Crystal-Storing Histiocytosis
Cyril Fisher, MD, DSc, FRCPath
Key Facts
Terminology
Soft tissue aggregate of macrophages containing crystalline material
Etiology/Pathogenesis
In low-grade B-cell lymphomas
Monoclonal gammopathy
Myeloma
Eosinophilic colitis
Treatment of lepromatous leprosy with clofazimine
Clinical Issues
Site: Soft tissue, viscera
Can be generalized
Microscopic Pathology
Sheets of rounded or epithelioid histiocytes
Can be spindled or angulated
Eosinophilic cytoplasm
Clusters of elongated crystals
Lesional cells are CD68(+)
 Crystal-storing histiocytosis involving the lung of a patient with myeloma displays sheets of polygonal or spindled histiocytes that infiltrate inflamed loosely fibrous stroma, separating lung structures  . |
 Higher magnification shows aggregate of large polygonal histiocytes. The eosinophilic cytoplasm is distended by sheaves of crystalline structures  . |
TERMINOLOGY
Abbreviations
Crystal-storing histiocytosis (CSH)
Definitions
Soft tissue aggregate of macrophages containing crystalline material
ETIOLOGY/PATHOGENESIS
Paraneoplastic Phenomenon
In B-cell lymphoreticular neoplasia
Lymphoplasmacytoid lymphoma
Chronic lymphocytic leukemia
Extranodal marginal zone lymphoma
MALT lymphoma
Plasma cell dyscrasias
Monoclonal gammopathy
Myeloma
Mastocytosis
Inflammatory Disease
Eosinophilic colitis
