A case report of malignant transformation in neurofibromatosis type 1: pain and rapid growth as key indicators for early biopsy

Malignant peripheral nerve sheath tumor (MPNST) represents a life-threatening complication of neurofibromatosis type 1 (NF1). This report describes a male patient with NF1 and concomitant MPNST treated at our institution. A 55-year-old male first presented with multiple, skin-colored neoplasms distributed across his body over the course of three decades, without any identifiable predisposing factors. Two years before presentation, a firm subcutaneous nodule appeared on his left back, causing intermittent mild discomfort, leading to a diagnosis of multiple neurofibromas. Despite participation in a clinical trial, the lesion on his left back progressively enlarged, and associated pain intensified. A multidisciplinary team subsequently recommended resection of the dorsal mass via Mohs surgery under general anesthesia. Postoperative histopathological analysis confirmed NF1 with concurrent MPNST. No adjuvant targeted therapy was administered, and no recurrence was observed during the six-month follow-up. This case highlights the coexistence of NF1 and MPNST, aiming to enhance clinical awareness of the malignant transformation risks in NF1, thereby promoting earlier diagnosis and minimizing the potential for misdiagnosis and delayed intervention.