Malignant transformation of neurofibromatosis-1 into low-grade malignant peripheral nerve sheath tumor: a case report.

Malignant Peripheral Nerve Sheath Tumor (MPNST) is a malignant mesenchymal tumor. The majority of MPNSTs are found in patients with neurofibromatosis type 1 (NF-1) who have a high-grade sarcoma. At the moment, there are just a few instances of low-grade MPNST caused by NF-1. We present a case of malignant transformation of NF-1 into low-grade MPNST in a patient with a long history of the disease. Multiple protruding masses with ulceration on the right shoulder and chest wall were discovered during physical examination. Complete tumor excision was done, followed by hematoxylin-eosin and immunohistochemical staining. A portion of the tumor had higher cellularity, hyperchromatic cell nuclei, and mitoses were seen in only five out of ten high-power fields. S-100 and vimentin were positive, whereas cytokeratin, desmin, SMA, and CD34 were negative. Ki-67 (MIB1) labeling index hot-spotting was around 25%. This was thought to be NF-1 malignant transformation into low-grade MPNST. Overall, knowing the clinical and pathologic characteristics of the disease, plus growing knowledge or experience with the condition, may improve preoperative diagnostic accuracy and extending survival time.