Mucosa-associated lymphatic tissue lymphoma of the lower lip in a child.

Mucosa-associated lymphatic tissue lymphoma of the lip in a child is a very rare clinical entity whose cause is poorly understood. We describe an 11-year-old boy who presented with a 5-month history of an asymptomatic nodule on the lower lip with the clinical appearance of a benign mucocele. After surgical excision of the lower lip lesion, lymphocyte phenotypic analysis and histologic examination of the specimen disclosed an extranodal marginal zone B-cell lymphoma of mucosa-associated lymphatic tissue type of the buccal minor salivary glands. Mucosa-associated lymphatic tissue lymphoma of the lip may clinically resemble a large mucocele. To prevent a delayed detection of lip mucosa-associated lymphatic tissue lymphoma, an incisional biopsy of large mucous cysts of the oral mucosa before marsupialization is recommended.