Esophageal metastasis from prostate cancer: Diagnostic use of reverse transcriptase-polymerase chain reaction for prostate-specific antigen

An extremely rare case of esophageal metastasis from prostate cancer is reported. A 65-year-old man presented with anorexia and back pain. Upper gastrointestinal X-ray fluoroscopy and endoscopy revealed a shallow longitudinal ulcer, with converging mucosal folds, approximately 5 cm above the esophagogastric junction. The histological diagnosis of the biopsied specimen was adenocarcinoma. Blood biochemistry revealed elevated serum prostatespecific antigen (PSA) and γ-seminoprotein levels. Ultrasonography of the prostate disclosed a hypoechoic lesion in the left lobe, and needle biopsy led to the diagnosis of prostatic adenocarcinoma. Since there was no finding suggestive of a primary lesion, apart from that in the prostate, we conducted reverse transcriptase-polymerase chain reaction (RT-PCR) for PSA. PSA-positive mRNA was demonstrated in the tissue of the esophageal tumor. There are three reports on metastasis to the esophagus from prostate cancer, but this is the first case of esophageal metastasis from prostate cancer without any evidence of metastasis to other organs. The importance of RT-PCR for the diagnosis of primary lesions of metastatic cancer is discussed.