Crystal-storing histiocytosis in the gastric: a case report and review of the literature

Abstract Background: Crystal-storing histiocytosis (CSH) is a rare disorder characterized by the accumulation of nonneoplastic histiocytes containing intracytoplasmic crystallized immunoglobulins. Although CSH can occur in a variety of organs, including the bone marrow, lungs, lymph nodes, liver, spleen, and kidney, gastric CSH is very rare. Case presentation: We present a 69-year-old man with localized gastric CSH, presenting as positive fecal occult blood for 2 days. Gastroscopy showed that there was a piece of irregular whitish focus in the big bend of gastric antrum, which was soft and elastic. Histologically, the biopsied gastric mucosa showed chronic inflammation, mild activity with erosion, and a large number of eosinophilic mononuclear cells containing fibrillary crystalloid inclusion in the lamina propria. Immunohistochemically, these crystal-containing cells were positive for CD68/PGM1 and Igk, which revealed that the cells were histiocytes harboring kappa light chain-restricted immunoglobulin crystals. Electron microscopic examination showed that a large number of high electron density particles were found in the cytoplasm of cells, with the crystal structure, different sizes and shapes.Conclusion: Since this entity is rare and unfamiliar, difficulties in diagnosis may arise. We present a case of localized CSH associated with just such an incidental gastric lesion and reviewed the related literature, in order to improve our understanding of it and avoid misdiagnosis.