Warty gastric cancer with polypoid metastases to the gallbladder and urinary bladder

Mutsushi Matsuyama,^1,2 Kazuo Kato,³ Seiichi Goto,⁴ Suzuko Moritani,⁵ Kazuhiro Sentani,⁶ Makoto Kuroda<sup>7

1</sup>Clinical Laboratory, Hekinan Municipal Hospital, Hekinan, Aichi, ²Department of Cell Biology and Anatomy, Fujita Health University School of Medicine, Toyoake, Aichi, ³Clinical Laboratory, Rousai Hospital, Nagoya, Aichi, ⁴Department of Internal Medicine, Hekinan Municipal Hospital, Hekinan, Aichi, ⁵Department of Advanced Diagnosis, Division of Pathology, National Hospital Organization, Nagoya Medical Center, Nagoya, Aichi, ⁶Department of Molecular Pathology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, ⁷Department of Diagnostic Pathology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Abstract: An 80-year-old man had severe lumbago that was diagnosed as multiple myeloma. He was treated with melphalan, prednisone, and zoledronic acid, with a good response. However, he had severe anemia, and endoscopic examination revealed gastric cancer. He died 3 months later. Autopsy revealed verrucous gastric cancer consisting of numerous polypoid mucosal excrescences that had metastasized to the gallbladder and urinary bladder, showing similar polypoid mucosal lesions. The cancer consisted of poorly differentiated cells (about 85%) and signet ring cells (15%) in the stomach. The cancerous tissue was not associated with a desmoplastic reaction, and the signet ring cells showed a positive reaction to cytokeratin 7 and regenerating islet-derived family member 4 antibodies. The cancer cells had a propensity to proliferate on the mucosal surface of the stomach, gallbladder, and urinary bladder.

Keywords: warty gastric cancer, polypoid metastases, signet ring cells, cytokeratin 7, regenerating islet-derived family member 4