Fine Needle Aspiration Diagnosis of a Metastatic Mixed Germ Cell Tumor from a “Burned Out” Testicular Primary with Florid Leydig Cell Hyperplasia

“Burned out” testicular germ cell tumors are rare, representing involuted primary tumors typically discovered during workup for metastatic disease with associated elevated serum tumor markers. Histologically, a hyalinized scar is seen, often with surrounding intratubular germ cell neoplasia. We report a 24 year-old man who presented with a two-month history of cough, dyspnea, and intermittent testicular pain. Ultrasound revealed an irregular, hyperechoic 6 x 5 x 5 mm lesion within the right testis. Chest imaging revealed innumerable pulmonary nodules and diffuse lymphadenopathy. Serum tumor markers were elevated (AFP: 432.9 ng/mL, LDH: 2606 U/L, and β-hCG: 97,575 mIU/mL) and the patient underwent a radical orchiectomy. Upon microscopic examination of the orchiectomy specimen there was a 5 mm circular focus of paucicellular fibrosis surrounded by intratubular germ cell neoplasia and diffuse Leydig cell hyperplasia extensively involving the interstitium. Fine needle aspiration of a left supraclavicular lymph node was performed, revealing a mixed germ cell tumor with components of embryonal carcinoma, seminoma, and choriocarcinoma. Diffuse Leydig cell hyperplasia in the setting of a germ cell tumor is rare, and is thought to be induced by markedly elevated serum β-hCG from a syncytiotrophoblastic component (which can be associated with seminoma, embryonal carcinoma, or choriocarcinoma). To the best of our knowledge, this case represents the first report of “burned out” testicular germ cell tumor with diffuse Leydig cell hyperplasia and subsequent germ cell tumor with mixed elements of seminoma, embryonal carcinoma, and choriocarcinoma diagnosed by fine needle aspiration.