Black Lesion on the Tongue

Abstract

A term female newborn presents with a solitary, well-circumscribed black lesion on the dorsum of the tongue that measures 0.5 × 0.5 cm (Figure 1).Solitary, well-circumscribed black lesion on the dorsum of the tongue Congenital lingual melanotic macule is a clinically distinct entity. It has been observed as a solitary or multiple well-circumscribed, brown lesion(s) on the dorsal surface of the tongue at birth that grows proportionately to the tongue.The cause of congenital lingual melanotic macule is unclear. It is possible that the congenital lesions may represent a hematoma of melanocytes with localized functional change in melanin production. There are sporadic reports of acquired oral melanotic macules appearing after trauma, irradiation, or medication. Various hypotheses for localized increased melanin production in these cases have included physiologic genetic variations or viral and immunologic factors, but none has been conclusive.Oral hyperpigmentation is a common event in older individuals but is exceptional in neonates. When they are present, the clinical diagnosis is not always immediately apparent. Congenital lingual melanotic macules are a rare entity, of which there are only 7 well-documented cases reported in the literature. All cases were present at birth and had grown proportionately since, with sizes ranging from 0.3 to 3 cm.Various terms are used for oral melanotic macules of the mucosa and skin, such as ephelides, melanosis, lentigo, labial lentigo, melanotic macule, and oral melanocytosis. Current terms for lesions with characteristic features of oral and lingual melanotic macules have been standardized by Weather et al in 1976 and Page et al in 1977.Clinical diagnosis of congenital lingual melanotic macule should be considered when the following criteria apply: solitary or multiple melanotic lesions on the tongue, lesion present at birth with subsequent proportional growth, and a negative family history of systemic conditions associated with mucosal pigmentation. The size ranges from 0.3 to 3 cm.The consistent histologic features include increased basal pigmentation with varying degrees of overlying hyperkeratosis. Melanocytic hyperplasia and mild pigment incontinence are minimal. Mitoses or cytologic atypia were not found.Primary malignant melanoma of the oral cavity accounts for approximately 0.2% to 8% of all melanomas and shows a distinct predilection for the maxillary alveolar ridge and palate, whereas the tongue represents a rather unusual site. It is most commonly seen in the 40- to 70-year age group, and there is just one histologically documented transformation or benign oral melanosis into malignant melanoma in an adult patient.Congenital melanotic macule shares the benign histologic features of other oral melanotic macules, and a biopsy is recommended to ascertain this. Although oral melanotic macules are considered benign, careful follow-up is recommended because of the histologically documented transformation of benign oral melanosis into malignant melanoma in an adult.JoDee M. Anderson, MD, MEd, Assistant Editor, Visual Diagnosis, Video Corner; Associate Professor, Director: Pediatric Simulation Education; Medical Director: S.T.A.B.L.E. Simulation Program; Medical Director: Neonatal Resuscitation; Director: Neonatal-Perinatal Medicine Fellowship Program; Associate Director: Media Lab at Doernbecher Children’s Hospital, Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Oregon Health & Science University, Portland, OR.