Cutaneous and systemic plasmacytosis: a Chinese case.

Cutaneous and systemic plasmacytosis (CSP) is an exceedingly rare condition arising primarily in patients of Japanese descent. Herein, we describe a patient of mainland Chinese origin suffering CSP. A 49-year-old Chinese male had asymptomatic brownish-red plaques and papules of the face and trunk for 6 years. Physical examination revealed innumerable symmetric red-brownish macules on face and trunk with fewer red-brownish papules scattered among the macules. Chemical analysis revealed hypergammaglobulinemia. Computerized tomography scan discovered some lymphadenopathy in the axillary, paratracheal and pulmonary regions. Histological examination showed focal perivascular and periadnexal infiltrate of mainly plasma cells in the superficial and deep dermis. Immunohistochemical study showed that a great number of the infiltrating cells were CD20-positive. The infiltrated polyclonal plasma cells expressed both kappa and lambda light chains. Topical therapy with tacrolimus 0.1% ointment for 2 months reduced the thickness and pigmentation of the facial skin lesions. The lesions resumed the original appearance 3 weeks after discontinuing the therapy. To the best of our knowledge, this is the first case of CSP from mainland China.