Pulmonary crystal-storing histiocytoma in a patient without a lymphoproliferative disorder

Pulmonary crystal-storing histiocytoma is a very rare disorder and is characterized by infiltration of histiocytes with intracytoplasmic accumulation of crystallized immunoglobulins. It is usually associated with lymphoproliferative diseases or plasma cell dyscrasia. Here, we report a case of pulmonary crystal-storing histiocytoma in a 64-year-old man, presenting as a chronic pulmonary consolidation in the lung exposed to asbestos. Video-assisted thoracoscopic surgical biopsy displayed sheets of large, epithelioid histiocytes filled with a large number of needle-like crystals, showing the accumulation of crystallized polyclonal immunoglobulins. This lesion was consistent with crystal-storing histiocytosis or crystal-storing histiocytoma. With extensive clinical work-up, the current case was not associated with lymphoproliferative diseases. Herein, we present this extremely rare entity of pulmonary pathology, a pulmonary crystal-storing histiocytoma arising in the lung exposed to asbestos, and demonstrate the clinical, radiologic, and pathologic features of the tumor.