Cutaneous and Subcutaneous Perineuriomas in 2 Pediatric Patients
Perineuriomas are rare benign peripheral nerve sheath tumors that can present in a variety of locations with varying histologic patterns, most commonly in young to middle-aged adults; they are particularly rare in the pediatric population. Perineuriomas have a distinctive constellation of morphologic, immunohistochemical, and ultrastructural characteristics that allows for distinction from other benign peripheral nerve sheath tumors. We present 2 cases of perineuriomas that arose as cutaneous lesions in children.
Practice Points
- Perineuriomas are rare benign peripheral nerve sheath tumors that most commonly occur in young to middle-aged adults but rarely can present in children.
- Immunohistochemically, perineuriomas show positive staining with epithelial membrane antigen, GLUT1, claudin-1, and frequently with CD34; they are negative for S-100 and glial fibrillary acidic protein.
- Perineuriomas should be considered in the differential diagnosis in children who present with a well-circumscribed nodular lesion in the subcutaneous tissue.
Management—Perineuriomas are considered benign. The presence of mitotic figures, pleomorphism, and degenerative nuclear atypia akin to ancient change, as seen in ancient schwannoma, does not affect their benign clinical behavior. Treatment of a perineurioma typically is surgical excision with conservative margins and minimal chance of recurrence.1,11 So-called malignant perineuriomas are better classified as MPNSTs with perineural differentiation or perineurial MPNST. They also are positive for EMA and may be distinguished from perineurioma by the presence of major atypia and an infiltrative growth pattern.17,18
Considerations in the Pediatric Population—Few pediatric soft tissue perineuriomas have been reported. A clinicopathologic analysis by Hornick and Fletcher1 of patients with soft tissue perineurioma showed that only 6 of 81 patients were younger than 20 years. The youngest reported case of perineurioma occurred as an extraneural perineurioma on the scalp in an infant.19 Only 1 soft tissue perineural MPNST has been reported in the pediatric population, arising on the face of an 11-year-old boy. In a case series of 11 pediatric perineuriomas, including extraneural and intraneural, there was no evidence of recurrence or metastasis at follow-up.4
Conclusion
Perineuriomas are rare benign peripheral nerve sheath tumors with unique histologic and immunohistochemical features. Soft tissue perineuriomas in the pediatric population are an important diagnostic consideration, especially for the pediatrician or dermatologist when encountering a well-circumscribed nodular soft tissue lesion of the extremity or when encountering a neural-appearing tumor in the subcutaneous tissue.
Acknowledgment—We would like to thank Christopher Fletcher, MD (Boston, Massachusetts), for his expertise in outside consultation for patient 1.
