Congenital epulis of the newborn: 10 new cases of a rare oral tumor.

Congenital epulis of the newborn (CEN) is a rare benign lesion that exclusively occurs in the oral and maxillofacial regions of newborns. The clinicopathologic features of CEN were examined and reviewed from the files of the Armed Forces Institute of Pathology from 1970 to 2000. Ten cases were included. Patient lesions were all present at birth but were surgically excised between 2 days and 6 weeks (median, 5.5 days). Nine lesions were in females; 1 case did not designate patient sex. Locations included 6 on the maxilla, 2 on the mandible, 1 on the designated maxillary lip, and 1 unknown. The cases included a patient with 2 lesions: 1 on mandibular and 1 on maxillary alveolar ridges, respectively. All other lesions were solitary and polypoid. Microscopically, these were pedunculated and nodular, composed of sheets to grouped clusters of medium-sized, ovoid-to-polygonal cells with abundant granular cytoplasm, distinct cell membranes, vascular-rich stroma, and attenuated overlying mucosa. Two cases also demonstrated spindled cells. The nuclei were vesicular and focally stippled, with distinct and slightly convoluted nuclear membranes; nucleoli were visible but not prominent. Mitotic activity was not observed. The vascular channels ranged from capillary-sized to venous, some staghorn-like with rare perivascular long-term inflammation. The venules exhibited a perivascular pericytic proliferation. Odontogenic epithelial rests were present in 2 cases. No cases demonstrated cytoplasmic hyaline globules. The lesional cells in all cases were negative for S-100 protein, CD68, CD34, CD31, keratins, desmin, calponin, and smooth muscle actin. Perivenular pericytes were positive for smooth muscle actin. Congenital epulis of the newborn is a rare oral entity with characteristic clinicopathologic features. It predominately affects girls, mainly on the maxillary alveolar ridge. It may be separated from "granular cell tumor" by location, patient age, absence of cytoplasmic hyaline globules, solid growth pattern, pericytic proliferation, attenuated overlying epithelium, and negativity for S-100 protein.