Clinicopathological study of regressed testicular tumors (apparent extragonadal germ cell neoplasms).

Purpose: Testicular germ cell tumors sometimes regress spontaneously and manifest exclusively by metastasis. We report our experience with extragonadal germ cell tumors of probable testicular origin to study the frequency of this entity, and clinical, ultrasound and histopathological correlations in a series of patients.

Materials And Methods: A retrospective 16-year review of 1.2 million inhabitants in Spain revealed 17 with regressed testicular tumors treated at a total of 4 institutions. We analyzed clinical information, ultrasound features and histopathological characteristics of testicular lesions and metastasis, and highlight the main findings.

Results: A primary testicular origin was confirmed in all cases. This entity is more common than initially suspected since it accounts for 4% of consecutive germ cell tumors. Clinical manifestations varied according to metastatic site with an abdominal palpable mass (47% of cases), loin pain (35%) and transient testicular pain (29%) the most common complaints. No evidence of testicular neoplasms was found on physical examination in any case. Metastasis histology was nonseminomatous in 53% of cases, pure seminoma in 29% and mixed in 18%. The most common ultrasound features were calcifications in 65% of cases, hyperechogenic linear images in 59% and hypoechogenic nodular areas in 41%. Histological findings consisted of fibrotic areas in 100% of cases, hemosiderin deposits in 65%, seminiferous tubule atrophy in 59% and psammoma bodies in 29%. In testicular parenchyma or spermatic chord intratubular neoplasms and viable tumor foci were also noted (47% and 41% of cases, respectively).

Conclusions: Spontaneous regression of a germ cell testicular tumor should be considered in each patient with extragonadal germ cell neoplasms. Ultrasound diagnosis of and surgical treatment for these primary testicular tumors appear critical to prevent relapse because residual disease develops in a significant proportion of cases.