Testicular Lymphoma: Primary and Secondary Involvement

This chapter explores the testicular involvement of lymphoma. Testicular lymphoma may either represent secondary involvement by systemic disease or primary malignancy. Regarding primary testicular lymphoma (PTL), it is a rare form of extranodal lymphoma and the most frequent malignant testicular neoplasm in men over the age of 60 years. The diffuse large B-cell lymphoma (DLBCL) accounts for the majority of cases. The morphologic manifestation of PTL on imaging may be in the form of a localized mass or a diffuse enlargement of the testis. On ultrasonography, PTL usually appears as a hypoechoic area with hypervascularity. MRI and positron emission tomography with computed tomography (PET/CT) are useful diagnostic tools. The latter is crucial in staging and follow-up of these patients. The treatment of PTL is based on orchiectomy, chemotherapy, and radiotherapy. The prognosis is poor and PTL exhibits a propensity to relapse in the central nervous system (CNS) and in the opposite testis. Secondary involvement of the testis by non-Hodgkin lymphoma (NHL) is more frequent than PTL. Patients may develop the relapsed or refractory disease in the testis in the context of disseminated lymphomas due to the existence of the blood-testis barrier. This chapter discusses the treatment of secondary involvement by lymphoma.