Introduction: Malignant Peripheral Nerve Sheath Tumor (MPNST) are aggressive soft tissue sarcoma (STS), originally arising from neural cell components. MPNST had a relatively high local recurrence rate of 22% and a disease survival rate of 45 - 60%. In this study, we would like to report a rare case of recurrent MPNST affecting the upper arm region, with a history of previously resected MPNST at the patient's ipsilateral elbow.
Case Presentation: A 38-years old male patient complained of an enlarging mass in his left anterior axilla Patient had a history of left elbow mass 2 years before and had resected twice. Eight months afterward, a new tumor grew from his left axilla. From the physical examination, the mass was fixated and firm with an oval shape, size 8 x 6 cm. From chest CT scan examination, it appeared a soft tissue mass surrounded with stranding fat had infiltrated his left teres major muscle. The mass was removed successfully and the pathology result revealed a grade 2 MPNST. Post-operative radiotherapy was then scheduled. Among many STS, MPNSTs are notorious for having a high recurrence rate. NF1 mutation, tumors deeper than fascia, large tumors, high-grade tumors, and tumors arising from the trunk, head, and neck are related to poor prognosis in MPNST. Surgeons' inadequate knowledge, unplanned resections, and their dependency on radiotherapy are other iatrogenic factors for recurrences.
Conclusion: MPNST has high recurrent risk, especially in high-grade tumors, large or deep tumors, surgery with positive resection margins, and NF1 mutations. The primary option for treatment is surgery and radiation therapy.