Spontaneous Complete Regression of Testicular Germ Cell Tumor: A Case Report

Testicular germ cell tumors (TGCTs) may spontaneously regress, making it a diagnostic challenge. We present here a case of 39-year-old African American male with constant abdominal pain radiating into the back. Computed tomography identified bulky retroperitoneal lymphadenopathy. There was no history of testicular trauma. Ultrasonography of right testicle revealed multiple microcalcifications, and a laboratory test indicated elevated beta-hCG and LDH. Patient underwent right orchiectomy, which revealed a grossly well-demarcated white oval lesion (3.1 cm). Histologic examination identified a fibrotic lesion in a background of atrophic parenchyma consistent with scar tissue. The specimen was completely submitted for microscopic evaluation, but neoplasia was not identified. A placental alkaline phosphatase (PLAP) immunohistochemical stain failed to reveal residual germ cell neoplasm in situ. Biopsy of retroperitoneal lymph node identified malignant neoplastic cells expressing PLAP, CD117, CD30, and cytokeratin AE1/AE3. The morphology and immunophenotype were consistent with metastatic germ cell tumor. Spontaneous regression of TGCT is defined as partial or complete tumor disappearance without any treatment. The clinical presentation could be nonspecific. Histologically, tumor regression is indicated by formation of fibrous scar, testicular atrophy, microcalcification, lymphoplasmacytic infiltration, and hemosiderin-phagocytosed macrophages, all of which were present in the current case. However, similar histological features could be identified in testicular ischemia or infraction. Therefore, the diagnosis of complete regression of TGCT is challenging and frequently relies on the present of extragonadal germ cell tumor. In the current case, we reported a spontaneous complete regression of TGCT, supported by a spectrum of histological features and metastasis to retroperitoneal lymph node. Spontaneous regression of TGCT is rare, with less than 150 cases reported in the literature. Since there is a lack of definitive histologic criteria to diagnose complete spontaneous regression of TGCT, when scarring is seen in the testis, additional clinical and imaging evaluation should be followed.