Objective: To promote the accuracy of diagnosis and the efficiency of treatment of primary epididymal adenocarcinoma.Methods: A 57 years old man was admitted in April 2000 with the right epididymal mass. We treated him as right epididymal neoplasm according to his symptom, physical examination, diagnostic therapy and specific carcinoembryonic antigen about epididymis.Results: The patient suffered a right orchiectomy by transscrotal approach. The pathologic analysis displayed a right adenocarcinoma of the epididymis, grade Ⅱ-Ⅲ with a positive surgical margin of right spermatic cord, and immunohistochemical PSA staining was negative. Then a upper right spermatic cord excision and biopsy of the lymph nodes in pelvic cavity was performed. Intraoperatively, the metastasis disease was found during inguinal exploration. Metastasis or invaded adenocarcinoma was found in right spermatic cord and fibrous tissue based on pathologic examination. No intravascular metastasis was found. No furthermore treatment was given and the patient died half an year after diagnosis.Conclusion: The adenocarcinoma of the epididymis is easily misdiagnosed to be the tuberculosis of the epididymis and chronic epididymitis, and usually the neoplasm was poorly differentiated. The prognosis of these cases are very poor, and usually die in a short term. Objective: To promote the accuracy of diagnosis and the efficiency of treatment of primary epididymal adenocarcinoma. Methods: A 57 years old man was admitted in April 2000 with the right epididymal mass. Weiter him as right epididymal neoplasm according to his symptom, physical examination Diagnostic therapy and specific carcinoembryonic antigen about epididymis. Results: The patient suffered a right orchiectomy by transscrotal approach. The pathologic analysis displayed a right adenocarcinoma of the epididymis, grade II-III with a positive surgical margin of the right spermatic cord, and immunohistochemical PSA staining was negative. Then a upper right spermatic cord excision and biopsy of the lymph nodes in pelvic cavity was performed. Intraoperatively, the metastasis disease was found during inguinal exploration. Metastasis or invaded adenocarcinoma was found in right spermatic cord and fibrous tissue based on pathologic No intravascular metastasis was found. No furthe rmore treatment was given and the patient died half an year after diagnosis. Confound: The adenocarcinoma of the epididymis is easily misdiagnosed to be the tuberculosis of the epididymis and chronic epididymitis, and usually the neoplasm was poorly differentiated. The prognosis of these cases are very poor, and usually die in a short term.