GLI1, CDK4, and MDM2 Co‐Amplification Gastric Plexiform Fibromyxoma: A Case Report and Literature Review

ABSTRACT Plexiform fibromyxoma (PF) is a rare mesenchymal tumor that primarily occurs in gastric origin with a benign behavior. PF commonly harbors the MALAT1::GLI1 fusion gene. Here, we describe a case of a 36‐year‐old female with a PF. Abdominal computed tomography (CT) showed a 3.3 cm mass in the stomach. She underwent laparoscopic partial gastrectomy. Immunohistochemistry (IHC) of the tumor revealed strongly positive staining for CD34 , SDHB , STAT6 , MDM2 , and CDK4 . And the tumor showed TP53 mutant expression. Next‐generation sequencing (NGS) comprehensive genomic profiling identified GLI1 , CDK4 , and MDM2 co‐amplification and TP53 mutations. Here, we first report a case of a young woman with a PF harboring co‐amplification of GLI1 , CDK4 , and MDM2 genes. The patient underwent complete removal of the tumor without the use of radiotherapy or chemotherapy. No recurrence was observed during the follow‐up period of 8 months. This study aims to improve our understanding of PF by analyzing the clinicopathological characteristics of this case, including immunohistochemical (IHC) and genetic examination, and reviewing relevant literature.