Case Of Plexiform Schwannoma Research Articles

34. Recurrent vulvar plexiform schwannoma: an unusual variant in an unusual site

A 5-year-old girl presented with a 3 year history of a slow-growing lump in the right labia minora. On examination, a 20×15 mm mass was attached to the overlying vulva skin. After an initial incomplete resection the lump recurred twice, with subsequent repeat excisions 10 and 12 years after initial presentation. Microscopic examination of all three excisional biopsies revealed classical histological features of plexiform schwannoma, namely Antoni A and B areas including Verocay bodies and a multinodu-lar architecture. The most recent excision performed in 2012 also contained scattered bizarre pleomorphic nuclei, consistent with ancient change. Diffuse strong positive staining for S100 was seen. Plexiform (multinodular) schwannoma is an uncommon variant of schwannoma, accounting for approximately 5%. This variant is characterised by a multinodular growth pattern, and can occur in both conventional and cellular types of schwannoma. Plexiform schwannomas can occur in both superficial and deep soft tissues, however the vulva is an uncommon site. Most cases of plexiform schwannoma have no association with neurofibromatosis. Plexiform neurofibroma is an important differential diagnosis to exclude. As seen in our case, plexiform schwan-noma can recur locally, which is thought to be related to the mul-tinodular growth pattern. Malignant transformation and distant metastases of plexiform schwannoma have not been reported.

Plexiform schwannoma of the duodenum accompanying pyloric stenosis: Report of a case

Plexiform schwannoma is a benign peripheral nerve sheath tumor and is composed of Schwann cells arranged in a plexiform pattern. Most plexiform schwannomas are skin tumors, and there has been no case report of this tumor originating in the duodenum. We describe the first known case of plexiform schwannoma of the duodenum. A 60-year-old man presented with a short history of food intolerance, epigastric discomfort, fullness and bloatedness, sometimes vomiting, and weight loss, without any clinical picture of neurofibromatosis. Upper gastrointestinal endoscopy revealed pyloric stenosis with normal mucosal lining. The computed tomography demonstrated circumferentially and concentrically thickened pylorus up to 18 mm with narrowed lumen and limited contrast passage. Antrectomy and gastrojejunostomy were performed due to unknown etiology of the obstruction. The cut surface of the lesion revealed thickened pylorus up to 15 mm in a circumferential manner. It contained a 5 mm tumor consisted of multiple white nodules in the submucosal and subserosal layers with overlying duodenal mucosa. Microscopic examination revealed nodular structures composed of spindle cells within fascicular pattern without any atypia or mitosis. Immunohistochemical examination revealed that the cells diffusely and strongly expressed S100 proteins in a nuclear and cytoplasmic pattern, but not CD117, smooth muscle actin, desmin, or CD34, confirming plexiform schwannoma.

Unusual intramaxillary plexiform schwannoma

Neoplasms of peripheral nerve in the head and neck region are of common occurrence, but origin in the oral and para-oral tissues is uncommon and they rarely occur centrally within the jaws. Schwannoma is a benign neoplasm originating from the neural sheath of peripheral soft tissues, but its occurrence within the jaw bones is most unusual. Plexiform schwannoma is a unique variant of Schwann cell tumours having plexiform pattern. Literature revealed only one case of plexiform schwannoma of the jaw bones, i.e. involving the mandible. In this report, we present the first documented case of intraosseous plexiform schwannoma of the maxilla, an extremely rare benign neurogenic tumour treated surgically. Schwannoma is a benign neoplasm originating from the neural sheath of peripheral soft tissues, but to occur within the jaw bones is exceptional. Plexiform schwannoma is a rare variant of Schwann cell tumour having plexiform pattern of intraneural growth with multinodularity. Plexiform schwannoma is a benign neoplasm with no malignant potential, but recurrences are evident if excised incompletely. Plexiform schwannoma has similar clinical and histopathological features as that of plexiform neurofibroma which has high malignant potential; hence, it is imperative to correctly diagnose and differentiate this lesion as treatment modality of these two lesions differs.

Plexiform schwannoma. Immunohistochemistry of Schwann cell markers, intermediate filaments and extracellular matrix components

An immunohistochemical study using a comprehensive panel of antibodies to Schwann cell markers, intermediate filaments and extracellular matrix components has been performed on three cases of plexiform schwannoma. All tumour cells expressed S 100 protein, Leu 7-HNK 1 antigen and vimentin; glial fibrillary acidic protein was detected in many tumour cells. In addition, expression of cytokeratin was also demonstrated in one case. The associated extracellular matrix was found to be reactive with antibodies to laminin, heparan sulfate proteoglycan, fibronectin, type I, III, IV and VI collagen. It is concluded that Schwann cells producing their own extracellular matrix are the main components of these tumours. The significance of the cytokeratin expression and the possible role of the extracellular matrix in regulating Schwann cells' proliferation in peripheral nerve tumours are discussed.