Abstract

Paneth cell-rich carcinoma is essentially an adenocarcinoma with a predominance of Paneth cells. A 60-year-old male patient was admitted with a history of abdominal distension for several months. Endoscopic examination revealed a large ulceroinfiltrative tumor involving most of the areas of the stomach. The biopsy of the lesion confirmed poorly differentiated adenocarcinoma and total gastrectomy was followed. The submitted total stomach contained a diffuse infiltrative Borrmann type IV mass with ulceration, 8.0 3.5 cm, at the body along the lesser curvature. Microscopically, it was composed of Paneth cell differentiated cancer cells and poorly differentiated tubular adenocarcinoma cells. The Paneth cell differentiation was characterized by cytoplasmic coarse eosinophilic granules, which were PAS-positive and positive reaction for lysozyme. Electron microscopic examination showed numerous, spherical, electron-dense, homogeneous granules corresponding to those in Paneth cells as well as mucin granules in the signet-ring cells, and various intermediate forms in some cancer cells, which might be immature in the Paneth cell lineage.

• Keywords: Stomach;Carcinoma;Paneth cells