Multiple Hybrid Granular Cell Tumor-Perineuriomas

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.

Peripheral nerve sheath tumors of the gastrointestinal tract: a multicenter study of 58 patients including NF1-associated gastric schwannoma and unusual morphologic variants

“…A neurogenic derivation of GCTs has been demonstrated in several studies, and a schwannian line of differentiation is currently widely accepted [11]. GCTs have been documented in the setting of NF1 [12] and as a novel component in hybrid PNSTs of soft tissue [13]. However, their distinct histology warrants their separation from neurofibroma and schwannoma.…”

A Benign Cutaneous Plexiform Hybrid Tumor of Perineurioma and Cellular Neurothekeoma

“…These combinations include a mixture of neurofibroma and schwannoma, [6][7][8][9][10][11][12] schwannoma and perineurioma, [13][14][15][16][17][18] neurofibroma and perineurioma, 14,[19][20][21] and perineurioma and granular cell tumor. 22 Only 1 described case included a triphasic combination of neurofibroma, schwannoma, and perineurioma. 23 We present the clinicopathologic and immunohistochemical characteristics of 9 cases of a benign cutaneous plexiform nerve sheath tumor located on the lips, with hybrid features of perineurioma and cellular neurothekeoma.…”

Vascular invasion and other invasive features in granular cell tumours of the skin: a multicentre study of 119 cases

“…The authors interpreted the presence of perineural cells as a hyperplastic or reactive phenomenon, different from the perineural neoplastic component of the hybrid nerve sheath tumours or perineurioma 6. On this topic, only one case of multiple hybrid granular cell tumour perineuromas has been described, in which the perineural component was clearly neoplastic 11. The propensity of granular cell tumours to develop and expand along nerve fascicles, and therefore to display frequent perineural spread with perineural hyperplasia, is most probably related to the differentiation towards nerve sheath.…”