Testicular Lymphoma : Differential
Differential Diagnosis of Testicular Lymphoma: Testicular lymphoma must be distinguished from seminoma, embryonal carcinoma, and chronic orchitis. Clinico-pathologic features favoring lymphoma: older age (usually > 50 years), bilateral involvement, interstitial (intertubular) pattern of infiltration, greater pleomorphism, irregular or cleaved nuclei, amphophilic cytoplasm, absence of germ cell neoplasia-in-situ, no immunoreactivity for OCT3/4, PLAP, and positivity for CD45 and other lymphoid markers. Anaplastic large cell lymphoma in the testis may be confused with embryonal carcinoma. Both are CD30 positive and may show coagulative necrosis. Features favoring embryonal carcinoma: strong positivity for OCT3/4 and cytokeratin and negativity for lymphoid markers and the presence of germ cell neoplasia-in-situ. Chronic orchitis has a heterogenous cell population composed of lymphocytes, neutrophils, plasma cells, and macrophages. It is easily distinguished from the monomorphic atypical lymphoid cells of lymphoma. The image shows a diffuse large B-cell lymphoma of the testis in an elderly patient.