The microscopic picture in the needle biopsy was consistent with a serous microcystic adenoma (SMA) of the pancreas 1 2 3
and the pathological evaluation of the surgically resected tumor confirmed the diagnosis. Extensive sampling of the lesion revealed a multilocular cystic mass originating from the body and tail of the pancreas Figura_6
with no solid component. There was no cytologic atypia, mitotic activity, or necrosis. The cytoplasm of epithelial cells was rich in PAS-positive glycogen Figura_7
and lacked a mucin content. Immunohistochemically epithelial cells were reactive for EMA, cytokeratins 7 and 19, and unreactive for CEA Figura_7
, chromogranin A, synaptophysin, S100 protein, calretinin and CD10.
There are very few published reported cases of SMA which were investigated by needle biopsy the largest series including 11 cases 4
. Proper correlation with radiologic information is a key in making a correct diagnosis, as in the current case. In fact, based on the multicystic appearance of the tumor at CT-scan the differential diagnoses included a mucinous cystic neoplasm, a multilocular cystic renal cell carcinoma, a pancreatic lymphangioma, and the malignant counterpart of SMA, i.e. serous cystoadenocarcinoma. Mucinous cystic neoplasms of the pancreas show a different cell morphology (columnar cells with basally located nuclei, a clear cytoplasm containing mucin) and immunohistochemical evidence of CEA positivity. A multilocular cystic clear cell renal carcinoma growing as an apparently extrarenal tumor seemed a valid alternative hypothesis since this tumor may share several microscopic features with SMA 5
: in renal cell carcinoma, however, there is more significant nuclear atypia, the stromal septa contain at least focally collections of clear cells and, most importantly, tumor cells do not express CK7 and stain positively for CD10. The cuboidal morphology of cells and their immunohistochemical profile helped exclude a pancreatic lymphangioma. Finally, the serous cystoadenocarcinoma seemed to be a remote possibility due to the lack of any significant atypia or epithelial stratification.