# A Case Report of Metastatic Melanoma in the Transverse Colon

## TL;DR

This case report describes a rare instance of melanoma spreading to the colon and the complications from immunotherapy treatment.

## Contribution

The novelty lies in highlighting a rare metastatic site and the serious side effect of immunotherapy in a melanoma patient.

## Key findings

- Melanoma can metastasize to the transverse colon, often without symptoms.
- Immunotherapy can cause severe adverse events like gastrointestinal perforation.
- Careful monitoring and risk assessment are crucial for melanoma patients on immunotherapy.

## Abstract

Colonic metastasis from melanoma is extremely rare and is often asymptomatic, complicating detection. Diagnosis requires imaging and endoscopic evaluation. Treatment typically involves surgical resection with systemic therapies like immunotherapy and targeted therapy. However, immunotherapy has increased immune-related adverse events, including gastrointestinal perforation, a rare but serious complication. This report details a case of a Caucasian male patient in his 60s with a history of excised scalp melanoma eight years prior, who developed metastatic melanoma in the transverse colon. After initiating combination immunotherapy with ipilimumab/nivolumab, he suffered a bowel perforation, necessitating palliative care. The case underscores the need for vigilant monitoring for asymptomatic gastrointestinal tract metastases in melanoma patients and careful risk assessment when considering immunotherapy. It emphasizes the challenge of balancing aggressive treatment with managing potentially severe adverse events.