Focal rituximab-induced edematous reaction at primary cutaneous follicle center lymphoma lesions: case report and literature review.

Primary cutaneous follicle center lymphoma (PCFCL) is the most common cutaneous B cell lymphoma. It is most often indolent and responds well to rituximab. We present a case of transient rituximab-induced edematous lesions located exclusively on tumor papules in a patient treated for PCFCL. Based on this observation and on a review of the literature, we discuss the mechanism of this edematous reaction which does not seem to be allergic. Indeed, this focal reaction observed solely during the first infusion of rituximab is more likely linked with local cytokine release induced by B cell lysis in the skin. This reaction is neither unusual nor severe and should not lead to an interruption of rituximab.