Oral granular cell tumor: a collaborative clinicopathological study of 61 cases

Background: Granular Cell Tumor (GCT) is an uncommon benign lesion in the oral cavity whose pathogenesis remains poorly understood. Due to their infrequent occurrence and similarity to other oral lesions, they are often forgotten during the initial clinical diagnosis. Therefore, understanding its prevalence, clinical and pathological characteristics is crucial for an accurate diagnosis and adequate management.

Methods: All cases diagnosed as GCTs in six Brazilian and Argentinian oral diagnostic centers were re-evaluated by HE staining, and clinical, demographic, and histopathological data were collected and evaluated.

Results: The series comprised 45 female (73.8%) and 16 male (26.2%), with a 2.8:1 female-to-male ratio and a mean age of 35.3 ± 16.9 years (range: 7-77 years). Most cases occurred on the tongue (n = 49; 81.6%) and presented clinically as asymptomatic papules or nodules (n = 50; 89.3%) with a normochromic (n = 25; 45.5%) or yellowish (n = 11; 20.0%) coloration and sizes ranging from 0.2 to 3.0 cm (mean ± SD: 1.40 ± 0.75 cm). Morphologically, most tumors were characterized by a poorly delimited proliferation (n = 52; 88.1%) of cells typically rounded to polygonal containing abundant, eosinophilic, finely granular cytoplasm. Pustulo-ovoid bodies of Milian were identified in all lesions (n = 61; 100%). Entrapment of skeletal striated muscle (n = 44; 72.1%) and nerve fibers (n = 42; 68.9%) were common findings. Pseudoepitheliomatous hyperplasia (PEH) was observed in 23 cases (39.0%). In only 27.7% of cases (n = 13) there was agreement between the clinical and histopathological diagnosis. Outcome information was available from 16 patients (26.2%), with clinical follow-up ranging from 4 to 36 months (mean 13.3 months), and none developed local recurrence.

Conclusions: The clinical and histopathological features of GCTs were consistent with those described in previous studies. In general, these lesions have a predilection for the lateral region of the tongue in adult women. It is essential to consider GCTs in the differential diagnosis of yellow or normochromic papules and nodules in the oral cavity. Histopathological evaluation is essential for the definitive diagnosis and the prognosis is excellent.