Value of ultrasound in the diagnosis of intraneural perineurioma / 中华超声影像学杂志

Objective:To investigate the value of ultrasound in the diagnosis of intraneural perineurioma.Methods:From June 2015 to June 2022, 11 patients with intraneural perineurioma confirmed by surgery or biopsy in Provincial Hospital Affiliated to Shandong First Medical University were retrospectively collected, all of whom underwent high-frequency ultrasound examination. Clinical data and sonographic characteristics were collected. The maximum cross-sectional area of the affected nerve was recorded and compared with the corresponding site of the contralateral nerve.Results:All the 11 cases of intraneural perineurioma were single neuropathy. The sonogram showed that the affected nerve was spindle shaped and thickened. There was a statistical difference between the maximum cross-sectional area of the thickened intraneural perineurioma and the corresponding site of the contralateral nerve [(0.158±0.043)cm vs (0.044±0.012)cm, t=8.669, P<0.001]. The fascicles of the affected nerve were thickened with loss of normal fascicular definition, but there were still hyperechoic linear separation among the fascicles. Conclusions:High-frequency ultrasound may be a valuable technique for the diagnosis of intraneural perineurioma.

Hybrid schwannoma/perineurioma: a clinicopathological analysis of 35 cases / 中华病理学杂志

Objective@#To investigate the clinical pathological features, pathological diagnosis and differential diagnosis of hybrid schwannoma/perineurioma.@*Methods@#The clinicopathological data of 35 cases were collected at Fudan University Shanghai Cancer Center, from October 2010 to August 2017; morphological observation and immunohistochemical staining were performed, and the literatures were also reviewed.@*Results@#There were 7 males and 28 females (male∶female=1∶4), patients with onset age ranging from 3 to 81 years(mean=36 years). Of 35 tumors, 11 cases occurred in the head and neck, 10 in the extremities, 9 in the trunk, 4 in the intestine, and 1 in the labiamajora, respectively. Clinically, most patients presented as a slowly growing dermal nodule, sometimes associated with pain. The duration of symptoms ranged from 1 month to 20 years before excision. Tumor size ranged from 0.8 cm to 6.0 cm (mean=2.6 cm). Microscopically, the tumors were usually well circumscribed but unencapsulated. At low power, most tumors were located in the dermis or subcutis, and several cases in the submucosal tissues. The tumors were composed of fascicular, storiform or whorled growth of closely intermixed plump spindle cells and slender spindle cells. The plump spindle cells had ill-defined eosinophilic cytoplasm with larger tapered or wavy nuclei, whereas the slender spindle cells had comparatively delicate nuclei with elongated cytoplasmic processes. Tumor cells had no obvious atypia, and mitoses were rare. Scattered large cells with degenerative nuclear atypia were seen in some cases. By immunohistochemistry, most of plump spindle cells showed strong staining of S-100 protein(35/35) and SOX10(8/9), whereas slender spindle cells stained variably for epithelial membrane antigen(31/35), CD34(32/33), Claudin-1 (15/15) and GLUT-1(8/8). Ki-67 proliferation index were all less than 5%. Follow-up data available in 16 patients (range 4 to 72 months; mean=46 months) were all free of disease, and one case developed local recurrence.@*Conclusions@#Hybrid schwannoma/perineuriomaisa benign nerve sheath tumor that typically manifests as a dermaland subcutaneous tumor, less frequently may affect uncommon sites such as the nasal cavity, the gastro-intestinal tract, and the external genital areas. The tumors consisted of intimately admixed plump-spindled schwannian cells and slender-spindled perineurial cells showing dual differentiation of strong S-100 protein and SOX10 expression in the former component and variable immunoreactivity of epithelial membrane antigen, Claudin-1 and CD34 in the latter. It should be aware of the possibility of potentially misinterpretation of hybrid schwannoma/perineurioma as dermatofibrosarcoma protuberans and solitary fibrous tumor and so on.

Malignant peripheral nerve sheath tumour with perineurial differentiation and hyaline eosinophilic globules (thanatosomes): A rare tumour

@#Malignant peripheral nerve sheath tumour (MPNST) with perineurial differentiation is a rare variant of MPNST. The pathological features and clinical significance of this variant remain to be characterised. We reported the clinicoradiological and pathological features of a case of recurrent right arm mass related to the ulnar nerve in a 42-year-old female patient. On pathological examination, the tumour showed dual features of conventional and perineurial MPNST which was proven by positive immunostaining for S-100 and EMA. The pathological diagnosis was MPNST with perineurial differentiation. In addition, a peculiar and rare finding of intracytoplasmic eosinophilic hyaline globules (thanatosomes) within tumour cells is reported. We document a rare tumour with hybrid features between conventional and perineurial MPNSTs. Further studies are needed to establish its biological behaviour.

Multiple Intradermal Soft Tissue Perineuriomas of the Digit / 대한피부과학회지

Perineurioma is a rare benign peripheral nerve sheath tumor, composed uniformly of perineurial cells. Soft tissue perineurioma primarily arises within the subcutaneous tissue of extremities and trunk as a painless solitary nodule, and should be distinguished from dermatofibroma, neurofibroma, dermatofibrosarcoma protuberans, meningioma and so on. A 25 year-old female is presented with three small asymptomatic papules on the third left finger which were found 3 years ago. Punch biopsy was performed on all of the papules. Microscopic examination demonstrated well-demarcated tumor within dermis, and proliferation of spindle cells with wavy nuclei and elongated bipolar cytoplasmic process, arranged in a whorled pattern. According to immunohistochemical analysis, the tumor cell showed positivity for epithelial membrane antigen, but negativity for S-100 protein, factor XIIIa, CD34, and smooth muscle actin. The diagnosis of soft tissue perineurioma was being made. We report this rare case of perineurioma presented as multiple papules localized within dermis of the digit.

A Soft Tissue Perineurioma and a Hybrid Tumor of Perineurioma and Schwannoma

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.

Malignant transformation in a hybrid schwannoma/perineurioma: Addition to the spectrum of a malignant peripheral nerve sheath tumor.

Benign nerve sheath tumors include schwannomas, neurofibromas and perineuriomas. The malignant counterpart of a nerve sheath tumor is designated as a malignant peripheral nerve sheath tumor (MPNST). Lately, benign nerve sheath tumors comprising more than one component have been described, including hybrid schwannomas/perineuriomas. However, malignant transformation in a hybrid schwannoma/perineurioma has not been documented so far. Herein, we present a rare case of a young adult male who presented with a soft tissue mass in his right thigh that was excised elsewhere and submitted to us for histopathological review. One of the tissue sections displayed histopathological features of a hybrid schwannoma/perineurioma, including alternate arrangement of benign schwann and perineurial cells, reinforced with S100-P and epithelial membrane antigen positivity, respectively, along with low MIB1 and negative p53 immunostaining. The other two tissue sections showed a spindly sarcomatous tumor that was immunohistochemically positive for S100-P, CD34, p53 and exhibited high MIB1 (30-40%). Diagnosis of a MPNST arising in a hybrid schwannoma/perineurioma was made. This unusual case forms yet another addition to the spectrum of a MPNST.

Perineuroma de tejidos blandos en pared abdominal: hallazgos anatomopatológicos y revisión de la literatura / Abdominal wall soft tissue perineurioma: autopsy findings and review of the literature

El perineuroma es un tumor benigno raro que deriva de las células perineurales de la vaina del nervio. Fue descrito por primera vez en 1978 por Lazarus y Trombetta, quienes basaron su diagnóstico en las características ultraestructurales de las células de esta neoplasia. Posteriormente el perfil inmunohistoquímico de las células perineurales permitió la identificación de esta entidad con mayor facilidad. Se describe una mujer de 47 años de edad con tumor en pared abdominal, referida al Hospital de Oncología por diagnóstico de histiocitoma fibroso maligno plexiforme. Se revisó el caso y solicitó inmunohistoquímica. La conclusión fue diagnóstico de perineuroma de tejidos blandos.

The perineuroma is a rare benign tumor, derived from nerve sheath perineurial cells. It was first described in 1978 by Lazarus and Trombetta, who based their diagnosis on the ultrastructural features of perineurioma cells. Subsequently, the immunohistochemical profile of perineurial cells allowed an easier diagnosis of this condition. A case of perineurioma in a 47-year-old woman is reported. The patient presented with an abdominal wall mass, with aprevious diagnosis of malignant fibrous histiocytoma (MFH). The case was reviewed at an oncology hospital, inmunohistochemistry was performed and the concluding diagnosis was soft tissue perineurioma.

Soft Tissue Perineurioma : A Case Report

Soft tissue perineurioma is a very rare tumor composed of entirely of neoplastic perineurial cells. A 54-year-old woman presented with a palpable mass in the right lower leg. The mass was excised. Grossly, the tumor measured 2.0x2.0x1.5 cm. The cut surface was well circumscribed, pale pinkish gray, and rubbery soft. Histological examination showed that the tumor was composed of spindle cells within collagenous and myxoid stroma. The tumor cells had elongated, tapering nuclei with long and thin cytoplasmic processes, and were arranged in fascicular, whorled, and storiform pattern. The tumor cells were positive for epithelial membrane antigen and collagen type IV and negative for S-100 protein. Ultrastructurally, tumor cells showed long and thin cytoplasmic processes, pinocytic vesicles, and incomplete external lamina. The diagnosis of soft tissue perineurioma was confirmed by immunohistochemical stain and ultrastructural study.

A Case of Perineurioma / 대한피부과학회지

Perineurial cells, which normally surround the nerve fascicles within a nerve, can be distinguished from Schwann cells by their immunoreactivity for epithelial membrane antigen and lack of reactivity for S-100 protein. Perineuriomas are uncommon, slowly growing, usually benign tumors composed of well-differentiated perineural cells. We experienced a case of perineurioma in a 44-year-old man. This tumor was a 2 cm sized subcutaneous non-tender movable mass on the left posterior popliteal area. Histologically, the tumor was a circumscribed but non-encapsulated lesion and composed of spindle cells with elongated bipolar cytoplasmic processes, fusiform nuclei, and well-defined palely eosinophilic cytoplasm. Immunohistochemically, most of the tumour cells stained positive with epithelial membrane antigen and vimentin, but failed to stain with S-100 protein, neurofilament, CD34, cytokeratin, chromogranin A, synaptophysin, and Bodian stain.

Soft Tissue Perineurioma

Perineurial cells, which normally surround the nerve fascicles within a nerve, can be distinguished from Schwann cells by their immunoreactivity for epithelial membrane antigen (EMA) and lack of reactivity for S-100 protein. Perineurioma is a form of benign peripheral nerve sheath tumor (PNST) almost exclusively composed of perineurial cells. It is often difficult to differentiate this tumor from the other benign PNSTs or ectopic meningioma by histology alone. Immunohistochemical and electron microscopic studies are helpful for differential diagnosis. We recently experienced a case of soft tissue perineurioma in a 14-year-old girl. This tumor was presented as a 5.6 cm sized subcutaneous movable mass in the elbow. The well encapsulated soft tissue tumor consisted of spindle cells which have whorling and storiform patterns within the collagenous stroma. The spindle cells were stained positive for EMA but negative for S-100 protein, chromogranin, neuron-specific enolase or Leu-7. Ultrastructurally, they possessed long cytoplasmic processes with incomplete basal lamina, primitive intercellular junction and occasional pinocytotic vesicles.