Crystal-storing histiocytosis associated with marginal-zone lymphoma.

We report a rare case of crystal-storing histiocytosis (CSH) associated with marginal-zone lymphoma. A 91-year-old woman with a history of breast cancer presented with masses of the posterior neck, right breast, and left upper arm. An enlarging mass of the neck was removed and was histologically diagnosed as CSH, associated with marginal-zone lymphoma. Masses in the breast and upper arm were evaluated by needle biopsy and revealed as CSH. CSH is a rare condition characterized by the intrahistiocytic accumulation of crystallized immunoglobulins, and is associated with disorders in which monoclonal immunoglobulins are expressed. To the best of our knowledge, there are few previous descriptions of CSH which include the imaging features of this disease. In the present case, the masses showed hypoechogenicity with internal patchy hyperechoic areas on ultrasonography, and an iso-signal to slight hyperintensity compared with muscle on T2-weighted magnetic resonance imaging. We report the imaging findings in CSH and discuss their diagnostic implications.