Testicular Seminoma and Its Mimics:From the Radiologic Pathology Archives

Abstract

Testicular seminoma is the most common malignant tumor of the testis. It classically manifests as a painless mass. Radiologic evaluation with high-frequency ultrasonography (US) is critical for diagnosis. Seminomas are usually homogeneously hypoechoic masses at US. In challenging cases, magnetic resonance (MR) imaging may help confirm that a mass is intratesticular and provide data for local staging. Computed tomography (CT) provides valuable information for staging, including the presence and size of retroperitoneal lymph nodes. Testicular seminoma is treated with radical inguinal orchiectomy and is highly curable even at advanced stages of disease. Several neoplastic and nonneoplastic conditions may mimic testicular seminoma at imaging. Benign mimics include segmental infarction, hematoma, infection, epidermoid cyst, adrenal rests, sarcoidosis, splenogonadal fusion, and sex cord-stromal tumors. Malignant mimics include nonseminomatous germ cell tumors, lymphoma, and metastases. These conditions are individually reviewed with emphasis on features that allow differentiation from seminoma. Spermatocytic tumor, formerly known as spermatocytic seminoma, accounts for only 1% of testicular tumors. It is distinct from classic seminoma, with unique histologic, molecular, and genetic features. It affects an older patient population than classic seminoma and demonstrates indolent clinical behavior. Radiologists serve a key role in diagnosis, staging, and surveillance of patients with seminoma. A thorough knowledge of related clinical, radiologic, and pathologic findings will help the radiologist contribute to high-quality interdisciplinary care of affected patients.

Metastatic Seminoma in a Male Alpine Goat: Clinical and Histopathological Approach

“…Ultrasound assessment showed testicular enlargement, parenchyma loss, presence of masses, cysts, echogenicity, echotexture, and intra-testicular and extra-testicular lesions. According to Marko et al [5], seminomas, under gray-scale US, are hypoechoic compared with the background testis, tend to be homogeneous, and may be lobulated or multinodular, as in our US findings. Even though US cannot be considered as a conclusive diagnostic, it may help to reach a prognosis by the tumor's characteristics.…”

“…Seminoma has been described in species including dogs, horses, humans and rams with a distinct macroscopic presentation in each case [1,2,5,8]. The present findings are the second ever seminoma reported in goats, and particularly this case presented liver metastasis, showing the pathologic potential of this neoplasia for this species, and it differed from those reported previously [6] who described ulcerative lesions in, and adhesion of the skin covering the testis.…”

“…Seminomas are germ cell tumors mainly originating from spermatogonia in the seminiferous tubules and are characterized by spherical or polyhedral neoplastic cells [4,8]. Seminoma has been described in several domestic animal species [1,2,8] and in humans [5]. Nevertheless, in goats, only a single case was reported previously [6].…”

Overview of ultrasound applications for assessing scrotal disorders

“…Typically, they occur unilaterally and vary in size. On native B‐mode US imaging, seminomas appear as homogeneous and hypoechoic lesions compared to the adjacent testicular parenchyma (Figure ) . They may be multinodular or lobulated and may show calcifications and hypervascularization on color Doppler imaging (Figure ).…”

“…Non‐Hodgkin B‐cell lymphoma is the most frequent testicular malignancy in patients older than 60 years, which is typically unilateral and usually painless (Figure ) . The testicular manifestations of lymphomas and leukemias present on US images as unifocal or multifocal hypoechoic and hypervascularized lesions . Adenocarcinoma of the prostate is the most common primary cancer metastasizing to the testicles .…”