A Rare Case of Pancreatic Adenocarcinoma With Incidental Synchronous Hepatic and Sigmoid Colonic Metastasis: A Case Report and Literature Review

Abstract

Metastasis of pancreatic adenocarcinoma to the colon is a very rare condition that might be underdiagnosed and underreported in the literature. We report a very rare case of incidental findings of sigmoid metastasis secondary to pancreatic adenocarcinoma in a 60-year-old Saudi male, who is a non-smoker with a normal medical and surgical history. The patient presented to a primary care clinic with abdominal bloating and vague on/off abdominal pain for almost 1 year as well as unintentional weight loss without lower gastrointestinal (GI) symptoms. After the case was discussed in the multidisciplinary tumor board, the patient was started on systematic palliative chemotherapy. However, after receiving the first cycle, he started to deteriorate rapidly and succumbed to secondary cardiopulmonary arrest. Cases of synchronous metastasis of pancreatic adenocarcinoma to the colon might not be well known or common. However, a high index of suspicion and individualizing the workup tools may need to be used.

Keywords: cancer; liver metastasis; mass; pancreatic adenocarcinoma; sigmoid colon metastasis; tumor.

Figure 1. Abdomen CT scan

(a) A contrast-enhanced abdomen CT scan axial image showing an ill-defined non-enhancing low-density solid mass in the pancreatic body and tail (blue arrow). (b) A contrast-enhanced abdomen CT scan axial image showing liver metastases (blue arrows). (c) A contrast-enhanced pelvis CT scan axial image showing focal non-uniform wall thickening of the sigmoid colon (blue arrow). CT, computed tomography.

Figure 2. Colonoscopy

A colonoscopic view of the sigmoid colon showing a significant finding of an erythematous flat mucosa about 5 x 3 cm, which was found to be a metastatic pancreatic adenocarcinoma.

Figure 3. Histopathology of colonic lesion

(a, b) Sigmoid colon biopsy: colonic mucosa with underlying neoplastic, muscle infiltrative glands (H&E x4, x20). (c) Immunohistochemical stains showing a positive reaction to CK 7 in the infiltrative glands, while colonic mucosa is negative (CK 7 x 4). (d) Immunohistochemical stains showing a negative reaction to CK 20 in the infiltrative glands (CK20 x4).

Figure 4. Histopathology of pancreatic body lesion

(a) EUS-guided FNA: crowded and disoriented cells with variation in size, nuclear enlargement, and irregular nuclear membranes (PAP stain x40). (b) Cell block preparation: desmoplastic reaction around neoplastic glands (H&E stain x10). EUS, endoscopic ultrasound; FNA, fine-needle aspiration; PAP, Papanicolaou; H&E, hematoxylin and eosin.