Soft Tissue Perineurioma in a Patient With Neurofibromatosis Type 2: A Tumor not Previously Associated With the NF2 Syndrome
Neoplasms that commonly affect patients with neurofibromatosis type 2 (NF2) include schwannomas, meningiomas, astrocytomas, ependymomas, and neurofibromas. Perineuriomas are rare tumors of the peripheral nerve sheath that share some characteristics with meningioma. As in both NF2-associated and sporadic cases of schwannoma and meningioma, perineuriomas often harbor mutations or deletions of the NF2 gene. However, perineuriomas have not previously been reported in the clinical setting of NF2. A 30-year-old man with a history of bilateral vestibular schwannomas, a parasagittal meningioma, an intraspinal ependymoma, and multiple other neoplasms involving both cranial and peripheral nerves (thereby fulfilling the diagnostic criteria for NF2) presented with an enlarging thigh mass. The diagnosis of cellular soft tissue perineurioma was confirmed by both immunohistochemical and ultrastructural analysis. This case represents the first report of a soft tissue perineurioma arising in the setting of NF2.
[Show abstract] [Hide abstract] ABSTRACT: Perineuriomas are composed of differentiated perineurial cells. Perineuriomas have been recently recognized by the immunoreactivity for epithelial membrane antigen (EMA). Microscopically, perineuriomas show proliferation of spindle cells with wavy nuclei and delicate elongated bipolar cytoplasmic processes. The tumor cells are usually negative for the S-100 protein. Ultrastructurally, perineurial cells reveal slender, nontapered processes containing pinocytic vesicles and discontinuous basal lamina. Interestingly, hybrid tumors of benign peripheral nerve sheath tumor (PNST) have been recently reported by using immunohistochemical and ultrastructural investigations. Herein, we report a case of soft tissue perineurioma arising in the skin of a 56-year-old female; another case of a hybrid tumor of perineurioma and schwannoma in the posterior mediastinum occurred in a 53-year-old male, which is the first case of the hybrid PNST tumor reported in Korea.0Comments 7Citations
- "Although the tumors are not associated with neurofibromatosis type 1 or 2, a case of soft tissue perineurioma in a patient with neurofibromatosis type 2 has been reported.3 Additionally, some studies have described that fluorescence in situ hybridization and molecular analysis demonstrate deletions or point mutations on the chromosome 22q11 in the region of the NF2 gene and chromosome 10. "
- [Show abstract] [Hide abstract] ABSTRACT: Peripheral nerves consist of 3 layers with differing characteristics: the endoneurium, perineurium, and epineurium. The perineurium represents a continuum with the pia-arachnoid from the central nervous system and extends distally with the sheath of capsular cells of peripheral sensorial organs and propioceptive receptors. It is made of layers of flattened cells surrounded by a basement membrane and collagen fibers, forming concentrically laminated structures around single nerve fascicles. Functionally, the perineurium modulates external stretching forces (that could be potentially harmful for nerve fibers), and along with endoneurial vessels, forms the blood-nerve barrier. Multiple pathologic conditions associated with the perineurium have been described. Perineurial invasion is considered an important prognostic factor in several malignant neoplasms. Perineuriomas are true benign infrequent perineurial cell neoplasms that have been divided in 2 categories: those with intraneural localization and a more common extraneural (soft tissue) group, including sclerosing and reticular variants. Sporadic cases of malignant perineuromas have been reported. Interestingly, neurofibromas and malignant peripheral nerve sheath tumors may also display perineurial cell differentiation. The histologic appearance of perineuriomas may overlap with other soft tissue spindle cell neoplasms. Immunohistochemistry is imperative for the diagnosis, although in certain cases ultrastructural studies may be needed. Typical perineuriomas are positive for epithelial membrane antigen, glucose transporter-1-1, and claudin-1, and negative for S-100 protein and neurofilaments. Perineuriomas have mostly simple karyotypes, with one or few chromosomal rearrangements or numerical changes and it seems that specific cytogenetic aberrations may correlate with perineurioma subtype.0Comments 57Citations
- [Show abstract] [Hide abstract] ABSTRACT: Hybrid peripheral nerve sheath tumors (PNSTs) are recently recognized, rarely reported entities. Very few hybrid PNSTs with elements of perineurioma have been reported. We report a case of a 47-year-old man who presented with multiple (>20) cutaneous nodules on all 4 extremities, present since childhood. The patient and his family had no history of other PNSTs, other neural-origin tumors, or genetic disorders, including neurofibromatosis. Five excised lesions are well circumscribed but unencapsulated nodular tumors composed of cytologically bland spindled cells with tapering nuclei and indistinct cytoplasm arranged in a storiform pattern in a collagenous matrix. Scattered among these cells are large granular eosinophilic cells. The spindled cells are epithelial membrane antigen-positive and S-100 protein negative. The cytoplasm of the granular cells contains abundant S-100 protein, NK1/C3, and CD68-positive granules. Sparse nerve fascicles contain neurofilament-positive axons. Each tumor also contains poorly marginated areas that histologically resemble pure granular cell tumor, and superficial biopsies of these tumors can histologically resemble pure granular cell tumors. Considering a Schwannian origin for both perineurial and granular cells can provide a logical explanation for the pathogenesis of this case. To the best of our knowledge, our case is the first report of multiple hybrid granular cell tumor-perineurioma.0Comments 19Citations