Pediatric primary cutaneous marginal zone lymphoma: in association with chronic antihistamine use.

Primary cutaneous marginal zone lymphoma of the mucosa-associated lymphoid tissue predominantly occurs in adults and is rare in children. There have been no prior reports of this lymphoma occurring in American children. We present a case of a 15-year-old male with a history of atopic diathesis and chronic use of antihistamine agents who presented with an asymptomatic lesion on his left forearm of 6 months duration. Because histopathological and immunohistochemical studies were compatible with marginal zone lymphoma, and the patient had no associated extracutaneous disease, the diagnosis of primary cutaneous marginal zone lymphoma was rendered. Based on the patient's past medical history prior to appearance of lesion, it was postulated that the development of lymphoma was associated with the ingestion of antihistamines and further propagated by his underlying atopic diathesis.