Lymphomatoid papulosis in a patient with Waldenström's macroglobulinemia.

Lymphomatoid papulosis (LyP) is a rare skin disease with a benign course but a malignant histologic appearance based on atypical lymphocytes. Waldenström's macroglobulinemia (WM) is a diffuse infiltration of the bone marrow by cells that synthesize IgM immunoglobulins. A 46-year-old female presented with a two year history of weakness, fatigue, anemia, and recurring multiple erythematous papules and nodules in the skin. The skin biopsy showed pleomorphic lymphoid cells with atypical mitoses permeated by a diffuse dermal infiltrate of normal appearing lymphocytes. The neoplastic cells were positive for CD30, CD3, and CD5 but negative for CD20 and EMA. The bone marrow was hypercellular due to a diffuse infiltration by lymphocytes, plasma cells, and plasmacytoid lymphocytes. LyP is a lymphoproliferative disorder of CD30-positive T cells that may be associated with other lymphoid malignancies, particularly Hodgkin's disease, mycosis fungoides, and anaplastic T cell lymphomas. To our knowledge, this is the first report of a LyP appearing in a patient with WM.