Pancreatic cancer metastasis to the rectum detected on colonoscopy

Surgical resection of hepatic and rectal metastases of pancreatic acinar cell carcinoma (PACC): a case report

Background

Pancreatic acinar cell carcinoma (PACC), a rare variant of pancreatic malignancy, is generally managed the same way as pancreatic ductal adenocarcinoma (PDAC). Surgical resection is the gateway to curing it; however, once it metastasizes (usually to the liver, lungs, lymph nodes, or peritoneal cavity), systemic chemotherapy has been the only option, but with unfavorable results.

Case presentation

A 67-year-old man with symptoms of loss of appetite and weight underwent surgery for malignancy of the pancreatic tail extending into the entire pancreas. The pathological diagnosis was PACC following total pancreatectomy. Twenty-four months after the pancreatectomy, a solitary liver metastasis was treated by partial hepatectomy, and, subsequently, 4 months later, he presented with melena. Further examination revealed a type-2 rectal tumor. Histological examination following biopsy revealed it to be rectal metastasis of PACC, and it was treated by abdominoperineal resection. Subsequently, the patient did not have tumor recurrence as of 40 months after pancreatectomy.

Conclusions

This is a rare case of PACC presenting with metachronal metastases in the liver and rectum, and we successfully treated them by surgical resections. Since the malignant behavior of PACC is usually less than that of PDAC, surgical resection could be an option even for metastatic lesions when the number and extent of metastases are limited.

Colonic and anal metastases from pancreato-biliary malignancies

Pancreato-biliary malignancies often present with locally advanced or metastatic disease. Surgery is the mainstay of treatment although less than 20% of tumours are suitable for resection at presentation. Common sites for metastases are liver, lungs, lymph nodes and peritoneal cavity. Metastatic disease carries poor prognosis, with median survival of less than 3 mo. We report two cases where metastases from pancreato-biliary cancers were identified in the colon and anal canal. In both cases specific immunohistochemical staining was utilised in the diagnosis. In the first case, the presenting complaint was obstructive jaundice due to an ampullary tumour for which a pancreato-duodenectomy was carried out. However, the patient re-presented 4 wk later with an atypical anal fissure which was found to be metastatic deposit from the primary ampullary adenocarcinoma. In the second case, the patient presented with obstructive jaundice due to a biliary stricture. Subsequent imaging revealed sigmoid thickening, which was confirmed to be a metastatic deposit. Distal colonic and anorectal metastases from pancreato-biliary cancers are rare and can masquerade as primary colorectal tumours. The key to the diagnosis is the specific immunohistochemical profile of the intestinal lesion biopsies.