Congenital Epulis (Congenital granular cell tumor)
Congenital granular cell epulis (CGCE) is a rare, benign tumor seen almost exclusively in neonates. It was first described in 1871 by Neumann (1), and has many synonyms including congenital granular cell lesion, congenital epulis of newborn, gingival granular cell tumor of infancy, congenital granular cell myoblastoma, granular cell fibroblastoma, and Neumann tumor. The word "epulis" means "swelling of the gingiva" in Greek. The WHO Classification of Head and Neck Tumors includes CGCE as a tumor of uncertain histogenesis (2). This is a rare benign tumor that classically occurs on the alveolar processes in the oral cavity of newborns. CGCE occurs much more commonly in female neonates than male neonates (F:M 9-10:1) and can be diagnosed prenatally. Very rarely, they can be multiple or found in other locations within the oral cavity (3, 4). The lesions are often pedunculated and range in size from 1 cm to several cm (2, 5).
Histologically, CGCE is composed of sheets and nests of large polygonal cells with well-delineated cell membranes and eosinophilic granular cytoplasm. The nuclei are usually small and uniform. Pseudoepitheliomatous hyperplasia of the overlying mucosa is not a feature, and the overlying surface epithelium is often attenuated. Numerous small, thin-walled blood vessels are found throughout the lesion (2). CGCE with a spindle cell component has been described (6).
The expected immunohistochemical profile of CGCE is largely negative, including S-100, keratins, EMA, myogenous markers, and hormone-related markers. Neuroendocrine markers such as PGP9.5 may be positive, as may be vimentin. Histiocytic markers are variably positive (7). GLUT-1 has also been found to be negative (8).
The clinical management includes surgical excision, particularly if the mass is impairing feeding or respiration. Conservative treatment can be considered for small, asymptomatic lesions, as some lesions will regress spontaneously. Local recurrence is rare, even with incompletely excised lesions, and malignant transformation has not been reported (2).
Histologically, the differential diagnosis includes granular cell tumor (GCT), however the clinical context will be different. GCT usually occurs in older patients, and is rarely seen in the first decade of life. Both lesions are composed of large polygonal cells with granular eosinophilic cytoplasm. Characteristically, CGCE has an overlying atrophic mucosa while GCT often has overlying pseudoepitheliomatous hyperplasia. Immunohistochemistry for S-100 protein is also helpful: in CGCE it will be negative, while GCT usually shows strong positive staining (7).
The differential diagnoses of gingival masses in a neonate/infant include melanotic neuroectodermal tumor of infancy, hemangiomas and other vascular malformations, oropharyngeal teratoma, congenital fibrous epulis, pyogenic granuloma, and dermoid cyst. Pathologic examination and routine light microscopy is sufficient to resolve the differential diagnosis in many instances of neonatal/infantile gingival masses.
Contributed by Maren Y. Fuller, MD and Miguel Reyes-Mugica, MD