Colonic Infiltration By A Metastatic Malignant Peripheral Nerve Sheet Tumor Arising In The Lower Limb

A 74-year-old man presented a mass located in the left leg near the knee which was characterized as a malignant peripheral nerve sheet tumor (MPNST). Multiple lung lesions and a 5-cm mass in the caecum were detected by Computed Tomography. This appearance was equivocal. By colonoscopy and related biopsies colonic infiltration by sarcoma cells was detected. In this case, a primitive MPNST and bowel metastasis were diagnosed. Given the relative rare tumor it is difficult to estimate the incidence of bowel metastasis, but secondary bowel involvement in MPNST must be taken into consideration in presence of suggestive radiographic images and/or clinical symptoms (bleeding and anemia).