A rare case of metastatic ductal type prostate adenocarcinoma presenting with syndrome of inappropriate secretion of antidiuretic hormone: a case report and review.

Ductal adenocarcinoma of the prostate is a rare malignancy and it accounts for less than 1% of prostatic adenocarcinomas as a predominant pattern. In general, the prognosis for these patients is worse than those with typical adenocarcinoma of the prostate. SIADH is a rare paraneoplastic syndrome associated with classic and poorly differentiated acinar prostate adenocarcinoma. To our knowledge, this is the first case of paraneoplastic SIADH associated with ductal type prostate adenocarcinoma. The case highlights once again that the patients with metastatic prostate cancer who present with hyponatremia should get a diagnostic workup for SIADH done due to the potential fatal consequences of this paraneoplastic syndrome.