Oral Granular Cell Tumour: A Case Report ^†

1. Case Presentation

A 16-year-old girl presented at our attention with an asymptomatic nodular lesion on the tongue. Clinically, the lesion appeared as a submucosal smooth nodule, 5 mm in diameter, covered by a pink-yellowish looking mucosa (Figure 1). On palpation, it was well defined, but not encapsulated. The lesion was located on the right posterior dorsum of the tongue, it had been slowly growing for a few months, and it was completely asymptomatic. The patient’s anamnesis revealed atopic dermatitis and pityriasis rosea.

Clinically, the lesion was placed in differential diagnosis with other “soft tissue tumors”. Therefore, an excisional biopsy of the lesion was performed with subsequent histopathological analysis.

2. Histopathology

The connective tissue displayed a well-defined proliferation of cells with a characteristic granular cytoplasm. The cells had a characteristic granular eosinophilic cytoplasm positive to PAS staining. The neoplastic cells had a polygonal shape, large dimensions and indefinite margins (Figure 2). The nucleus was roundish and with free chromatin. There was no nuclear atypia and the Ki-67 proliferation index was low. A peculiar histological element of the granular cell tumor was the presence of pseudoepitheliomatous hyperplasia (PEH).

3. Conclusions

Granular cell tumor (GCT) is a benign soft tissue neoplasm. GCT can develop throughout the body but it shows a clear preference for the head-neck district. In particular, in 50% of cases it develops on the tongue, precisely on the lateral margins and back of the tongue [2].

PEH places this lesion in a differential diagnosis with a well-differentiated squamous cell tumor [3]. In order to avoid dangerous diagnostic errors, which can lead to unnecessary lingual mutilation, it is essential to perform a correct biopsy test. Bioptic sampling must include both the epithelial lamina and the lamina propria, where the granular cell tumor develops.