Gastric neuroendocrine carcinoma with positive staining for prostate cancer markers including prostate-specific antigen and alpha-methylacyl-CoA racemase

Abstract

We report a case with prostate cancer and gastric neuroendocrine carcinoma. A 72-year old male presented with a gastric lesion 5 months after radical prostatectomy. The lesion was immunohistochemically positive for PSA, alpha-methylacyl-CoA racemase, synaptophysin, and chromogranin A, but negative for androgen receptor (AR). Differentiating gastric neuroendocrine carcinoma from gastric metastasis of prostate cancer is difficult, as both lesions exhibit similar acinar cell proliferation with prominent nucleoli.1 We discuss the diagnostic process of this case and how AR was a useful specific marker for diagnosing primary gastric neuroendocrine carcinoma.