Would you offer radiation therapy for extramedullary testicular masses in the setting of multiple myeloma?

If a patient had a symptomatic plasmacytoma involving the testicle (which I don't think I have ever encountered), not responding to systemic therapy, palliative radiation therapy would be a reasonable modality. I would probably start with a very low dose and assess the response to therapy (2 Gy X 2), to limit the risk that RT will decrease the function of the testicles, namely hormone production. A higher dose could be employed if 4 Gy proves unsuccessful. While there is, to some degree, a "blood-testis barrier" that may limit the penetration of some drugs into portions of the testicles, it is hard to know which myeloma agents are affected and to what degree. Therefore, it would seem most appropriate to reserve RT as a palliative modality s...

Testicular plasmacytoma is a rare entity with seventy-one cases published up to 2008. (Wang et al., PMID 18706213) The majority of these patients present as extramedullary manifestations of multiple myeloma. Testis involvement in myeloma and other hematological malignancies has been hypothesized to be partly attributable to the testes being a sanctuary site. This is particularly important in the case of a solitary plasmacytoma in the testis without evidence of other myelomatous spread throughout the body. Thus, when dealing with testicular plasmacytoma, the distinction between primary testicular extramedullary plasmacytoma versus testicular involvement by multiple myeloma is important given the differences in prognosis and treatment pathway...