ultrasonography–guided fine-needle aspiration of the pancreas between 2000 and 2010 to identify cases diagnosed as SCC of the pancreas. We determined if lesions were primary or metastatic based on patient history, imaging, and pathologic findings. Metastasis was considered when the patient concurrently or previously had a mass elsewhere as well as immunohistochemical stains supporting the tumor origin. Results Two thousand four hundred forty-five pancreatic fine-needle aspirations were identified during the study period (2000–2010). One hundred thirty-four of 2445 cases were endocrine neoplasms, with 8 patients (6%) identified as SCC (poorly differentiated endocrine carcinoma). Five patients had primary lung carcinoma, and 1 patient had primary cervical SCC, whereas a primary lesion could not be identified in the other 2. The prevalence of SCC was 1.5% of all endocrine neoplasms. Cytologic features and endocrine markers were diagnostic of SCC in all patients. All but 1 patient died, survival ranging from 5 to 32 months (median, 11 months) after the diagnosis. Conclusions Pancreatic SCC is rare and carries a grave prognosis. Most pancreatic SCCs are metastatic; therefore, search for the primary tumor is required, particularly given recent reports of good response of primary SCC to surgical resection.