Pseudotumorous pancreatitis.

Chronic pancreatitis can occasionally present as a focal, noncalcified mass, indistinguishable from carcinoma. Radiologic studies in 21 such patients were considered to show carcinoma in 16 and an islet cell tumor in 5 patients. Seventeen of the patients came to laparotomy when a palpable mass was found in each; 9 of the patients had a partial pancreatectomy, and multiple biopsy specimens were taken in 8 patients. Four patients did not come to surgery; in them the diagnosis was based on examination of percutaneous biopsy specimens and follow-up. In all patients the histologic diagnosis was chronic relapsing pancreatitis.