Cellular peripheral neural tumors (neurofibromas) in children and adolescents: A clinicopathological and immunohistochemical study

Nine examples of a cellular peripheral neural tumor (CPNT) were identified in a review of 139 peripheral nerve sheath neoplasms in children, which included 60 neurofibromas and 16 malignant peripheral nerve sheath tumors. The mean age at diagnosis of these nine patients was 7 years, with six presenting in the first decade of life and four were noted at birth. The male:female ratio was 0.5. Topographically, the tumors were located in the extremities, 4; head and neck, 3; and trunk, 2. One or another stigmata of von Recklinghausen's neurofibromatosis (VRN) was present in four patients. After initial resection, seven children remained well, but two developed a recurrence; the histology was identical to the original tumor in one case but overt malignant transformation had occurred in the second. This case was the only tumor-related death in this series. The CPN as a circumscribed but nonencapsulated mass measuring 1.8-7.5 cm in greatest dimension in the subcutaneous and deep soft tissues and had a compact spindle cell pattern, occasional mitoses, and minor foci of typical neurofibroma. Immunohistochemical staining revealed vimentin expression in all seven cases, Leu-7 in six, myelin basic protein and S-100 protein in five, desmin in one, and actin in none. In contrast to neurofibroma and malignant peripheral nerve sheath tumors, CPNT tended to occur earlier, either congenitally or in the first decade, and slightly more commonly in females. The anatomical distribution and pattern of immunoreactivity were similar to neurofibroma. However, the cellularity and mitotic activity of these neoplasms were sufficiently disquieting as to raise concerns about the prognosis, and in one case, the tumor behaved in an unequivocally malignant fashion. When a peripheral neural tumor with the pathologic features described in this study is encountered, wide excision and careful clinical follow-up are recommended..