Xanthogranulomatous gastritis associated with actinomycosis: report of a case presenting as a large submucosal mass

Abstract

Xanthogranulomatous gastritis (XGG) is a rarely encountered condition, and its causative mechanism is still unclear. Given that some types of xanthogranulomatous inflammation (XGI) are associated with pathogens, infection should be considered as a possible cause of XGG. Herein, we report a case of an 86-year-old woman presenting with a large, bleeding lesion resembling a submucosal tumor. Distal gastrectomy was performed, and the surgically resected specimen revealed a mass measuring 6 × 4.5 × 3 cm and appearing yellowish on the cut surface. Histopathological examination revealed a few Actinomyces "sulfur granules" and cellular composition characteristic of XGI, supporting a diagnosis of XGG associated with actinomycosis. Gastric actinomycosis is a rare condition and has not previously been reported in association with XGG, although rare cases of XGI associated with actinomycosis have been documented in other organs.

Keywords: Xanthogranuloma; actinomycosis; stomach.

Figure 1

Findings of upper gastrointestinal endoscopy and computed tomography (CT). A, B. Upper gastrointestinal endoscopy revealed a gastric mass resembling a submucosal tumor with an ulcerated depression on its surface. C. On CT, most of the mass showed low density. D. During the arterial phase of contrast-enhanced CT, the mass displayed slight enhancement. E. During the late phase of contrast-enhanced CT, the mass displayed mild enhancement.

Figure 2

Macroscopic findings. A. The mass resembled a submucosal tumor and measured 6 × 4.5 × 3 cm. B. The cut surface of the mass was almost entirely yellowish. The mass was predominantly situated in the gastric submucosa but extended through the muscular layer nearly to the subserosa.

Figure 3

Microscopic findings. Sections stained with hematoxylin and eosin. A. Low-power view showing the heterogeneous cellular composition of the mass, with numerous faintly stained areas (2.5 ×). B. High-power view of foamy-cell-rich area with multinucleated giant cells known as Touton giant cells (400 ×). C. High-power view of a representative area, consisting of spindle cells mixed with abundant foamy cells and scattered lymphocytes (400 ×). D. High-power view of an area with proliferating spindle cells and infiltrating lymphocytes with few foamy cells (400 ×). E. A “sulfur granule” surrounded by neutrophils (200 ×).