Samia Amar, Boutaina Essaher, Manal Oufroukhi, Youssef Omor, Rachida Latib, Hatim Essaber
Journal: Medpeer Publisher
ISSN: 3066-2737
Volume: 3
Issue: 8
Date of Publication: 2026/08/26
Skeletal muscle metastasis from colorectal adenocarcinoma is an exceptionally rare manifestation of metastatic disease. We report the case of a 60-year-old woman with a history of moderately differentiated colonic adenocarcinoma who developed a new lesion within the left rectus abdominis muscle during oncological follow-up. The lesion was absent on a computed tomography (CT) examination performed 9 months earlier and became apparent on a subsequent contrast-enhanced CT examination, during which the patient's overall disease had also progressed. Targeted ultrasonography subsequently demonstrated a well-defined, oval, predominantly hypoechoic intramuscular lesion, confirming its localization in the left rectus abdominis muscle. In the context of the known colorectal malignancy, interval disease progression, and new appearance of an enhancing intramuscular lesion, the findings were considered highly suggestive of skeletal muscle metastasis. No biopsy was performed, and the lesion was considered a radiologically presumed skeletal muscle metastasis based on the clinical and context. This case highlights the importance of comparing current and prior CT examinations and demonstrates the complementary role of ultrasound in confirming the intramuscular origin of an unusual metastatic lesion.
Skeletal muscle metastasis, Colorectal cancer, Rectus abdominis, Intramuscular metastasis
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