Fungating malignant peripheral nerve sheath tumor arising from a slow-growing mass in the forearm: a case report and review of the literature

Abstract

Background: Malignant peripheral nerve sheath tumor is a rare and aggressive form of sarcoma that arises from a peripheral nerve, mostly in association with neurofibromatosis type 1. Half of the cases were reported in the extremities, with the lungs being the most common site of metastasis. We report a rare case of successful limb salvage surgery performed for a large exophytic malignant peripheral nerve sheath tumor of the right forearm with wide surgical margins followed by split-thickness skin graft and later a flexor carpi radialis tendon transfer to extensor digitorum communis tendon.

Case presentation: A 51-year-old Bedouin Arabic man presented to our institution with an incompletely excised, large, fungating, malignant peripheral nerve sheath tumor occupying most of his right forearm. Staging imaging showed multiple lung nodules. He underwent wide local excision followed by skin graft and tendon transfer as a palliative measure to preserve the function of his dominant limb. The operation was performed without any complications, and the patient had an excellent postoperative result. Afterward, he was started on multiple lines of chemotherapy that failed because of disease progression, and the patient died 7 months after the operation.

Conclusion: Clinicians must consider the possibility of soft tissue sarcoma even in a patient with a small, slow-growing, superficial mass. Furthermore, a wrong open biopsy or nononcological surgical procedure may lead to possible contamination and ultimately a more radical procedure than would have originally been necessary, where this can be prevented by an early referral to a highly specialized sarcoma center.

Keywords: Forearm; Malignant peripheral nerve sheath tumor; Sarcoma.

Fig. 1

Preoperative photo taken of the fungating tumor after isolating the forearm in preparation for sterile draping. Blood can be seen oozing from the tumor

Fig. 2

a Magnetic resonance imaging (MRI) of the forearm. Axial T1-weighted image shows infiltrative subcutaneous mass involving the proximal ulnar aspect with skin defect and slightly hyperintense signal IIA3. b MRI of the forearm. Axial T1-weighted fat-saturated postcontrast image shows significant enhancement with internal necrosis IIA1. c MRI of the forearm. Sagittal T1-weighted fat-saturated postcontrast material infusion IIA2

Fig. 3

Computed tomographic scan of the chest in transaxial view with lung window showing multiple lung nodules that most likely correlate with metastatic disease

Fig. 4

Intraoperative photo showing complete en bloc resection of the mass with a safety margin from the extensor digitorum communis muscle

Fig. 5

Intraoperative photo showing muscle approximation that was done to cover the exposed tendon, as well as an approximation of the skin using the purse-string technique

Fig. 6

Microscopic examination of the tumor. a There is a proliferation of spindle cells with abundant mitotic figures. b Heterologous elements in the form of osteoid are seen, laid directly by the tumor cells. c Palisading necrosis is identified. All images are stained with hematoxylin and eosin. Original magnification × 40

Fig. 7

Right forearm photo taken in the clinic 1 month after the operation, showing completely healed and well-taken graft with the elbow in full extension