Crystal-storing histiocytosis associated with lymphoplasmacytic lymphoma mimicking Weber-Christian disease: immunohistochemical, ultrastructural, and gene-rearrangement studies.

A case of crystal-storing histiocytosis associated with lymphoplasmacytic lymphoma is presented. Unlike previous cases, this patient presented with signs and symptoms suggestive of Weber-Christian disease. Biopsy of subcutaneous nodules showed numerous deposits of crystal-storing histiocytes with lymphoplasmacytic cells, the latter exhibiting light chain restriction (lambda-chain) with a predominance of immunoglobulin (Ig)G heavy chain. Polymerase chain reaction (PCR) analysis of CDR-II* region of the immunoglobulin heavy chain locus confirmed monoclonality of the lymphoplasmacytic cells in the nodule. Electron microscopy showed polygonal-shaped amorphous crystals, characteristic of immunoglobulin in the histiocytic cells. Crystal-storing histiocytosis should be examined by immunohistochemical and DNA analysis to confirm or exclude the possibility of lymphoplasmacytic lymphoma.