MALIGNANT PERIPHERAL-NERVE SHEATH TUMORS (MALIGNANT SCHWANNOMAS) IN CHILDREN

We studied the clinical and pathologic features of 78 malignant peripheral nerve sheath tumors in children less-than-or-equal-to 15 years of age. There were 42 boys and 36 girls, with a median age of 10 years. The majority of the tumors (42, or 54%) were central or axial in location; the rest were peripheral. Sixteen patients (21%) had a history of von Recklinghausen's disease. Fourteen (18%) had a malignant peripheral nerve sheath tumor ar-ising in a nerve trunk or a neurofibroma and were unassociated with von Recklinghausen's disease. Patients typically presented with a painful mass of variable duration. Tumors ranged from 2 to 33 cm (median, 7.5 cm) and demonstrated a wide histologic spectrum that included spindled, epithelioid, and primitive neuroepithelial-like cells as well as heterologous elements (I 1). Immunohistochemical staining revealed S-100 protein in 28 of 50 cases (56%) as well as vimentin (13 of 21 cases, or 62%), Leu 7 (22 of 49 cases, or 45%), actin (eight of 20 cases, or 40%), and keratin (seven of 27 cases, or 26%). Survival status was known for 57 patients (73%). Kaplan-Meier estimates revealed a median survival of 45 months. Half of the patients had local recurrences at 12 months, and half had metastases at 24 months, most commonly to lungs, followed by lymph nodes, liver, bone, soft tissue, and brain. Age greater-than-or-equal-to 7 years, male sex, presence of von Recktinghausen's disease, central location, larger tumor size, and tumors with greater-than-or-equal-to 25% necrosis were found to be potentially significant adverse prognostic indicators by univariate analysis. Multivariate analysis revealed that larger tumor size, age greater-than-or-equal-to 7 years, tumor necrosis greater-than-or-equal-to 25%, and von Recklinghausen's disease to be independent adverse prognostic factors.