Colon adenocarcinoma with dome-like phenotype: characteristic endoscopic ultrasonography (EUS) findings.
An 80-year-old man underwent colonoscopy for proctorrhagia. Conventional white-light imaging showed a superficially flat and elevated lesion that appeared to be a submucosal tumor of the sigmoid colon. Chromoendoscopy with Indigo Carmine showed that the margin of the tumor was covered with normal epithelium but that there was a slight depression on its surface. Magnification endoscopy with Crystal Violet staining revealed the amorphous surface structure of the depressed lesion, but the surrounding mucosa showed a normal pit pattern. Endoscopic ultrasonography demonstrated that a hypoechoic mass was located in the submucosal layer, and a biopsy specimen obtained from the surface of the lesion showed evidence of adenocarcinoma. We then performed sigmoidectomy on the patient. Immunohistochemically, the tumor cells were positive for two mismatch repair proteins (MLH1 and MSH2), but in situ hybridization revealed that the specimen was negative for the Epstein - Barr virus. We finally diagnosed the lesion as adenocarcinoma with a dome-like phenotype of the sigmoid colon.
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Wataru
W
Takagi
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Katsumi
K
Yamamoto
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Takahiro
T
Amano
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Aisa
A
Sakamoto
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Yuriko
Y
Otake
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Hirotsugu
H
Saiki
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Hisashi
H
Kondo
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Makiko
M
Urabe
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Kei
K
Takahashi
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Masashi
M
Yamamoto
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Shiro
S
Hayashi
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Sachiko
S
Nakajima
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Tsutomu
T
Nishida
Department of Surgery, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Takamichi
T
Komori
Department of Surgery, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Shunji
S
Morita
Department of Pathology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Shiro
S
Adachi
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Osaka, Japan.
Masami
M
Inada