Department of Veterinary Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea.
Naason Science, Inc., Cheongju, Republic of Korea.
Vet Med Sci. 2023 May;9(3):1053-1061. doi: 10.1002/vms3.1086. Epub 2023 Feb 7.
Most extramedullary plasmacytomas (EMPs) aresolitary and located in the head and neck region. They may also occur in the visceral parts of the body.
Here, we report a case of oral EMP followed by neoplastic plasma cell metastasis to both kidneys in a neutered male Pomeranian.
Oral plasmacytoma recurred 11 months aftersurgical removal of an oral mass and partial maxillectomy was performed. Eighteen months after partial maxillectomy, neoplastic masses were detected in both kidneys on computed tomography. The dog died 12 months after detection of bilateral kidney neoplasms. The resected neoplastic masses were routinely processed for histopathological observation and immunohistochemistry against pan-cytokeratin, desmin, CD3, and MUM-1.
The recurred mass mainly consisted of well-differentiated plasma cells and contained a small portion of aggressive cells with malignant features. Monoclonal gammopathy was not observed on serumelectrophoresis performed to exclude multiple myeloma. The mass was composed of plasma cells with high nuclear pleomorphism and abundant mitotic figures. The neoplasm stained positive for MUM-1 with a more aggressive morphology than in oral EMP.
Based on serum biomarker and pathological observations, a diagnosis of recurrence and metastasis of oral-to-renal EMP was established. To the best of our knowledge, metastasis of oral EMP into the bilateral kidneys, as described in the current case, has not been previously reported in dogs.
大多数髓外浆细胞瘤（EMP）为单发，位于头颈部。它们也可能发生在身体的内脏部位。
本文报告了一例雄性博美犬口腔 EMP 继发自发性双侧肾脏浆细胞瘤转移的病例。
口腔浆细胞瘤在口腔肿块切除和部分上颌骨切除 11 个月后复发，再次进行了部分上颌骨切除术。部分上颌骨切除 18 个月后，计算机断层扫描发现双侧肾脏有肿瘤性肿块。在检测到双侧肾脏肿瘤 12 个月后，该犬死亡。切除的肿瘤性肿块常规进行组织病理学观察和针对泛细胞角蛋白、结蛋白、CD3 和 MUM-1 的免疫组织化学染色。
复发性肿块主要由分化良好的浆细胞组成，含有一小部分具有恶性特征的侵袭性细胞。为排除多发性骨髓瘤，对血清进行电泳检查未观察到单克隆丙种球蛋白血症。该肿块由具有高核多形性和丰富有丝分裂象的浆细胞组成。肿瘤对 MUM-1 呈阳性染色，形态比口腔 EMP 更具侵袭性。
根据血清生物标志物和病理观察，诊断为口腔-肾 EMP 的复发和转移。据我们所知，目前病例中描述的口腔 EMP 转移至双侧肾脏在犬中尚未有报道。
