Soft Tissue Pathology 

Pathology of Perineurioma

Dr Sampurna Roy MD           

Dermatopathology Quiz Case 197

Diagnosis: Soft Tissue Perineurioma





Peripheral nerves are surrounded by an external sheath, which contains concentric layers of thin perineurial cells.

Perineuriomas are rare nerve sheath tumours composed of well-differentiated perineurial cells exhibiting immunoreactivity for epithelial membrane antigen (EMA).

These lesions occur preferentially in adults and may arise in a wide variety of anatomic sites.

There are three main forms of perineurioma:

1. Extraneural Soft tissue Perineurioma: (Including a conventional form)

This is the common type and presents as a painless subcutaneous mass on the limbs or trunk of middle aged adults.

2. Intraneural Perineurioma:

Rare type of lesion. Presents as a swelling of a major nerve in young adults.

3. Sclerosing Perineurioma:

Solitary, small nodule in the finger or palm usually in young adults and is associated with deletion of NF2 gene on chromosome 22.

Other variants:  Fibrous and Reticular Perineuriomas

Microscopic features:


Well circumscribed non-encapsulated lesion composed of spindle cells with eosinophilic cytoplasm and elongated nuclei.The cells are parallel to each other or form small concentric whorls (onion bulbs).

EMA Positive

All perineuriomas are EMA positive (focally in some cases), Claudin-1 positive and S100 protein negative.

Common electron microscopic features are organelle-poor cell processes, many pinocytotic vesicles, sparse intermediate filaments, tight junctions and patchy external lamina.

Sclerosing perineurioma:  Well-circumscribed lesion characterized by small epithelioid cells exhibiting corded, trabecular and whorled growth patters together with spindle cells with wavy nuclei end elongated cytoplasmic processes and thick collagen.

There is focal whorling of tumour cells.

The cells are set in a dense collagenous backround.

Immunohistochemically, most of the tumour cells are positive for epithelial membrane antigen, vimentin, collagen type IV and CD10, but not for S-100 protein, CD34, desmin and cytokeratin.

The tumor cells are positive for the human erythrocyte glucose transporter (GLUT1) antigen suggesting that this could be an useful marker for the identification of sclerosing perineurioma.

Reticular perineurioma:  Microscopically the lesions are characterized by a predominantly lace-like or reticular growth pattern composed of anastomosing cords of fusiform cells with bipolar cytoplasmic processes and palely eosinophilic cytoplasm.

Nuclei were centrally placed, ovoid to fusiform in shape, and no mitoses were seen. Transition to more cellular areas was focally present in all cases.

Differential diagnosis: Myoepithelial tumors, extraskeletal myxoid chondrosarcoma, and myxoid synovial sarcoma.

Cutaneous fibrous perineurioma:  These tumours presented with sharp circumscription of their deep aspect or were not circumscribed on any side.

The cells included plump and spindled with one or more nuclei to  thin, elongated, spindled cells with slender nuclei.

The backround stroma is fibrotic.

Immunohistochemical staining showed EMA-positive  staining of the cellular component  with collagen type IV-positive staining surrounding the cells.

The tumour cells were negative for S-100 protein, factor XIIIa, CD34 and cytokeratin.

Perineuriomas may arise in the intestine usually as intramucosal lesions detected as colorectal polyps with distinctive histologic features including entrapment of colonic crypts.

Intestinal perineuriomas are distinguished from other spindle cell neoplasms of the gastrointestinal tract by immunostaining for EMA and claudin-1.

Soft tissue perineuriomas
:  Behave in a benign fashion and rarely recur.

Atypical histologic features (including scattered pleomorphic cells and infiltrative margins) seem to have no clinical significance.

Note:  Malignant peripheral nerve sheath tumours may show perineurial cell differentiation.

These tumours are epithelial membrane antigen positive and S-100 protein negative.

The prognosis of perineural MPNST appears to be more favorable than that of conventional MPNST.


Further reading:

Images related to Pathology of Perineurioma

Soft tissue perineurioma: clinicopathologic analysis of 81 cases including those with atypical histologic features.

Intestinal perineuriomas: clinicopathologic definition of a new anatomic subset in a series of 10 cases.

Perineurioma: a clinicopathological study of eight cases.

Soft tissue perineurioma: evidence for an abnormality of chromosome 22, criteria for diagnosis, and review of the literature.

Cutaneous sclerosing perineurioma of the digits: an uncommon soft-tissue neoplasm.  Report of two cases with immunohistochemical analysis.

Sclerosing perineurioma: a clinicopathological study of five cases and diagnostic utility of immunohistochemical staining for GLUT1.

Malignant peripheral nerve sheath tumor with perineurial differentiation: 'malignant perineurioma'

Perineurial malignant peripheral nerve sheath tumor (MPNST): a clinicopathologic, immunohistochemical, and ultrastructural study of seven cases.

Soft tissue perineurioma of the finger: expanding the differential diagnosis of a soft tissue tumor presenting on a digit.





Dr Sampurna Roy  MD

Consultant  Histopathologist (Kolkata - India)






Infectious Disease Online


Pathology Quiz Online 


Paediatric Pathology Online


Pancreatic Pathology Online




Endocrine Pathology Online


Eye Pathology Online


Ear Pathology Online


Cardiac Path Online


Pulmonary Pathology Online


Lung Tumour Online




Nutritional Pathology Online


Environmental Pathology Online


Soft Tissue Tumour Online


GI Path Online-India


Gallbladder Pathology Online


E-book - History of Medicine  


Microscope - Seeing the Unseen





Privacy Policy  

Advertising Policy

Copyright 2019