Abstract
Background : Solid-growth type solid-pseudopapillary neoplasms (sSPNs) are extremely rare. While a precise elucidation of the cytological features is important for a proper disgnosis, there have been only a few published reports of sSPNs. Herein, we report the cyto-immunocytochemical features of sSPNs in comparison with those of pancreatic neuroendocrine tumors (PNETs).
Case : A 16-year-old woman was admitted with complaints of abdominal pain. An abdominal CT and MRI revealed a lesion measuring 25×15 mm in the tail of the pancreas, and distal pancreatectomy was performed. Imprint cytology of the tumor revealed tumor cells in small loose clusters or scattered as single cells in a background of hemorrhage. There was no clear evidence of formation of a pseudo-papillary pattern. Macroscopically, the lesion was a solid tumor, and microscopically, nest-growth type proliferation of the tumor cells was observed, without clear formation of a pseudo-papillary pattern. Comparison of the cytopathological findings between sSPN and PNET revealed that the chromatin pattern was different between sSPNs and PNETs, with the latter showing salt and pepper chromatin pattern. Immunohistochemical analysis (IHC) of the sSPN revealed positive staining for vimentin and CD10, but negative staining for synaptophysin and chromogranin A.
Conclusion : We suggest that examination of the chromatin pattern and IHC examination to determine the expression patterns of vimentin, CD10, synaptophysin and chromogranin A are important and critical for accurate diagnosis of sSPNs.
