The paratesticular region: histoanatomic and general considerations.

The paratesticular region includes the testicular collecting system, the testicular tunics, and spermatic cord. For the purpose of discussion in this issue, the rete testis is also considered part of the paratestis, although it is principally intratesticular in location. The embryologic origins of the paratesticular components and their detailed anatomic and histologic features are presented to provide a background to better understand the pathologic processes affecting the paratestis. A wide variety of cysts, hyperplasias, neoplasms, and tumor-like conditions may affect the paratesticular region, at times resulting in challenging problems in differential diagnosis. An approach to the paratesticular causes of an intrascrotal mass lesion is presented.