# Acute Lumbar Pain Revealing a Rare Localization of a Primary Squamous Cell Carcinoma of the Psoas

## TL;DR

A rare case of squamous cell carcinoma in the psoas muscle was identified through acute lumbar pain and psoas abscess.

## Contribution

This case highlights a rare primary tumor localization in the psoas muscle, not associated with metastasis.

## Key findings

- The tumor was localized in the left psoas muscle without other tumor sites.
- The case was diagnosed through a combination of imaging and clinical evaluation.
- The report emphasizes the need for a precise therapeutic approach for psoas muscle tumors.

## Abstract

Damages to the psoas muscle are most often of infectious origin; other causes are observed, notably neoplasia and metastasis, hematomas, which sometimes pose a problem of care, especially in tumor-related conditions. Here, we report a rare case of psoas abscess associated with left pyonephrosis, revealing a squamous cell carcinoma of the left psoas without other tumor sites, along with the diagnostic and therapeutic approach taken in this case. This case report will make clinicians think about psoas muscle lesions, especially tumor lesions, which require a well-defined therapeutic approach.