Acinar Cell Carcinoma: A Rare Pancreatic Malignancy
A 35-year old male patient presented in out patient department, with complaints of diarrhea for last 2 years and pain upper abdomen for last 15 days. There were no other associated symptoms, co-morbidities and he was nonalcoholic and non-smoker. General physical examination revealed no abnormality, and on abdomen examination there was a firm, nontender, 8×8 cm retroperitoneal lump, with well-defined margins, in epigastrc region and also occupying part of left hypochondrial and umbilical region, with no organomegaly and no free fluid. Hematological, biochemical investigations and routine stool examination and Xray chest were normal. Ultrasonography of the abdomen showed a large 7.7×6.4×8.4 cm size heterogeneously hypoechoic mass, involving the body of pancreas, while the head of the pancreas, liver, spleen and other organs were normal. Contrast enhanced computed tomography showed a large, heterogeneously enhancing, well defined intrapancreatic lesion, of size 12×7.5 cm in body and tail region, with few small non-enhancing areas, indentation on posterior wall stomach, and loss of intervening fat plane (). There were no evidence of ascites, liver and peritoneal metastasis, and peripancreatic and retroperitoneal lymphadenopathy. Oesopha - gogastroduodenoscopy showed the presence of extrinsic impression on the posterior wall of gastric body. Colonoscopy and tumor marker CA 19-9 were normal. In view of a large mass involving the body of the pancreas and no evidence of metastasis, after adequate preoperative preparation, patient was taken up for surgery. Intra-operatively, there was a large mass of size 12×8 cm arising from the body and part of tail of pancreas, abutting splenic vessels and transverse mesocolon while pancreatic head was normal. The mass was free from stomach, transverse colon, duodenum and spleen (), and there were no palpable lymph nodes, liver and peritoneal metastasis and ascites. Distal pancreatectomy with splenectomy was done while the head of the pancreas was preserved. On histopathological examination, grossly, well circumscribed grey brown soft tissue mass measuring 12×8×8 cm, with multinodular external surface, and cut section was variegated with layers of hemorrhage and necrosis, and on microscopy, there was partly encapsulated tumor composed of cells arranged mainly in diffuse sheets, trabecular and focally in acinar pattern, at places tumor sheets are separated by thick fibrous septa and cells shows mild pleomorphism, round in shape, with indistinct cell membranes, moderate amount of granular eosinophilic cytoplasm, round to oval hyperchromatic nuclei (). Periodic acid-Schiff (PAS) staining with diastase showed granular cytoplasmic positivity (), and immunohistochemistry demonstrated acinar enzymes, trypsin and chymotrypsin. This histopathological picture was suggestive of acinar cell carcinoma of the pancreas. Post-operative period was uneventful and the patient received 6 cycles of chemotherapy (FOLFOX regimen) and got discharged on post-operative day 18.