DOG1 is useful for diagnosis of KIT-negative gastrointestinal stromal tumor of stomach

Approximately 80%-95%of gastrointestinal stromal tumors(GISTs)show positive staining for KIT,while the other 5%-20%show negative staining.If the tumor is negative for KIT,but is positive for CD34,a histological diagnosis is possible.However,if the tumor is negative for KIT,CD34,S-100,and SMA,a definitive diagnosis is often challenging.Recently,Discovered on GIST-1(DOG1)has received considerable attention as a useful molecule for the diagnosis of GIST.DOG1,a membrane channel protein,is known to be overexpressed in GIST.Because the sensitivity and specificity of DOG1 are higher than those of KIT,positive staining for DOG1has been reported,even in KIT-negative GISTs.KITnegative GISTs most commonly arise in the stomach and are mainly characterized by epithelioid features histologically.We describe our experience with a rare case of a KIT-negative GIST of the stomach that was diagnosed by positive immunohistochemical staining for DOG1 in a patient who presented with severe anemia.Our findings suggest that immunohistochemical staining for DOG1,in addition to gene analysis,is useful for the diagnosis of KIT-negative tumors that are suspected to be GISTs.

Clinicopathological evaluation of duodenal well-differentiated endocrine tumors

AIM:To assess the clinicopathological characteristics of duodenal well-differentiated endocrine tumors.METHODS:We examined clinicopathological characteristics in 11 consecutive patients with duodenal well-differentiated endocrine tumors treated by endoscopic therapy or surgery in our hospital from 1992 through 2007.Patients with well-differentiated endocrine tu-mors of the papilla of Vater or with gastrinoma were excluded.RESULTS:Three patients received endoscopic treatment,and 8 underwent surgery.In patients who received endoscopic treatment,the tumor diameter was less than 1.0 cm,with no histopathological evidence of lymphovascular invasion or invasion of the muscularis.There were no complications such as late bleedingor perforation after treatment.Among 8 patients with tumors less than 1.0 cm in diameter,3 underwent partial resection,and 2 underwent radical surgery.Three patients had lymphovascular invasion,1 had invasion of the muscularis,and 1 had proximal lymph node metastasis.Among 3 patients with tumors 1.0 cm or more in diameter,1 underwent partial resection,and 2 under-went radical surgery.One patient had lymphovascular invasion,with no lymph node metastasis.After treatment,all patients are alive and have remained free of metastasis and recurrence.CONCLUSION:Duodenal well-differentiated endocrine tumors less than 1.0 cm in diameter have a risk of lym-phovascular invasion,invasion of the muscularis,and lymph node metastasis,irrespective of procedural prob-lems.

Argon plasma coagulation for superficial esophageal squamous-cell carcinoma in high-risk patients

AIM: To evaluate the usefulness and safety of argon plasma coagulation (APC) for superficial esophageal squamous-cell carcinoma (SESC) in high-risk patients. METHODS: We studied 17 patients (15 men and 2 women, 21 lesions) with SESC in whom endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and open surgery were contraindicated from March 1999 through February 2009. None of the patients could tolerate prolonged EMR/ESD or open surgery because of severe concomitant disease (e.g., liver cirrhosis, cerebral infarction, or ischemic heart disease) or scar formation after EMR/ESD and chemoradiotherapy. After conventional endoscopy, an iodine stain was sprayed on the esophageal mucosa to determine the lesion margins. The lesion was then ablated by APC. We retrospectively studied the treatment time, number of APC sessions per site, complications, presence or absence of recurrence, and time to recurrence.RESULTS: The median duration of follow-up was 36 mo (range: 6-120 mo). All of the tumors were macroscopically classified as superficial and slightly depressed type (0-Ⅱc). The preoperative depth of invasion was clinical T1a (mucosal cancer) for 19 lesions and clinical T1b (submucosal cancer) for 2. The median treatment time was 15 min (range: 10-36 min). The median number of treatment sessions per site was 2 (range: 1-4). The median hospital stay was 14 d (range: 5-68 d). Among the 17 patients (21 lesions), 2 (9.5%) had recurrence and underwent additional APC with no subsequent evidence of recurrence. There were no treatment-related complications, such as bleeding or perforation. CONCLUSION: APC is considered to be safe and effective for the management of SESC that cannot be resected endoscopically because of underlying disease, as well as for the control of recurrence after EMR and local recurrence after chemoradiotherapy.