Lambda-Restricted Crystal-Storing Histiocytosis of Stomach: A Case Report and Review of Literature.

Crystal-storing histiocytosis (CSH) is a rare tissue phenomenon that is usually associated with lympho-proliferative diseases. The disease is characterized by prominent collections of macrophages with abundant eosinophilic cytoplasm and fibrillary cytoplasmic inclusions. The inclusions appear as linear crystals within the macrophages which are usually kappa restricted. The disease usually involves lungs, lymph nodes, bone marrow, thymus and spleen with rare involvement of the gastrointestinal tract. We report a rare case of lambda-restricted CSH of the stomach. The diagnosis of CSH triggered further hematological evaluation. The patient was later diagnosed to have diffuse large B-cell lymphoma involving lymph nodes and bone marrow. He received chemotherapy for the same and is on regular follow up. The index case highlights the need to identify CSH of stomach prompting evaluation for hematological malignancies and to increase its awareness among clinicians and pathologists.