Primary testicular lymphoma with subcutaneous masses as the sole manifestation of the first relapse and central nervous system lymphoma as the second relapse: A case report and literature review.

Primary testicular lymphoma (PTL) accounts for ~1% of all non-Hodgkin's lymphomas and has a marked tendency for systemic relapse. The current study presents a unique case of testicular diffuse large B-cell lymphoma of non-germinal center B-cell subtype, with subcutaneous masses as the sole manifestation of the first relapse and central nervous system lymphoma as the second relapse. Subcutaneous relapse and subsequent brain relapse are extremely rare signs of PTL dissemination. The patient received methotrexate-based combined chemotherapy and achieved a partial response. This case presents a rare pattern of treatment failure in this malignant clinical entity.