RESUMEN
<p><b>OBJECTIVE</b>To investigate the clinicopathological characteristics of primary Burkitt's lymphoma (BL) in the spermatic cord.</p><p><b>METHODS</b>A case of BL of the spermatic cord was studied by histopathology and immunohistochemical techniques. The clinical data and the related literature were reviewed.</p><p><b>RESULTS</b>The patient was a 4-year-old boy, who was accidentally found with a bump in the scrotum. Surgery showed it to be a tumor located in the left spermatic cord and 5 cm x 3 cm x 2 cm in size, gray and fish-like on cross-sectional imaging. Histologically, it was characterized by monotonous infiltration of medium-sized cells with round nuclei, coarse chromatin, 2-5 basophilic nucleoli, and an appreciable rim of basophilic cytoplasm, in a typically starry-sky pattern imparted by interspersed tangible-body macrophages. Immunohistochemically, the tumor cells were diffused, positive for CD20 and CD79, some for CD10 and about 95% with the nuclear expression of Ki-67, but negative for CD3, CD43, bcl-2 and TdT as well as for EBER in situ hybridization.</p><p><b>CONCLUSION</b>Primary spermatic cord BL is extremely rare, highly aggressive and with poor prognosis. Diagnosis of the tumor relies on its pathological characteristics and immunohistochemical staining. It is essential to differentiate BL from other types of lymphomas and malignant small-cell tumors of the non-lymphatic system.</p>