A 12-year-old castrated male Jack Russell Terrier presented with intermittent vomiting. Abdominal ultrasonographic examination detected a thickened stomach wall with a mass measuring approximately 1.5 cm in diameter. Computed tomography revealed a solitary mass measuring approximately 2.1 cm in diameter between the submucosa and muscle layers in the greater curvature the pyloric region of the stomach, and a swelling in the hepatic lymph node. The gastric mass was composed of round neoplastic cells arranged in a diffuse pattern. The neoplastic cells had a round nucleus and a pale abundant cytoplasm. Multinucleated giant cells were often found. Hyalinized eosinophilic material, which did not stain with Congo red and had no affinity for thioflavin T, was also observed. Neoplastic cells were immunopositive for MUM1, CD79a and Ig lambda light chain but negative for CD3, CD20, BLA36, IgG and Ig kappa light chain. Stromal eosinophilic material was positive for Ig lambda light chain. The neoplasm was therefore diagnosed as a gastric plasmacytoma with non-amyloid Ig lambda light chain deposition.

一只 12 岁被阉割的雄性杰克罗素梗出现间歇性呕吐。腹部超声检查发现胃壁增厚，肿块直径约 1.5 厘米。计算机断层扫描显示，在胃大弯、胃幽门区的粘膜下层和肌肉层之间有一直径约 2.1 cm 的孤立性肿块，肝淋巴结肿大。胃肿块由呈弥漫性排列的圆形肿瘤细胞组成。肿瘤细胞具有圆形细胞核和苍白丰富的细胞质。经常发现多核巨细胞。还观察到透明化的嗜酸性物质，它没有被刚果红染色并且对硫代黄素 T 没有亲和力。肿瘤细胞对 MUM1 呈免疫阳性，CD79a 和 Ig λ 轻链，但 CD3、CD20、BLA36、IgG 和 Ig κ 轻链呈阴性。基质嗜酸性物质对 Ig λ 轻链呈阳性。因此，该肿瘤被诊断为具有非淀粉样蛋白 Ig λ 轻链沉积的胃浆细胞瘤。