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 literature1-2. 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.

Table 1. Sertoliform rete cystadenoma
Case No. Age Dimension Gross Appearance Reference
1 34 1 cm Cystic mass in the hilum M. Jones et al, J. of Urologic Pathology, 1997
2 59 3 cm Nodular mass E. Jones et al., Seminars in Diagnostic Pathology, 2000
3 62 2.3 cm Solid and cystic mass in the hilum M. Jones et al, J. of Urologic Pathology, 1997
4 N/A N/A Unremarkable E. Jones et al., Seminars in Diagnostic Pathology, 2000

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).

Table 2. Comparison between sertoliform cystadenoma is Sertoli cell tumor
Sertoliform cystadenoma Sertoli cell tumor
Location Centered and confined to the rete testis Mostly in the testicular parenchyma
Growth pattern Non invasive tubular or solid pattern within the channels of the rete Invasive, diffuse sheet-like or nodular pattern
Microscopic characteristics Monotonous and bland Sertoli-like cells filling and distending tubules of the rete testis Cells with lipid droplets or vacuolated cytoplasm
Mitotic figures Absent Variable, usually present

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.


  1. Jones MA, Young RH: Sertoliform rete cystadenoma: A report of two cases. J Urol Pathol 7:47-53, 1997.
  2. Jones EC, Murray SK, Young RH: Cysts and epithelial proliferations of the testicular collecting system (including rete testis). Seminars in Diagnostic Path 4:270-293, 2000.
  3. Nistal M, Jimenez-Heffernan JA: Rete testis dysgenesis: A characteristic lesion of undescended testes. Arch Path Lab Med 121: 1259-1264, 1997.
  4. Trainer D: Testis and extrectory duct system, Sternberg SS (ed): in Histology for Pathologists. New York, Raven Press, 731-747, 1992.
  5. Bustos-Obregon E, Holstein AF: The rete testis in man: Ultrastructural aspects. Cell Tissue Res 175: 1-15, 1976.
  6. Saitoh K, Terada T, Hatakeyama S: A morphological study of the efferent ducts of the human epididymis. Int J Antrol 13:369-376, 1990.
  7. Altafffer L., Dufour D., Castleberry G. and Steele S.: Coexisting rete testis adenoma and gonadoblastoma. J Urol Pathol 127, 332-335.
Contributed by Diana Ionescu, M.D., J. Thomas Molina, M.D., Ph.D., and Sheldon Bastacky, M.D.

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