Burned-Out Testicular Germ Cell Tumor Presenting as Retroperitoneal Lymphadenopathy in a Patient With Cryptorchidism: A Case Report & Review of Literature.

Testicular germ cell tumors are the most common malignancy in young and middle-aged men. Spontaneous primary testicular tumor regression, or testicular tumor burn-out, is a rare clinical phenomenon where extragonadal metastatic lesions are observed concurrently with the spontaneous regression of the primary testicular germ cell tumors. Here, we describe the case of a 36-year-old male who presented to our hospital with left-sided abdominal pain and testicular swelling and was found to have significant retroperitoneal lymphadenopathy on his abdominopelvic CT scan. His testicular ultrasound showed multiple echogenic calcifications through the right testicle consistent with microlithiasis. Biopsy of the retroperitoneal lesion revealed a mixed germ cell tumor of testicular origin composed of embryonal carcinoma and teratoma. The patient received four cycles of bleomycin, etoposide, and cisplatin, followed by retroperitoneal lymph node dissection (RPLND) and radical right testicular orchiectomy. Here, we report the second case of burned-out testicular tumor in a patient with ipsilateral cryptorchidism. Furthermore, we elucidate the etiology, clinical presentation, and diagnostic modalities in burned-out testicular germ cell tumors.