Sarcomatoid Carcinoma of the Pancreas, an Immunohistochemical Study and Literature Review

Abstract

Sarcomatoid carcinoma of the pancreas is a rare and highly malignant variant of pancreas carcinoma that usually has a very poor prognosis. Because of its rapid progress, the therapeutic choices are limited. Only 10 cases of sarcomatoid carcinoma have been reported in the literature; therefore, little was known regarding its biological mechanism. We review the clinical history, radiological findings, and possible molecular mechanisms of the current case and the literature. Our case was a 65-year-old woman, presented with obstructive jaundice. CT revealed a 1.3 cm mass at the ampulla of vater without evidence of disease at other locations. A Whipple procedure was performed. Microscopically the carcinoma was infiltrative, poorly differentiated with signet ring cells and necrosis, invaded into perienteric adipose tissue, presented with perineural invasion, and metastasized into lymph nodes and omentum. Precancerous PanIN1 was identified in the pancreatic parenchyma. The tumor cells were positive for cytokeratin, CDX2, MUC1, and P53. The immunohistochemistry profiles were compared with the literature; these tumors were usually positive for cytokeratin, MUC1, and CA19-9. Several molecular pathways had been documented in this rare entity. Loss of E-cadherin was identified in 87% of the cases. The resulting disruption of cell adhesion might be an early event that could contribute to its aggressive behavior; KRAS and P53 mutation also have been detected that could result in its rapid proliferation. Furthermore, the increased TGFβ1 might regulate the transition from epithelial to mesenchymal morphology. These molecular pathways were discussed in detail. Increased awareness and recognition of this rare entity and understanding its molecular mechanisms allow for the correct diagnosis and prompt initiation of specific therapies.