A case report of prostate cancer metastasis to the stomach resembling undifferentiated-type early gastric cancer

Abstract

BackgroundOccurrence of metastatic cancer to the stomach is rare, particularly in patients with prostate cancer. Gastric metastasis generally presents as a solitary and submucosal lesion with a central depression.Case presentationWe describe a case of gastric metastasis arising from prostate cancer, which is almost indistinguishable from the undifferentiated-type gastric cancer. A definitive diagnosis was not made until endoscopic resection. On performing both conventional and magnifying endoscopies, the lesion appeared to be slightly depressed and discolored area and it could not be distinguished from undifferentiated early gastric cancer. Biopsy from the lesion was negative for immunohistochemical staining of prostate-specific antigen, a sensitive and specific marker for prostate cancer. Thus, false initial diagnosis of an early primary gastric cancer was made and endoscopic submucosal dissection was performed. Pathological findings from the resected specimen aroused suspicion of a metastatic lesion. Consequently, immunostaining was performed. The lesion was positive for prostate-specific acid phosphatase and negative for prostate-specific antigen, cytokeratin 7, and cytokeratin 20. Accordingly, the final diagnosis was a metastatic gastric lesion originating from prostate cancer.ConclusionIn this patient, the definitive diagnosis as a metastatic lesion was difficult due to its unusual endoscopic appearance and the negative stain for prostate-specific antigen. We postulate that both of these are consequences of hormonal therapy against prostate cancer.

A rare case of PSA-negative metastasized prostate cancer to the stomach with serum CEA and CA19-9 elevation: a case report

“…However, the IHC analyses of the resected tumor revealed that tumor was positive for other markers of prostate cancer, such as AMACR, prostate-specific acid phosphatase (PSAP), androgen receptor, and ERG, suggesting that the tumor was not primary gastric cancer but a metastatic lesion of prostate cancer. There was only one previous case of metastatic gastric metastasis of prostate cancer, which was negative for PSA, similar to our case [12], suggesting that PSA staining was not enough to differentiate the prostate cancer from other cancers. Also, these cases suggest that it is important to perform IHC of the preoperative biopsy sample with multiple markers when the metastatic cancer cannot be denied based on the medical history.…”

“…Metastatic gastric tumor of prostate cancer is rare and only 13 cases have been reported to date [2][3][4][5][6][7][8][9][10][11][12][13][14]. Time to metastasis to the stomach from a diagnosis of primary prostate cancer varies (identified simultaneously to 10 years later).…”

“…Among other cancers, bone and the lung are the most common distant metastatic sites in prostate cancer, which is rarely observed in the stomach/bowel (1.8%) [2]. Thirteen cases of metastatic prostate cancer to the stomach were reported in the English literature to date [3][4][5][6][7][8][9][10][11][12][13][14]. Most were diagnosed by biopsy with immunohistochemistry (IHC) of prostatespecific antigen (PSA), but only one case diagnosed as primary gastric cancer because of negative PSA staining was resected endoscopically [12].…”

“…Thirteen cases of metastatic prostate cancer to the stomach were reported in the English literature to date [3][4][5][6][7][8][9][10][11][12][13][14]. Most were diagnosed by biopsy with immunohistochemistry (IHC) of prostatespecific antigen (PSA), but only one case diagnosed as primary gastric cancer because of negative PSA staining was resected endoscopically [12]. The reported case had prostate cancer with bone metastasis as same as our case, but his serum prostate-specific antigen (PSA) level was high (7040 ng/ml) before treatment [12], which is inconsistent with the finding in our case.…”

Gastric adenocarcinoma mimicking a submucosal tumor: A case report

“…When an SMT-like lesion is encountered in clinical practice, we should consider the possibility of GC and carefully differentiate it from other submucosal lesions, such as gastric neuroendocrine tumors (GI-NETs)[5], smooth muscle tumor, stromal tumor, and lipoma; heterotopic pancreas; and other unusual cases, such as metastatic carcinoma[6], gastric glomus tumor[7],and gastric hamartomatous inverted polyp[8]. According to available reported cases of GC presenting as SMT, the pathologic diagnosis varies including gastric adenocarcinoma[9], gastric mucinous adenocarcinoma[10,11], and gastric lymphoepithelioma-like carcinoma[12].…”