FINAL DIAGNOSIS:

SERTOLIFORM CYSTADENOMA OF THE RETE TESTIS

DISCUSSION:

Benign epithelial tumors of the rete testis are very rare with only a few cases reported and described as adenoma³, benign papillary tumor⁴, cystadenoma⁵, papillary cystadenoma⁶ and adenofibroma of the rete testis. Jones et al. first described the sertoliform cystadenoma of the rete testis in 1997¹. This is an extremely rare entity, with only four cases reported in the literature^1-2. They occurred in patients between 34 and 62 years presenting as a unilateral painless testicular mass. A single case is reported where the process was an incidental microscopic finding and measured 0.4 cm. A summary of the cases reported in the literature is presented in Table 1.

On gross examination the tumor typically presents as a single well-circumscribed, partially cystic, tan or white mass confined to the region of the rete testis, measuring 1-3 cm. The remainder of the testis, spermatic cord and paratesticular structures are normal. Sertoliform cystadenoma may be mistaken for a Sertoli cell tumor. Gross appearance, growth pattern and more importantly the location of the tumor are essential in distinguishing these two entities (compared in Table 2).

One theory proposes that the site of origin of the sertoliform cystadenoma is from the 'transition zone' between rete and seminiferous tubules. As both structures develop from the same gonadal sex cord germinal epithelium, the cells from the junctional area of the rete may have a potential to develop toward Sertoli cells². The epithelium of the straight tubules provides a connection between the epithelium of the rete and the Sertoli cells of the seminiferous tubules, and ultrastructural similarities between them have been described⁷.

This web case adds new data to the growing literature of benign rete neoplasms, which resemble Sertoli cell tumors. We would like to raise the awareness about the importance of considering this entity in the differential diagnostic of Sertoli cell tumors. The correct diagnosis, especially in a biopsy specimen as in our case, is crucial for the course of treatment. Because a Sertoli cell tumor is a potentially malignant tumor, definitive therapy requires orchiectomy and assessing for possible metastatic disease; in contrast, a sertoliform cystadenoma could be managed by conservative excision and clinical follow-up.