A black female newborn, weighing 3800 g, was born at 42 weeks' gestation by normal spontaneous vaginal delivery to a 22-year-old mother after an uncomplicated pregnancy. At birth, the baby was noted to have a 3 × 2 × 1.5-cm, nontender, nonpulsatile, midline, pedunculated buccal mass arising from the upper alveolar ridge of the maxilla. The mass protruded from the mouth on crying and then prolapsed in the oral cavity. The patient had mild stridor due to impingement of the airway.
The baby was taken to the operating room 5 hours after delivery for excision of the mass. The preoperative diagnosis was a possible teratoma, indicated by the presence of a pedunculated mass protruding from the gingiva of the anterior maxilla (Figure 1, arrow). The mass was excised under general anesthesia, and the patient had an uneventful recovery. Grossly, the excised lesion was a fleshy, lobulated, tan mass.
Microscopic examination revealed closely packed large cells separated by a thin capillary network with an overlying flattened squamous epithelium (Figure 2; hematoxylin-eosin, original magnification ×100). On closer inspection, the large polygonal cells making up the mass had an eosinophilic, finely granular cytoplasm with small, uniform, eccentrically located nuclei. Occasional odontogenic epithelial rests that were sharply demarcated from the surrounding granular cells were present (Figure 3, arrow; hematoxylin-eosin, original magnification ×400).
What is your diagnosis?
Pathologic Diagnosis: Congenital Gingival Granular Cell Tumor (Congenital Epulis)
Congenital gingival granular cell tumors (CGGCTs) are rare benign tumors of uncertain histogenesis. They occur almost exclusively along the alveolar ridge of the maxilla in white female newborns and are not associated with congenital malformations or deformities of the teeth.
These tumors were first described in 1871 by Neumann and were referred to as “congenital epulis.”1 The Greek word epulis means “swelling on the gingiva.” Over the years, this term has been used to describe a variety of diverse lesions, and because of this history it should not be used for this specific tumor.2
Lack et al1 reported the largest series of CGGCTs to date, for which the authors collected data for more than 30 years (1947–1977) and reviewed 21 cases. In this series, the anterior maxillary alveolus was affected twice as often as the mandible, with no involvement of the underlying bone or unerupted teeth.
Congenital gingival granular cell tumors are usually single lesions, but the incidence of multiple lesions is 10%.1 Even when multiple lesions occur, they tend to occur in the soft tissue of the maxilla or the mandible. Rare cases have been reported to occur in the mandible and the tongue.2 Autopsy performed on a 29-week-old infant was found to have CGGCT affecting multiple organs, hence other sites of involvement should be sought.1 These tumors vary from 0.1 to 4 cm in diameter; the largest CGGCT reported to date measured 7.5 cm1 in diameter. One case of CGGCT was described in a newborn with congenital goiter. Another case had an associated midfacial hypoplasia, but this was attributed to the large maxillary mass, which caused a deformity of the mandible and resulted in inhibition of growth.3 Congenital gingival granular cell tumors occur sporadically, and no familial tendencies have been described. Two patients with these lesions subsequently delivered unaffected babies.1
Congenital gingival granular cell tumors usually present at birth as incidental findings; however, when large or multiple, they may precipitate respiratory or feeding problems.2 One case was detected on prenatal ultrasound during investigation of maternal polyhydramnios.4
The striking predilection of CGGCT for female infants (incidence of 8:1) suggests the presence of an endogenous hormonal stimulus in utero. This theory is further supported by the experimental production of granular cell tumor in the uterine cervix of newborn mice following the injection of estrogen.1 However, estrogen and progesterone receptor studies done on human CGGCTs were negative.3
Histologically, CGGCTs are strikingly similar to the more common adult granular cell tumors. They both are composed of polygonal cells with abundant granular cytoplasm and small eccentric nuclei with occasional small nucleoli. A delicate capillary network separates the cells. In contrast to granular cell tumors, there is no pseudoepitheliomatous hyperplasia of the overlying squamous mucosa in CGGCT, and no nerve bundles are seen within these lesions. Furthermore, CGGCTs were shown to be consistently negative when immunostained with S100 protein, in contrast to adult granular cell tumors, which are derived from Schwann cells. Similarly, our case was negative for S100 protein immunostain.
The histogenesis of CGGCTs is uncertain, despite electron microscopy and immunohistochemical studies. Suggested progenitor cells include undifferentiated mesenchymal cells, fibroblasts, myofibroblasts, histiocytes, Schwann cells, and odontogenic epithelium. An odontogenic origin was suspected because small nests of odontogenic epithelium were found in 37% of cases reported by Lack et al.1 These islands, however, were sharply demarcated from the surrounding granular cells, which on ultrastructural examination showed mesenchymal rather than odontogenic features. It is likely that the odontogenic rests are incidentally trapped in the tumor.
The clinical course of these lesions suggests they are probably not neoplastic, but rather degenerative or reactive lesions responding to an unclear initiating event. This theory is supported by the lack of recurrence of incompletely excised lesions. It was also reported that lesions excised later in the neonatal period show evidence of involution.1 To date, our case has not shown any evidence of recurrence or problems in dentition.
The differential diagnosis of CGGCT can include a variety of rare lesions, such as teratoma, leiomyoma, congenital dermoid cyst, congenital cystic choristoma, congenital fibrosarcoma, and congenital lipoma.5 No standard protocol exists for the management of these lesions; some advocate observation only, except in symptomatic cases. Most often, these tumors are surgically removed to confirm the nature of the lesion.
References
The authors have no relevant financial interest in the products or companies described in this article.
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