Abstract
A 46-year-old Japanese man with a solitary cutanous nodule on the nose came to our attention. The lesion had first appeared 3 years before. The cutaneous lesion was an erythematous nodule, approximately 13×12mm in diameter. Histologically, there was a grenz zone in the upper dermis, and nodular and sheet-like proliferation of lymphoid cells with dense infiltration of large eosinophilic cells (- 30mμ in diameter) at the periphery. The lymphoid cells were positive for CD20, CD79a, bcl-2 and CD43. As the cytoplasms of the large cells were PAS-positive, diastase resistant, they were Mott cells having many Russell bodies in the cytoplasm with displaced nuclei to the periphery. The large cells were negative for CD20, and positive for IgA and κ-chain. The polymerase chain reaction method using DNA extracted from a paraffin section showed a rearranged band of the IgH gene. As further investigations did not demonstrate any visceral manifestations, he has been diagnosed as having primary cutaneous marginal zone B-cell lymphoma.[Skin Cancer (Japan) 2010 ; 25 : 168-172]
