Cystic transformation and calcium oxalate deposits in rete testis and efferent ducts in dialysis patients.

The histological study of the testes and epididymides obtained from autopsies of 24 men with chronic renal insufficiency revealed bilateral cystic transformation of the rete testis and efferent ducts in patients who underwent hemodialysis or peritoneal dialysis, but not in patients who did not receive this treatment. The lesion was associated with an accumulation of crystalline calcium oxalate deposits in the lumen of the rete testis and efferent ducts, and in the connective tissue adjacent to these excretory ducts. The rete testis epithelium showed columnar transformation with occasional papillary proliferations. Neither atypias or mitoses were observed. In three specimens, fibrosis and giant cell reactions was also present in the rete testis at the level of crystalline deposits. In three specimens, the caput epididymidis was enlarged, and the efferent ducts showed an increase in both tubular diameter and epithelial height, irregular outline, and development of diverticula. The lesions appeared within 30 months after the onset of dialysis.