The term pseudolymphoma without modification should be reserved for idiopathic cases. Localized, nodular pseudolymphomas are more common and typically mimic B cell lymphoma. It should be noted that there are a variety of specific diseases that are sometimes referred to as pseudolymphomas, simply because they may resemble lymphoma. These disorders often show broad patches and plaques and often mimic cutaneous T- cell lymphoma. In pseudolymphoma, lymphocytes and other inflammatory cells are recruited to the skin in response to known or unknown stimuli.
Most cases are idiopathic.
A discrete subset of pseudolymphoma, borrelial lymphocytoma, is seen primarily in Europe in areas endemic for the tick Ixodes ricinus. It is a response to infection by Borrelia burgdorferi subsp afzelius conferred by tick bite. Another subset of pseudolymphoma is the result of an unusual systemic response to medications, typically anticonvulsants. See Drug-induced Pseudolymphoma Syndrome . Localized variants rarely result in morbidity other than minor pain or pruritus.