Gastric crystal-storing histiocytosis detected with asymptomatic Sjögren's syndrome: report of a case and summary.

Crystal-storing histiocytosis (CSH) localized to the stomach is very rare, with only two cases reported to date. The present patient was a 55-year-old woman with no noteworthy symptoms. An area of discoloration was seen in the greater curvature of the gastric body on upper endoscopy by a local physician, and CSH was strongly suspected on biopsy examination. On upper endoscopy performed at our hospital, a flat, whitish, finely granular membrane with a diameter of 10 mm was seen in the greater curvature of the gastric body on white light observation. On magnifying endoscopy of the focal site, white granular material could be seen in the subepithelium, and the surface layer microvascular architecture image seen below the mucosal subepithelium was similar to the background, suggesting localization of the white material in a deep mucosal layer. On endoscopic ultrasound, this was depicted as multiple hyperechoic spots within the second layer corresponding to the involved area. Endoscopic submucosal dissection (ESD) was performed for a definitive diagnosis. Histopathological assessment of resected specimens revealed infiltration of abundant histiocytes including acidophilic crystalline structured material and positive plasma cells on anti-κ chain immunostaining, and CSH was diagnosed. Since this patient could have had a concomitant background autoimmune or hematologic disease, a systemic search was done. During this search, comorbid Sjögren's syndrome was discovered. This case of asymptomatic Sjögren's syndrome discovered during investigation of very rare gastric CHS is reported.