Given the images appearances, a testicular tumor was sought, particularly seminoma, and the patient was referred to the urology clinic. CT staging of the chest, abdomen and pelvis was unremarkable. Tumor markers were negative.The patient underwent left orchiectomy, which has revealed seminoma. 

Macroscopic description: Left testis: A testis 45 x 32 x 25 mm with spermatic cord 90 mm in length x up to 18 mm in width. The tunica vaginalis is soft and movable. Inked green. In the upper pole of the testis there is a firm white vaguely lobulated tumor 12 mm in maximum dimension. The tumor is clear of the tunica albuginea, the rete testis and the epididymis. The background testis is soft, homogeneous and orange. 

Microscopic description: Sections show testis containing a well circumscribed unencapsulated tumor. The tumor is composed of nests and cords of cells set within a retracted stroma. The malignant cells are large and have irregularly shaped nuclei with coarse chromatin, variably prominent nucleolus, and eosinophilic cytoplasm. The tumor stroma contains a brisk infiltrate of lymphocytes. The tumor is 12 mm in maximum dimension, and well clear of the tunica albuginea, rete testis and epididymis. The surrounding testicular parenchyma shows tubular atrophy and intratubular germ cell neoplasia. The tumor is completely excised, and the spermatic cord margin is clear.

Diagnosis: Left orchiectomy: Seminoma. - 12mm in maximum dimension. - clear of spermatic cord margin. - clear of tunica albuginea, rete testis and epididymis.