Clinicopathological features and surgical outcomes of adenosquamous carcinoma of the pancreas: a retrospective analysis of patients with resectable stage tumors

Purpose Adenosquamous carcinoma of the pancreas is a rare subtype of pancreatic cancer. We herein describe the clinicopathological features of surgically resected cases of adenosquamous carcinoma of the pancreas. Methods From 2001 to 2011, 132 patients underwent R0 resection for Stage IIA or IIB pancreatic cancer. The survival rate, pathological features and recurrence status were reviewed. Results Out of 132 patients, 121 patients had tubular adenocarcinoma, and only seven had adenosquamous carcinoma (ASC). The incidence of ASC increased with the tumor size. The overall survival and disease-free survival periods of the patients with ASC were significantly shorter than those of patients with tubular adenocarcinoma (p = 0.0153 and p = 0.0045). The histological findings revealed more marked venous invasion in ASC compared to tubular adenocarcinoma (G1, G2 and G3). The proportion of v3 cases, which denotes the most severe venous invasion, was 31.3 % in G1, 47.3 % in G2, 60.0 % in G3 and 71.4 % in ASC cases, respectively. Other factors, including lymphatic and nerve invasion, were not correlated with the histological subtypes. The incidence of ASC was 11.1 % in the tumors more than 6 cm in diameter, and 0 % in those less than 2 cm in diameter. Conclusions We revealed that adenosquamous carcinoma of the pancreas is associated with a poor outcome, and also clarified its clinicopathological features.