Testicular cancer is the solid tumor with the greatest incidence in men between 15 and 44 years old. Its main histological type is germ cell tumor, that is divided into seminomatous and non-seminomatous tumors. Seminoma, consisting 55% of testicular cancer, manifests in the fourth decade of men's life and a rare type of it is the anaplastic seminoma (5% to 15% of testicular seminoma). Diagnosis is based on clinical examination, testicular ultrasound, magnetic resonance imaging, tumor markers measurement and pathological examination, while treatment of choice is radical orchiectomy, with or without retroperitoneal lymphadenectomy, potentially followed by radiotherapy or chemotherapy. We present the case of a 36-year-old male patient, whose father suffered from anaplastic seminoma and visited the hospital due to a painless hydrocele. The testicle was swollen and hard on palpation, while cytological examination of the drained fluid detected neoplasm, potentially seminoma. Tumor markers measurement, as well as abdominal and pelvic computerized tomography scans, were evaluated and the patient was staged as IIA, according to the American Joint Commission on Cancer. Radical orchiectomy with high ligation of the seminal vesicle was performed and the pathological examination showed anaplastic testicular seminoma. Postoperatively, four cycles of chemotherapy with bleomycin, etoposide and platinum (BEP) were performed and no signs of recurrence were present after 1 year. In conclusion, anaplastic seminoma has a good prognosis and is suggested to be treated with radical orchiectomy, with or without retroperitoneal lymphadenectomy, potentially followed by radiotherapy or chemotherapy.