Three cases of unusual solid pseudopapillary tumors. Can radiology and histology aid decision-making?

CONTEXT Solid pseudopapillary tumors of the pancreas are generally considered to be of low malignant potential despite their often large size at presentation. The diagnosis of a solid pseudopapillary tumor depends on the characteristic histomorphology supported by immunohistochemistry. The tendency of some of these tumors to be locally aggressive and also to metastasize has been well recognized. It is not possible to predict the biologic behavior of these tumors based only on their morphology. METHODS The hospital database including the radiological records and histopathology of patients with metastatic solid pseudopapillary tumors, treated at the Tata Memorial Hospital between January 2006 and May 2007 were retrospectively reviewed. RESULTS The clinical details, radiological features and histopathology of three cases of unusually aggressive solid pseudopapillary tumors are presented. CONCLUSIONS It is important to recognize that solid pseudopapillary tumors may present or recur as locally invasive as well as widely metastatic lesions. While clinical presentation and radiology demonstrate an aggressive disease, it may still be difficult to prove its malignant potential on conventional histomorphological grounds. In spite of the presence of local invasion and metastasis, long term survival is possible and complete excision should be attempted.