Lymph node metastasis of malignant peripheral nerve sheath tumor in the absence of widespread disease five years after diagnosis: a rare finding.

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue neoplasm that accounts for less than 10 percent of all soft tissue sarcomas. These tumors can arise spontaneously or in association with a neurofi-broma in patients with neurofibromatosis type I (NFI). Lymph node metastasis from MPNST is rarely seen and has only been reported in the setting of widespread metastasis. Therefore, regional lymph node dissections are not routinely performed in the management of MPNST. To our knowledge, this case is the first reported case of cutaneous MPNST metastatic to a regional lymph node in the absence of widespread disease. We report the case of a 49 year old male with a history of NFI and MPNST involving only the right elbow which was excised with clear margins. Five years later, he presented with an isolated 11.5 × 9.0 × 7.0 centimeter right axillary mass which was completely excised. Microscopic examination revealed metastatic MPNST with lymph node involvement. Although isolated lymph node metastasis from MPNST is rare, this case expands our knowledge of the clinical behavior of MPNST.