Background: Primary malignant peripheral nerve sheath tumors (MPNSTs) with a cutaneous or subcutaneous origin represent a small subset of MPNSTs thought to be derived from cutaneous neurofibromas or small peripheral nerves. Few cases of superficial MPNSTs originating from the skin have been reported in the literature.
Materials and methods: From October 1999 to February 2014, 13 patients were diagnosed with superficial or cutaneous MPNSTs and received treatment at Taipei Veterans General Hospital. Clinical data were collected via retrospective chart review. A retrospective study was performed to compare superficial and deep-seated lesions in terms of local recurrence, distal metastasis, and survival analysis. The relevant literature is also briefly reviewed.
Results: The most frequent initial symptoms were local swelling and pain. Ten tumors were found in the extremities, and 3 tumors were located on the trunk. All patients underwent surgery with curative intent. Four patients developed local recurrence, and 3 developed distant metastasis. Three of 13 patients died after a follow-up period of 11 to 180 months (mean, 53.4). Compared to deep-seated MPNSTs, superficial MPNSTs had a lower histopathological grading and better survival rate.
Conclusions: Superficial MPNSTs are a rare variant of MPNST. The relatively frequent lack of associated neurofibromatosis and superficial location within the dermis and subcutis may result in this entity being overlooked. According to our clinical experience, superficial MPNSTs might have better prognosis, but similar recurrence and metastasis rates compared with deep-seated lesions. Hence, awareness of this entity should prompt its consideration in the differential diagnosis of cutaneous sarcomas.