Multifocal oral melanoacanthoma associated with Addison’s disease and hyperthyroidism: a case report

Abstract

Oral melanoacanthoma is a mucocutaneous, pigmented, rare, benign, and probably reactive lesion. This paper reports for the first time in the literature a case of multifocal oral melanoacanthoma in a patient diagnosed with Addison's disease and concomitant Graves' disease with hyperthyroidism. The patient presented with oral pigmented lesions, which were hypothesized to be mucosal pigmentation associated with Addison's disease. Due to their unusual clinical pattern, these oral lesions were biopsied and diagnosed as oral melanoacanthoma on histopathology and immunohistochemistry for HMB-45. At the moment of this report, the patient was being treated for her systemic conditions, but the lesions had not regressed. Reactive hyperpigmentation of the skin and mucous membranes may be found in Addison's disease and hyperthyroidism. This case reinforces the hypothesis of a reactive nature for oral melanoacanthoma and highlights the need for investigation of endocrine disorders in patients with multifocal oral melanoacanthoma.

An extensive intraoral blue nevus in an elder patient

“…Other common symptoms include fatigue, loss of appetite and weight, weakness and hypotension. 5,8 In the present case, the patient had none of these symptoms. If Addison's disease is suspected, blood tests must be performed to measure sodium, potassium and cortisol levels.…”

“…5 Addison's disease is an endocrine disorder characterised by impaired production of hormones from the adrenal cortex leading to increased secretion of adrenocorticotrophic hormone (ACTH). 5,8 Increased ACTH levels can induce proliferation of melanocytes and melanin secretion, causing hyperpigmentation in the skin and mucous membranes. Other common symptoms include fatigue, loss of appetite and weight, weakness and hypotension.…”

“…Low sodium, high potassium or low cortisol level may indicate Addison's disease. 8 Interestingly, oral lesions often precede the cutaneous manifestations, emphasising the dentists' importance in the early diagnosis of the disease. These lesions mainly affect the lips, buccal mucosa, gingiva, palate and tongue.…”

A rare case of oral melanoacanthoma

“…These hormonal effects may enhance the proliferation and activation of melanocytes causing melanocytic hyperplasia and deposition of melanin. [6] In the present case, the patient's hematological examination reports did not reveal any hormonal abnormality.…”

Clinical and histopathological study of the oral multifocal melanoacanthoma: A case report

“…Melanocytic nevus exhibits nevus cell proliferation, a characteristic not found in OMA (2,4). This increase in melanin deposition could also be attributed to Addison’s disease, hyperparathyroidism and the McCune-Albright and Peutz-Jeghers syndromes (8,9). However, our patient presented no associated change of a systemic order.…”