Hyaline cytoplasmic inclusions may be seen. Figure 12 Anaplastic selleck inhibitor carcinoma of the pancreas, displaying large, single and multinucleated cells (Pap stain, 400×) Differential diagnosis includes melanoma, hepatocellular carcinoma, pleomorphic sarcomas, poorly differentiated squamous cell carcinoma, and Hodgkin lymphoma. Adenosquamous carcinoma Comprise less than 5% of pancreatic neoplasms. There is a dual population of glandular and distinctly malignant squamous cells, rarely the squamous component may be predominant (Figure 13). Figure Inhibitors,research,lifescience,medical 13 Adenosquamous carcinoma, showing occasional squamoid tumor cells with orangeophilic

dense cytoplasm with distinct cell borders as well as glandular tumor cells with hypochromatic nuclei and prominent nucleoli (Pap stain, 400×) Smears show tumor cells with dense cytoplasm and distinct cell borders. Note focal squamous differentiation is not uncommon in ductal carcinomas. Connective tissue tumors Benign and malignant connective tissue tumors Inhibitors,research,lifescience,medical may rarely involve the pancreas. Metastatic tumors Metastatic tumors to the pancreas may include lung, kidney, breast, liver, GI, melanoma, prostate, sarcomas, myeloma, lymphoma

(primary rare) (Figure 14). Figure 14 Burkitt lymphoma obtained by endoscopic retrograde cholangiopancreatography (ERCP); note the characteristic lymphoma Inhibitors,research,lifescience,medical cells with vacuolated blue cytoplasm and background lymphoglandular bodies (DQ stain, 400×) Consider metastases if tumor cells are not typical of primary pancreatic carcinoma, particularly if there are small cells or squamous cells, and in cases

with known history of primary elsewhere. Ancillary studies should be performed. Ampullary carcinoma Ampullary carcinoma is similar to ductal type Inhibitors,research,lifescience,medical pancreatic carcinoma. Common bile duct Gallstones and stents may cause reactive cellular atypia. Tumors of the bile duct include granular cell tumor, cholangiocarcinoma, papillary bile duct neoplasms and embryonal rhabdomyosarcoma. Triage for ancillary studies Triage for ancillary studies requires on site evaluation and Inhibitors,research,lifescience,medical collection into appropriate media or fixatives. Tissue/cells may be collected for culture, special stains, immunochemistry, Megestrol Acetate flow cytometry (RPMI solution), electron micoscopy (glutaraldehyde), and molecular studies (RPMI). Also fluid may be submitted for amylase and CEA levels. Complications Pain, bleeding which is self limited, rarely requiring transfusion. Acute pancreatitis following aspiration cytology is rare and usually mild. There may be sepsis, following aspiration of a pseudocyst. Tumor seeding of needle track and peritoneal spread is extremely rare due to the smaller diameter of the aspirating needle (15,16). False negative diagnoses These are usually due to technical difficulties. There may be sampling errors or interpretive errors. Hypocellularity with lack of sufficient diagnostic cells may be due to small tumor size and desmoplasia. These may be minimized by on site evaluation of adequacy by pathology.