Rapid Disappearance of Testicular Plasmacytoma after Treatment with Lenalidomide plus Dexamethasone

Abstract

We describe a rare case of testicular plasmacytoma first manifesting as a relapse. The patient was initially diagnosed with IgG-λ-type multiple myeloma and treated with melphalan and prednisolone plus bortezomib, achieving a complete remission. Four months later, his left scrotum began to swell and pathological investigation of a needle biopsy specimen revealed proliferation of plasma cells expressing IgG-λ, confirming myeloma recurrence. However, bone marrow aspiration samples showed no significant increase in myeloma cells and there was no skewed deviation of the   ratio on flow-cytometric analysis. The extramedullary tumors disappeared completely soon after treatment with lenalidomide plus dexamethasone, and the patient was judged to be in very good partial remission based on negative M-protein results by serum immunoelectrophoresis. This is the first report, to our knowledge, describing complete disappearance of a testicular plasmacytoma after treatment with lenalidomide as the key-drug.

A Case of Recurrent Multiple Myeloma as Testicular Plasmacytoma Without Systemic Disease

“…Testicular plasmacytoma is highly uncommon and estimated to account for 0.03-0.1% of all testicular malignancies or 2% of all plasma cell neoplasms [ 7 , 8 ]. One study noted that the median age of patients was 51 years and higher than that of testicular cancer [ 9 ]. It was also reported that the majority of the patients demonstrated previous or simultaneous occurrences of MM and plasmacytoma [ 9 ].…”

“…One study noted that the median age of patients was 51 years and higher than that of testicular cancer [ 9 ]. It was also reported that the majority of the patients demonstrated previous or simultaneous occurrences of MM and plasmacytoma [ 9 ].…”

“…The hypothesis of the mechanism of action is that lenalidomide may have an antiproliferative effect on myeloma cells irrespective of its existence in bone marrow stroma or other tissue microenvironments [ 12 ]. Additionally, lenalidomide has a potent anti-tumor activity through anti-angiogenic effects, and prior bortezomib treatment does not affect its response [ 9 ]. Calvo-Villas et al noted that three out of 11 patients demonstrated re-lapse; thus, newer strategies were needed to overcome treatment resistance of the disease [ 11 ].…”

“…EMP usually responds well to local radiotherapy. For testicular plasmacytoma, orchiectomy, followed by chemotherapy or radiotherapy, EMP is considered a therapeutic option [9][10][11]. One possible hypothesis for recurrence in the testicular site is the lack of penetration of bortezomib through the blood-testis barrier, which makes the testis a more likely site for disease recurrence.…”