Malignant granular cell tumors: the role of electron microscopy in the definitive diagnosis of an extremely aggressive soft tissue neoplasm

Abstract

Granular cell tumors (GCTs) are rare soft tissue neoplasms which may be multicentric. The vast majority are benign, however approximately 100 malignant GCTs have been reported, with only 8 originating in the vulva. Malignant GCTs are very aggressive with very poor survival rates. As the diagnosis of malignant GCT carries an extremely poor prognosis, the utilization of EM ensures that the most accurate diagnosis possible can be rendered.

Vulvar granular hücreli tümör: Nadir bir olgu sunumu

“…More than 98% of cases have been reported as benign. Malignant GCT, located in the vulva, is extremely rare, and less than ten patients were reported in the literature (10). In the presence of malignancy, the lesions tend to be multicentric and metastatic.…”

“…They can be seen at all ages, with a peak incidence of 50 years (9). The majority of GCTs tend to be benign; however, local recurrences may develop (10). Less than 2% of these tumours were reported as malignant (11).…”

A Case of Synchronous Malignant and Benign Granular Cell Tumor of the Vulva

“…In vulvar GCT, benign multifocal lesions are associated with local recurrence but overall good prognosis (7). Little is known about the clinical prognosis of malignant vulvar GCT, but case reports suggest the potential for aggressive behavior of this entity with associated lymphatic spread to the regional lymph nodes and hematogenous spread to liver and lung (4,6,11,12). Malignant GCT in general is associated with a poor clinical course (1,2).…”

“…As this is a rare tumor, the efficacy of chemotherapy and radiation is limited to case reports and case series which suggest limited efficacy of these modalities (2,6,10). Treatment response to tyrosine kinase pathway inhibitors, such as Pazopanib, has also been reported (1,4). In a multiinstitutional retrospective study of malignant GCTs, all 8 patients died despite radiation and chemotherapy, including tyrosine kinase inhibitors, but these modalities may have prolonged survival and delayed progression (10).…”

“…Vulvar GCTs are typically benign and may be asymptomatic in 30% of cases (3). Although extremely rare, histologically malignant vulvar GCTs have been reported (4). Malignant GCTs are associated with aggressive behavior and metastasis (5).…”