A Rare Case of Diffuse Extra‐Cranial Schwannomatosis of the Trunk and Limbs

ABSTRACT Schwannomas are benign peripheral nerve sheath tumors (PNSTs) arising from myelin sheaths, with schwannomatosis characterized by multiple lesions without neurofibromatosis type 1 (NF1) or type 2 (NF2) stigmata. Malignant transformation is rare but documented. We report a 44‐year‐old patient with multiple painful, slow‐growing recurrent masses in the right axilla, bilateral inguinal regions, and right lumbar area; these masses were initially noted early in 2017. Surgery was done with subsequent recurrence 6 years after initial diagnosis and surgery. Contrast‐enhanced CT scans done in 2023 revealed heterogeneously enhancing, well‐defined ovoid masses, some with spinal connections, consistent with schwannomas. Multiple biopsies of different sites at different time periods were consistent with histology that confirmed the diagnosis of schwannomatosis, with no NF1 or NF2 features. Histopathology results are attached. The patient underwent palliative 1st line chemotherapy with noted regression of some of the masses, though surgical resection remains the standard treatment. The last contact with the patient prior to writing this case was at the time of chemotherapy. This case highlights schwannomatosis as a rare, painful condition distinct from NF1 and NF2. CT imaging is vital in low‐resource settings for diagnosis, emphasizing the need for careful differentiation from other PNSTs due to distinct management and prognosis.