Hypertrophied reversed palmaris longus muscle (pseudotumor) of the forearm causing median nerve compression: a case report

BACKGROUND: The palmaris longus muscle is considered one of the most anatomically variable muscles in the human body. Localized swelling of the forearm due to hypertrophy of the palmaris longus muscle is rare. CASE PRESENTATION: Here, we report a rare case of a 24-year-old Arab man who presented with a painful mass on his forearm with symptoms of median nerve compression. A full radiological assessment was performed, and he was treated conservatively. CONCLUSION: This case confirmed that a hypertrophied palmaris longus muscle can be the cause of swelling on the forearm and should always be considered in the differential diagnosis. With this report, we aimed to increase awareness regarding the unusual variations of palmaris longus muscle and the importance of using radiological investigations to establish a diagnosis.