以疼痛性睪丸腫脹類似副睪炎表現之混合型睪丸生殖細胞腫瘤病例報告

吳昊勳¹、陳生文^1,2、張彰琦^1,2、程威銘^1,2、邱逸淳^2,3

¹臺北市立聯合醫院忠孝院區外科部泌尿科

²國立陽明交通大學醫學院

³臺北市立聯合醫院陽明院區外科部泌尿科

A Mixed Testicular Germ Cell Tumor Presenting as Painful Epididymo-orchitis in a Young Man: A Diagnostic Pitfall

Hao-Hsun Wu ¹, Sheng-Wen Chen ^1,2, Chang-Chi Chang ^1,2, Wei-Ming Chen ^1,2, Yi-Chun Chiu ^2,3

¹ Division of Urology, Department of Surgery, Zhongxiao Branch, Taipei City Hospital

² National Yang Ming Chiao Tung University, School of Medicine, Taipei, Taiwan

³ Division of Urology, Department of Surgery, Yangming Branch, Taipei City Hospital

Introduction:

Testicular germ cell tumors (TGCTs) are the most common solid malignancies in young adult males and account for the vast majority of testicular cancers. Classically, TGCTs present as a painless, unilateral testicular mass or induration discovered incidentally by the patient or during routine examination. Pain is reported in only a minority of cases and, when present, is often attributed to associated intratumoral hemorrhage or infarction rather than to inflammatory pathology. In contrast, acute scrotal pain in young men is more commonly ascribed to benign conditions such as epididymitis, orchitis, or testicular torsion. Here, we report a case of a testicular germ cell tumor presenting with testicular pain and initially misdiagnosed as epididymitis.

Case presentation:

A 26-year-old man with no significant past medical history and no relevant family history presented with a chief complaint of left testicular swelling and pain. He denied fever, nausea, vomiting, dysuria, or other lower urinary tract symptoms. Physical examination revealed erythema and swelling of the left hemiscrotum; the left testis was soft but tender on palpation, and Prehn’s sign was positive. He was initially diagnosed with epididymitis at a local clinic and treated empirically with antibiotics; however, his symptoms did not improve. Over the subsequent months, the left testicular swelling and pain progressively worsened. Urinalysis and urine culture were repeatedly negative. Scrotal ultrasonography demonstrated a heterogeneous mass lesion in the left testis. Serum tumor markers were markedly elevated, with alpha-fetoprotein (AFP) 1206 ng/mL, β-human chorionic gonadotropin (β-hCG) 3.0 mIU/mL, and lactate dehydrogenase (LDH) 244 U/L. Pelvic magnetic resonance imaging (MRI) revealed an approximately 10.8 × 8.4 × 7.0 cm heterogeneous intratesticular mass with cystic and hemorrhagic changes within the left scrotum, as well as severe left-sided varicoceles (Figure 2). Subsequent whole-body computed tomography (CT) showed no enlarged mediastinal or para-aortic lymph nodes and no evidence of distant metastasis.

The patient underwent radical inguinal orchiectomy of the left testis. Grossly, the resected specimen contained a 9.5 × 5.0 × 4.5 cm intratesticular tumor (Figure 2). Histopathological examination confirmed a mixed germ cell tumor composed of approximately 25% embryonal carcinoma, 35% choriocarcinoma, and 40% teratoma. The identified epididymis was normal in appearance and free of tumor involvement. The surgical margin of the spermatic cord, including the vas deferens, was negative for malignancy. Postoperatively, serum tumor markers declined substantially to AFP 159 ng/mL, β-hCG 0.1 mIU/mL, and LDH 169 U/L. The pathological staging is pT1N0M0S1, stage IS. The patient subsequently attended the reproductive medicine clinic for sperm banking and underwent implantation of a testicular prosthesis. In accordance with contemporary guideline recommendations, he initiated adjuvant chemotherapy with a bleomycin, etoposide, and cisplatin (BEP) regimen and completed the first cycle without significant adverse effects. He is scheduled to complete the remaining planned chemotherapy courses with regular outpatient follow-up.

Discussion:

In the present case, several clinicopathologic factors may explain why a typically painless testicular germ cell tumor presented with testicular pain and was initially misdiagnosed as epididymitis. The tumor was large at diagnosis (10.8 × 8.4 × 7.0 cm on MRI) with heterogeneous cystic and hemorrhagic changes, suggesting rapid growth with intratumoral hemorrhage, necrosis, and acute expansion of the testicular parenchyma. The resulting rise in intratesticular pressure and stretching of the tunica albuginea is a plausible source of pain and can closely mimic an acute inflammatory process. The predominance of embryonal carcinoma and choriocarcinoma, both aggressive and prone to hemorrhage, may have further contributed to this painful enlargement. In addition, severe ipsilateral varicoceles indicated venous congestion, which may produce a dull, aching scrotal pain that is clinically difficult to distinguish from epididymo-orchitis. Although the erythema, swelling, and positive Prehn’s sign supported an initial impression of epididymitis, the subsequent finding of a normal, tumor-free epididymis suggests these signs were reactive to the intratesticular neoplasm rather than due to primary infection. Collectively, these features underscore that testicular malignancy should remain in the differential diagnosis even when acute scrotal pain and apparent epididymal tenderness are present.

Conclusion:

This case illustrates that testicular germ cell tumors (TGCTs) may present with atypical features that closely resemble benign scrotal conditions and thereby cause diagnostic delay, even when the initial management strategy is reasonable. In clinical practice, the combination of testicular pain, erythema, swelling, and even fever, together with ultrasonographic findings suggestive of epididymo-orchitis, often supports a provisional diagnosis of infection and justifies an empirical course of antibiotics. Our case, however, underscores the need for a structured re-evaluation: even when a benign inflammatory etiology is favored, patients with a testicular mass presumed to be epididymo-orchitis should undergo careful clinical and ultrasonographic reassessment within 2–4 weeks after completing appropriate antibiotic therapy, particularly if symptoms persist, worsen, or fail to fully resolve. At every stage, TGCT should remain an active consideration rather than a distant alternative.

This is especially important in tumors containing choriocarcinoma components, which have a higher propensity for early hematogenous dissemination and thus a greater risk of rapid systemic progression if diagnosis and definitive treatment are delayed. In such patients, both timely recognition with prompt primary treatment and meticulous, guideline-based post-treatment surveillance are essential to detect early relapse and optimize long-term outcomes.