Sharma Ashish, Binazir Tina, Sintow Alexandre, Lee Chi Chan, Shaharyar Sameer, Tache Jason
Internal Medicine, Aventura Hospital and Medical Center.
Oncology, Westside Regional Medical Center.
Cureus. 2017 Jun 27;9(6):e1400. doi: 10.7759/cureus.1400.
Multiple myelomas (MM) of the immunoglobulin D (IgD) subtype is rare amongst plasma cell malignancies. It can present a diagnostic challenge because of the low amount of immunoglobulin in the serum. The amount of monoclonal (M)-protein is often undetectable on electrophoresis. Historically, survival in these patients was typically shorter compared to the immunoglobulin A (IgA) and immunoglobulin G (IgG) subtypes due to advanced disease upon presentation. With the advent of better diagnostic techniques, the prognosis of this disease is changing. We describe a case of an extramedullary testicular plasmacytoma (EMP) of the IgD subtype as the primary feature of MM, which responded well to novel therapy. A 72-year-old White male presented to the emergency room with a right testicular mass for three months. He subsequently underwent right radical orchiectomy. Pathology of the specimen revealed plasmacytoid cells positive for cluster of differentiation (CD79a), lambda free light chain, IgD, and BCL-1 (Cyclin D1) on immunochemical stains. Urine and serum immunofixation were positive for monoclonal IgD with lambda light chain specificity and Bence Jones proteinuria. Bone marrow biopsy showed large sheets of plasma cells with greater than 90% cellularity. Flow cytometry displayed atypical plasma cells expressing cluster of differentiation (CD38, CD20, and CD56) with cytoplasm and lambda light chain, approximately 20%, consistent with a plasma cell dyscrasia. Stage 3 IgD lambda multiple myeloma was diagnosed. He received novel treatment with Bortezomib and dexamethasone for three months, followed by Lenalidomide. His performance status and lab data improved significantly. He had progression-free survival (PFS) of approximately three years and remained in complete remission low-dose dose of Lenalidomide daily. IgD myeloma was considered a diagnostic challenge due to undetectable M-protein levels on serum protein electrophoresis (SPEP). With the advent of serum free light chain assay and serum and cytologic examinations, diagnostic accuracy has significantly improved. The IgD subtype is commonly associated with poor clinical outcomes. However, the use of novel agents and autologous transplant has changed the prognosis of this disease.
免疫球蛋白D（IgD）亚型的多发性骨髓瘤（MM）在浆细胞恶性肿瘤中较为罕见。由于血清中免疫球蛋白含量较低，它可能带来诊断挑战。在电泳中，单克隆（M）蛋白的量常常无法检测到。从历史上看，由于这些患者就诊时疾病已进展，与免疫球蛋白A（IgA）和免疫球蛋白G（IgG）亚型相比，他们的生存期通常较短。随着更好的诊断技术的出现，这种疾病的预后正在改变。我们描述了一例IgD亚型的睾丸髓外浆细胞瘤（EMP）作为MM的主要特征，该病例对新疗法反应良好。一名72岁的白人男性因右侧睾丸肿块三个月就诊于急诊室。随后他接受了右侧根治性睾丸切除术。标本的病理学检查显示，免疫化学染色中浆细胞样细胞分化簇（CD79a）、游离λ轻链、IgD和BCL-1（细胞周期蛋白D1）呈阳性。尿液和血清免疫固定电泳显示具有λ轻链特异性的单克隆IgD和本周氏蛋白尿阳性。骨髓活检显示大片浆细胞，细胞密度大于90%。流式细胞术显示非典型浆细胞表达分化簇（CD38、CD20和CD56）以及细胞质和λ轻链，约占20%，符合浆细胞异常增殖症。诊断为3期IgD λ多发性骨髓瘤。他接受了硼替佐米和地塞米松的新疗法治疗三个月，随后接受来那度胺治疗。他的身体状况和实验室数据有显著改善。他的无进展生存期（PFS）约为三年，并且通过每日低剂量来那度胺维持完全缓解状态。由于血清蛋白电泳（SPEP）上无法检测到M蛋白水平，IgD骨髓瘤被认为是一个诊断挑战。随着血清游离轻链检测以及血清和细胞学检查的出现，诊断准确性有了显著提高。IgD亚型通常与不良临床结局相关。然而，新型药物的使用和自体移植改变了这种疾病的预后。
