Clinicopathological Features of Pancreatic Adenosquamous Carcinoma and Undifferentiated Carcinoma: A case series

Abstract

Adenosquamous carcinoma(ASqC) and undifferentiated carcinoma(UC) of the pancreas are rare, and thus we do not clearly know their biological characteristics. We therefore conducted a clinicopathological study of 17 patients with ASqC or UC to investigate their clinical features, imaging findings, histopathological findings of resected specimens, and prognostic factors. The subjects were 9 patients (11.1%) with ASqC and 8 (9.9%) with UC among 81 patients with invasive ductal carcinoma. Mean survival time was 16.3±5.0 months in the patients with ASqC and 12.4±5.6 months in those with UC. Analysis of prognostic factors revealed that survival was shorter in the patients with confluent multinodular type than in those with simple nodular type (5.0±2.4 vs. 18.4±4.8 months, P = 0.039) in patients with stage IVb rather than stage III or IVa cancer (6.2±2.9 vs. 19.4±5.2 months, P = 0.026). Survival tended to be slightly shorter in patients who had recurrence within 6 months. Histopathological findings of immunostaining revealed that all 17 patients were positive with CK7 (a marker for adenocarcinoma) in all 17 patients. ASqC and UC were suggested to be differentiated from adenocarcinoma. They are known to have a poorer outcome than common pancreatic cancer, but may be associated with a relatively good outcome in some patients.