ABSTRACT
Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine neoplasm of the skin that has a high propensity to metastasize. Abdominal metastases of MCC have been described previously though these are typically regional with nodal spread. We report the case of a 60-year-old man with a history of left upper extremity MCC who had resection, radiation therapy, and immunotherapy. He ultimately developed large bowel obstruction from metastatic intraperitoneal implants. A 6 cm mass at the descending colon was biopsied and proven to be metastatic MCC. The tumor eroded through the wall of the colon and perforated, requiring emergent colectomy for septic shock. Herein, we describe the first case of colonic perforation secondary to metastatic MCC. This case illustrates the importance of expedient and multifactorial management of patients with rapidly growing metastatic colonic tumors that are at risk for perforation.
ABSTRACT
INTRODUCTION: Incidence of peritoneal carcinomatosis (PC) after curative resection of stage II and III colon cancer varies widely. Although certain features are considered high risk for PC, the impact of these features on PC incidence is unclear. METHODS: A retrospective analysis was performed on patients ≥ 18 years old with resected stage II and III colonic adenocarcinoma treated at two academic institutions from 2007 to 2018. Clinicopathologic features, treatment and outcomes data were recorded. Patients with reported high-risk features (pT3N0-2 with mucinous/signet ring components, pT4, pN1c, perforation) were identified. The remaining stage II and III patients were used for comparison. RESULTS: Of 219 eligible patients, 93/219 (42.5%) were stage II and 126/219 (57.5%) were stage III. Median follow-up time was 25 (1-146) months. Adjuvant systemic treatment was administered to 133/219 (60.7%) patients. Overall incidence of PC was 14/219 (6.4%) and the median time to PC was 18 (1-37) months. The high-risk and comparison groups contained 113 and 106 patients, respectively. Incidence of PC was significantly different between groups (high-risk 9.7% vs comparison 2.8%, p = 0.04). Median time to PC was not significantly different between the groups [high-risk 17 (1-37) months vs comparison 20 (7-36) months, p = 0.88]. CONCLUSION: Overall PC incidence in patients with resected stage II and III colon cancer was 6.4%. Although the high-risk group developed PC at a significantly higher rate, the rate of PC in this group was still below 10%. The results of this study represent real-world rates of PC and should be taken into account when designing future studies.
