Primary Multiple Malignant Peripheral Nerve Sheath Tumors with Hematogenous and Lymphatic Metastases in Neurofibromatosis Type 1: A Case Report

Introduction. Malignant peripheral nerve sheath tumor (MPNST) is a neuroectodermal sarcoma with an incidence of 5−9 %. Approximately 25−50 % of MPNST cases are associated with neurofibromatosis type 1 (NF1). Case Description. A patient presented to the Oncology Research Institute at the Tomsk National Medical Research Center in 2009 with a painless mass on the posterior right thigh. Diagnostic evaluation confirmed a grade 2 MPNST of the soft tissues. The patient underwent wide local excision with intraoperative radiation therapy (12 Gy). Clinical findings — including multiple neurofibromas along the sciatic nerve and café-au-lait spots — established a diagnosis of NF1. Local recurrence occurred three years postoperatively, requiringre-excision with IORT (15 Gy). In 2014, a solitary lung metastasis was resected via atypical lower lobectomy, followed by adjuvant chemotherapy. One year later, the patient presented with gastric bleeding secondary to a new tumor, requiring gastrectomy with D2 lymphadenectomy. Histopathological examination revealed a multinodular conglomerate extensively involving the gastric wall with serosal extension (without adjacent organ invasion) and metastatic perigastric lymph node involvement, consistent with metachronous grade 3 MPNST with metastatic involvement of one lymph node. Disease progression manifested as peritoneal metastases and ascites in January 2016, leading to patient mortality two months later. Conclusion. MPNST associated with NF1 represents a rare, highly aggressive malignancy with poor prognosis. Key characteristics include high local recurrence rates and metastatic potential via both hematogenous and lymphatic pathways.

malignant peripheral nerve sheath tumor, MPNST, neurofibromatosis type 1, NF1, lymphatic metastasis