病例报告：一例人类免疫缺陷病毒阴性老年女性鼻窦浆母细胞性淋巴瘤，经免疫组织化学诊断。

文献信息

中文摘要

背景： 浆母细胞性淋巴瘤是一种罕见的、高度侵袭性的成熟B细胞淋巴瘤，具有终末B细胞/浆细胞分化特征。它通常发生于人类免疫缺陷病毒感染或其他形式免疫缺陷患者的口腔，而原发性鼻窦受累在表面免疫功能正常的患者中不常见。在苏木精-伊红染色检查中，其组织形态学可能类似于低分化上皮性、黑素细胞性及其他血液淋巴系统恶性肿瘤，因此需要广泛的免疫组织化学组合才能明确诊断。
病例介绍： 一名75岁女性，表现为1个月来进行性左侧鼻塞和清水样鼻溢，就诊前12天有一次鼻出血发作，以及嗅觉减退。她无人类免疫缺陷病毒感染、器官移植或全身性免疫抑制病史。前鼻镜检查显示一个肿物占据左侧鼻腔。增强计算机断层扫描显示一个不均匀强化、局部破坏性的软组织病变，占据左侧上颌窦，并延伸至左侧筛窦、额窦和左侧鼻腔，伴有纸样板和上颌窦壁侵蚀。活检显示高级别恶性圆形细胞/浆母细胞性肿瘤，伴广泛坏死。主要形态学鉴别诊断包括鼻窦未分化癌、非角化性鳞状细胞癌、无色素性黑色素瘤、非霍奇金淋巴瘤和浆细胞肿瘤。免疫组织化学显示CD38、CD138和MUM1强而弥漫表达；PAX5核表达强但局灶；白细胞共同抗原和Epstein-Barr病毒局灶阳性；kappa轻链限制性；Ki-67增殖指数为98%-99%。肿瘤细胞对CD20、全细胞角蛋白、AE1/AE3、S100、人类疱疹病毒8和lambda轻链阴性。最终诊断为浆母细胞性淋巴瘤。患者接受了CHOP化疗（环磷酰胺、多柔比星、长春新碱和泼尼松），截至5个月随访时，已按21天间隔完成三个周期，鼻塞减轻，总体症状改善。治疗后影像学资料不可获得；因此，无法评估放射学和代谢反应。
结论： 本病例强调，即使对于人类免疫缺陷病毒阴性的老年患者，也需将浆母细胞性淋巴瘤纳入侵袭性单侧鼻窦肿物的鉴别诊断，并强调广泛的免疫组织化学组合及轻链评估在解决与其他高级别鼻窦恶性肿瘤形态学重叠中的决定性作用。

英文摘要

BACKGROUND: Plasmablastic lymphoma is a rare, highly aggressive mature B-cell lymphoma with terminal B-cell/plasma-cell differentiation. It usually arises in the oral cavity in patients with human immunodeficiency virus infection or other forms of immunodeficiency, whereas primary sinonasal involvement in an apparently immunocompetent patient is uncommon. On hematoxylin-and-eosin examination, it may histomorphologically resemble poorly differentiated epithelial, melanocytic, and other hematolymphoid malignancies, necessitating a broad immunohistochemical panel for definitive diagnosis.
CASE PRESENTATION: A 75-year-old woman presented with a 1-month history of progressive left-sided nasal obstruction and watery nasal discharge, one episode of epistaxis 12 days before presentation, and reduced olfaction. She had no history of human immunodeficiency virus infection, organ transplantation, or systemic immunosuppression. Anterior rhinoscopy showed a mass occupying the left nasal cavity. Contrast-enhanced computed tomography demonstrated a heterogeneously enhancing, locally destructive soft-tissue lesion occupying the left maxillary sinus with extension into the left ethmoid and frontal sinuses and left nasal cavity, with erosion of the lamina papyracea and maxillary sinus walls. Biopsy showed a high-grade malignant round-cell/plasmablastic neoplasm with extensive necrosis. The main morphologic differentials included sinonasal undifferentiated carcinoma, non-keratinizing squamous cell carcinoma, amelanotic melanoma, non-Hodgkin lymphoma, and a plasma-cell neoplasm. Immunohistochemistry showed strong, diffuse expression of CD38, CD138, and MUM1; strong but focal nuclear PAX5 expression; focal leukocyte common antigen and Epstein-Barr virus positivity; kappa light-chain restriction; and a Ki-67 proliferation index of 98%-99%. Tumor cells were negative for CD20, pancytokeratin, AE1/AE3, S100, human herpesvirus 8, and lambda light chain. A final diagnosis of plasmablastic lymphoma was rendered. The patient received CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone) and had completed three cycles at 21-day intervals by the 5-month follow-up, with reduced nasal obstruction and overall symptomatic improvement. Post-treatment imaging was unavailable; therefore, radiological and metabolic response could not be assessed.
CONCLUSION: This case highlights the need to include plasmablastic lymphoma in the differential diagnosis of an aggressive unilateral sinonasal mass, even in a human immunodeficiency virus-negative elderly patient, and emphasizes the decisive role of a broad immunohistochemical panel with light-chain assessment in resolving morphologic overlap with other high-grade sinonasal malignancies.