Answer: Anaplastic carcinoma of the pancreas

Histology: This pancreatic tumor contains marked pleomorphic cells, which show little morphologic evidence of epithelial differentiation in that they are widely separated from each other. The tumor cells have attracted a marked neutrophilic infiltrate around them, which keeps them separated. In the adjacent pancreas, a clue to the origin of these tumor cells is the presence of pancreatic intraepithelial neoplasia, in this case, grade 2 Pancreatic Intraepithelial Neoplasia. Immunohistochemistry helps confirm the epithelial nature of this tumor, as the tumor cells are immunoreactive for cytokeratin.

Discussion: Inflammatory malignant fibrous histiocytoma should not show diffuse labeling for cytokeratin, and typically would not primarily involve the pancreas. The marked neutrophilic infiltrate suggests an abscess, but the marked cytologic atypia of the cells within the lesion indicates that this is not a reactive process. Hodgkin’s Disease is a classic tumor that attracts prominent reactive inflammatory cells to it. However, in Hodgkin’s Disease, the inflammatory cells are predominantly eosinophils and lymphocytes, and Reed-Sternberg cells should not be immunoreactive for cytokeratin.

A subset of human cancers are associated with an intratumoral lymphocytic infiltrate. These tumors typically produce growth factors like G-CSF, which promote serum neutrophilia. In fact, this patient had a peripheral white count of 25,000 with 96% neutrophils. Carcinomas are the most common cancers to attract neutrophils, with the classic ones being Giant Cell carcinoma of the Lung, Anaplastic Pancreatic Carcinoma (such as this case), Anaplastic Thyroid Carcinoma, Sarcomatoid Renal Cell Carcinoma, and Adrenal Cortical Carcinoma. Aside from inflammatory MFH, Inflammatory Liposarcoma and Leiomyosarcoma may have prominent neutrophils. A neutrophil-rich variant of Anaplastic Large Cell Lymphoma has also been reported.