[Seminal vesicle cyst and ipsilateral renal agenesis: frequent association].

Presentation of a new case of cyst of the seminal vesicle in one patient with ipsilateral renal agenesis, stressing the frequency of this association. The cyst become evident following confirmation of renal agenesis, and presented an unusual communication to the bladder due to previous surgery (transurethral resection). This diagnosis was only suspected in the computerized tomography and cystoscopy and later confirmed by deferentovesiculography. The relevance of exploring any possible dysplasia of the seminal tract in the presence of renal agenesis is stressed. From an embryological point of view, the close relationship during development of both urinary and reproductive systems appear to explain the coexistence of these two anomalies. The primary symptoms of the condition, including the unspecific ones, as in the present cases, are discussed. Differential diagnosis from other deep pelvic cysts is referred. Following a literature review and based in our personal experience, already published, our views on the different embryological, clinical, diagnostic and therapeutic considerations are established.