Ⅰ.Introduction
Pigmented lesion that are difficult to classify into the recognized types of melanotic lesions are seen in the oral cavity. Oral hyperpigmentation may be focal or diffuse, acquired or familial, and due to endogenous or exogenous factors. Localized areas of increased melanin in the oral mucosa that are not associated with systemic diseases or syndromes have been variably termed ephelis, lentigo, melanoplakia, melanotic macule, and focal physiologic melanosis.(1)
Oral hyperpigmentation is common in patients older 40 years. But lesions in a newborn are unusual(2) and the congenital melanotic macule of the tongue has rarely been reported.(3) To the best of our knowledge, there are only seven well-documented cases reported.(4-6) The oral melanotic macule presents as a flat, blue, brown, or black, mostly solitary lesion less than 10mm in diameter. (3) with the gingiva and lip the most frequently affected locations. (7) They were present at birth and had grown proportionately since, with sizes ranging from 0.3 to 3 cm. The congenital melanotic macule are evident at birth or shortly thereafter. Although they affect approximately 1% to 2% of newborns, they are much less common than acquired melanocytic nevi.(8-9)
When they are present, the clinical diagnosis is not always apparent.(2) This report a lesion that fulfils the criteria of melanotic macules on the tongue of a newborn.
Ⅱ.CASE REPORT
The oral and maxillofacial surgery department at the St.mary’s hospital of catholic university of korea was consulted to evaluate a 2-month-old infant with 3 pigmented lesion on on the right side of the dorsal tongue. The lesions were brown black but not homogeneous in color, smooth, nonblanchable, and nonpalpable, with irregular margins. (Fig 1) The sizes of the 3 lesions were approximately 8 X 5 mm, 6 X 5 mm, 1 X 1 mm. No other pigmented lesions were present on the buccal mucosa or on the skin of body. No bleeding or ulceration was seen. The history indicated proportional growth of the lesion since birth.
The infant was in good health and fed normally. He had not received any medication. His mother had been healthy during pregnancy. The patient’s medical history was noncontributory to the lesion. The family history was negative for melanoma, polyposis, and mucosal pigmentation. The results of the rest of the physical examination were normal. There was no regional lymphadenopathy. Examination of the entire cutaneous surface of the body revealed no similar enlarged pigmented lesions.
The differential diagnosis included posttraumatic lesion, hemangioma, nevi, melanotic macule, malignant melanoma, and pigmented lesions associated with endocrine disorders or different syndromes (Peutz-Jeghers, neurofibromatosis, Addison disease). On laboratory finding of neonatal screening test by tandem mass spectrometry, there was no endocrine disorder.
The multiple melanotic lesions on the tongue present at birth with subsequent proportional growth ranged from 0.1 to 10mm, but there was negative family history of systemic conditions associated with hyperpigmentation. From these features, clinical diagnosis of the lesion was congenital lingual melanotic macule.
We recommend excisional biopsy under general anesthesia because of possibility of malignancy, but parents refuse invasive procedure. On a following-up examination of the child at the age of 1 year, the pigmented lesions were unchanged.
Ⅲ.DISCUSSION
In the past, terminology for oral melanotic macules of the oral mucosa and skin has confused. Various terms are used for oral melanotic macules of the mucosa and skin, such as ephelides, melanosis, lentigo, melanotic macule, and oral melanocytosis. Current terms for lesions with oral and lingual melanotic macules have been standardized by Weather et al in 1976 and Page et al in 1977.(3)
The cause of congenital lingual melanotic macule is unclear. The congenital macule may represent a hematoma of melanocytes with localized functional change in melanin production. Also, there are reports of acquired oral melanotic macules after trauma, irradiation, or medication. Various hypotheses for localized increased melanin production have included physiologic genetic variations or viral and immunologic factors, but none has been conclusive.
Clinical diagnosis of congenital lingual melanotic macule should be considered when the following criteria apply: solitary or multiple melanotic lesions on the tongue; presence at birth with subsequent proportional growth; and a negative family history for systemic conditions associated with mucosal pigmentation.(3)
Oral hyperpigmentation is not uncommon in individuals older than 40 years, but Congenital lingual melanotic macules are a rare entity, of which there are only seven well-documented cases reported in the Literature.(2-3)
Oral hyperpigmentation may represent many conditions and diagnoses.(10-12) These range from physiologic melanin pigmentation to systemic disease as well as drug (antimalarials, antibiotics, and chemotherapeutic agents) or toxin (heavy metals and smoker’s melanosis) related pigmentation. Other causes include pigmented fungiform papillae,(13) Peutz-Jeghers syndrome, Addison disease, von Recklinghausen neurofibromatosis, Laugier-Hunziker syndrome (14-15), pigmented nevi, and malignant melanoma(16)
Most of these diagnoses can be excluded by medical history and physical examination. Because of the child’s young age, smoker’s melanosis and amalgam tattoo, heavy metals, Kaposi’s sarcoma are excluded. Posttraumatic melanotic macule is excluded because there was no history of trauma. Postinflammatory pigment alteration usually fades with time and often includes a history of other dermatoses. On the neonatal screening test by tandem mass spectrometry, there was no related endocrine disorder or syndrome. Addison disease was excluded because of absence of systemic involvement. The pigmentation in Peutz-Jeghers syndrome was excluded because there was no gastrointestinal polyposis and family history. Laugier-Hunziker syndrome was also excluded because it is often associated with melanonychia. In pigmented fungiform papillae, the pigmentation is confined to these papillae. Pigmented lesions such as mucosal melanocytic nevi or melanomas are more difficult to distinguish. Although oral melanotic macules are considered benign, careful follow-up is recommended because the benign oral melanosis can transform into melanoma. (20) Assessing their potential for malignant change is important and biopsy is often necessary. (17-18)
The congenital lingual melanotic macule in this case appeared at birth on the dorsal surface of the tongue, and they had proportionally grown but stopped. Congenital melanotic macule shares the benign features of other oral melanotic macules, but a biopsy is recommended. In this case, patient was too young to endure the invasive procedure, biopsy was not done. On a following-up examination of the child at the age of 1 year, the pigmented lesions were unchanged. 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.
