# A Case of Colon Leiomyosarcoma Arising from the Muscularis Mucosae: A Case Report and Literature Review

## TL;DR

This paper reports a rare case of colon leiomyosarcoma originating from the muscularis mucosae and highlights its diagnosis and lack of recurrence after surgery.

## Contribution

The paper presents a rare case of primary colon leiomyosarcoma arising from the muscularis mucosae, contributing to its clinical and pathological understanding.

## Key findings

- The tumor was diagnosed as primary CLMS arising from the muscularis mucosa based on histological and immunohistochemical findings.
- The tumor had a clear border in the submucosa and was not connected to the muscularis propria.
- No recurrence was observed 24 months after laparoscopic surgery.

## Abstract

Colon leiomyosarcoma (CLMS) is an extremely rare neoplasm and the information regarding its clinical characteristics and specific treatment was still unclear.

A 73-year-old female who had been diagnosed with transverse CLMS underwent laparoscopic surgery. The resected specimen showed that the tumor contained proliferation of spindle-shaped cells and arranged in fascicular pattern, which was immunohistochemically positive for smooth muscle actin and desmin. Moreover, the tumor bottom was not continuous with the muscularis propria and had a clear border in the submucosa layer. According to these findings, we finally diagnosed it as primary CLMS arising from the muscularis mucosa (MM). No recurrence was noted 24 months after surgery.

This literature demonstrates CLMS arising from MM and suggests that its pathological diagnosis is associated with disease prognosis.