Case report

Multiple granular cell tumors of the oral cavity: Report of a case and review of the literature

El tumor de células granulares (TCG) es una lesión poco frecuente que aparece predominantemente en mujeres y en el área de cabeza y cuello. Múltiples estudios apuntan a que deriva de las células de Schwann y su perfil inmunohistoquímico ha sido ampliamente estudiado. La expresión de calretinina (CRT) es, sin embargo, la peor caracterizada en el TCG, por ello en este estudio se pretende analizar en detalle su expresión en esta forma tumoral.

Se analizó una amplia muestra de TCG (n = 43), de los que se recogieron datos clínico-epidemiológicos y se realizó inmunotinción en todos ellos con anticuerpo anti CRT estudiando su patrón de expresión.

Se encontró que este tumor muestra positividad global frente a CRT en una amplia mayoría de los casos (74%), encontrando un gradiente en la inmunotinción en el 53% de los TCG estudiados, situación observada en los tumores con superficies epiteliales en proximidad y que no ocurre cuando estos epitelios se encuentran ausentes o alejados del TCG.

La tinción frente a CRT es útil para el diagnóstico del TCG y se demuestra la existencia de un gradiente en la inmunotinción cuando el TCG se encuentra en la proximidad de epitelios escamosos, sobre todo cuando estos muestran hiperplasia epitelial pseudoepiteliomatosa, lesión a la que frecuentemente se encuentran asociados.

Granular cell tumour (GCT) is a rare lesion which predominately affects women and occurs most frequently in the head and neck. Many reports suggest that the tumour cells are probably derived from Schwann cells. The immunohistochemical profile of GCT has been extensively studied, although calretinin expression (CRT) is the least understood. Our aim is to undertake a detailed analysis of its expression in this tumour.

A large sample of GCT (n = 43) was analysed. Clinical-epidemiological data were collected and immunostaining with CRT was performed in all of them with anti-CRT antibody to study its expression pattern.

We found that most of the GCT cases were positive to CRT (74%). Furthermore, in 53% of cases, we detected an intensity gradient in the immunostaining in tumour cells with epithelial surfaces in proximity, which does not occur when these epithelia are absent or distant from the GCT.

CRT is a useful marker for the diagnosis of GCT. We found the existence of an immunostaining intensity gradient when the tumour is in close proximity to squamous epithelia, especially when these show pseudoepitheliomatous epithelial hyperplasia, which is often associated with GCT.

Granular cell tumour, also known as Abrikossoff tumour, is a relatively uncommon benign neoplasm, which is more commonly found in females in the 4th to 6th decades of life even though it can occur in all ages.

It occurs in all areas of the body but about 45–65% of all lesions are reported in the head and neck region. Intraoral lesions represent about 70% of the granular cell tumours of the head and neck, and account for 1/3 of all cases affecting the whole body.

Most of the intraoral lesions occur on the tongue, usually on the lateral aspect, followed by the buccal mucosa and hard palate. Although majority of granular cell tumours are benign, some are clinically aggressive and a few frankly malignant forms have been reported. Some benign lesions exhibit surface ulcerations and this clinical appearance, combined with the overlying pseudoepitheliomatous hyperplasia, seen histologically, may lead to misdiagnosis of malignancy if adequate biopsy material was not taken.

A case of granular cell tumour which occurred on the midline area of the dorsum of the posterior 1/3 of the tongue is reported in a 20-year-old female patient. It is interesting because the patient was younger than the average age of occurrence and the tumour occurred in a similar site to that of a lingual thyroid.