A case of unsuspected peritoneal mesothelioma occurring with colonic adenocarcinoma masquerading as peritoneal metastases.

Wei Xie,Rishi A Patel,Linda K Green,Syeling Lai

doi:10.1155/2014/838506

Abstract

We report a case of synchronous primary colonic adenocarcinoma and malignant mesothelioma. A 61-year-old male presented with a six-month history of fatigue and weight loss. An abdominal computed tomography (CT) scan showed a 5.8 cm partially obstructing mass in the cecum with ascites and peritoneal thickening. A biopsy of the large mass showed an adenocarcinoma. Because the patient was clinically thought to be a T4 colon carcinoma with peritoneal metastatic lesions (M1), prior to initiating chemotherapy, a debulking right hemicolectomy was performed. Resection of the colon and ileum revealed a T3N0 colonic mucinous adenocarcinoma and concurrent diffuse malignant peritoneal mesothelioma. Presenting synchronous colonic and peritoneal mesothelial primary malignancies are exceedingly rare but must be considered to prevent incorrect clinical staging.

Highlights

There are 102,480 new cases of colon cancer diagnosed every year in the United States
50,830 patients die of colorectal cancer, accounting for 9% of all cancer death [1, 2]
We report a case of colonic adenocarcinoma and unsuspected concurrent primary peritoneal MM, with a detailed clinical, pathologic, and immunohistochemical study of this unusual malignancy coexistence

Summary

Introduction

There are 102,480 new cases of colon cancer diagnosed every year in the United States. 50,830 patients die of colorectal cancer, accounting for 9% of all cancer death [1, 2]. Peritoneal malignant mesothelioma (MM) is an extremely rare and aggressive tumor. Its incidence rates ranging between 0.5 and 3 cases per 1,000,000 males and between 0.2 and 2 cases per 1,000,000 females in developed countries [3, 4]. Synchronous colonic adenocarcinoma and coexistent primary MM in patients are extremely uncommon. We report a case of colonic adenocarcinoma and unsuspected concurrent primary peritoneal MM, with a detailed clinical, pathologic, and immunohistochemical study of this unusual malignancy coexistence. It is critical to keep in mind that colonic adenocarcinoma can present with coexisting peritoneal MM since the staging, surgical interventions and additional treatment modalities can differ tremendously

Case Report

Pathology

Discussion