[Long-term progression-free survival after reduction surgery and postoperative low-dose imatinib administration for multiple liver metastases of duodenal gastrointestinal stromal tumor].

A fifty-six year-old woman visited our institute, suffering from lower abdominal pain. A tumor was palpable in the pelvic cavity, having the diameter of 9.7 cm, as measured by transvaginal ultrasonography (US). Computed tomography and magnetic resonance imaging (MRI) revealed a high contrast-enhancement and the central necrosis of the tumor. Surgical resection was performed, and the tumor was found to have originated in the duodenum. Immunohistochemistry confirmed positive KIT, and the mitotic index was 4 per 50 high power field, so that the final diagnosis was a gastrointestinal stromal tumor of intermediate risk. After two years of observation, multiple liver metastases were found. Hepatectomy was performed as a volume reduction surgery, leaving three small lesions in the remnant liver. Imatinib administration was initiated at 400 mg a day two weeks after the surgery, but was interrupted two weeks later because of severe anorexia and a body weight gain of 7 kg due to the increased ascites and edema. Imatinib was resumed at 200 mg/day after a one-month interval. She has been enjoying relapse-free survival for 8 years since the recurrence was diagnosed. Although neither reduction surgery nor dose reduction of imatinib below 300 mg/day is recommended, there may be a possibility that a smaller tumor might be controlled by a lower dose of imatinib.

[A case of pagetoid carcinoma of the breast in nearly complete response by primary systemic therapy].

A 62-year-old female presented with an erosion of the left nipple. At the preoperative examination, it was diagnosed as a Pagetoid carcinoma with an invasive carcinoma. After primary systemic therapy(weekly paclitaxel/trastuzumab), we performed an operation. The only remaining Paget cell was confirmed in the resected specimen, and no other malignant cells were confirmed. There is no report that the preoperative chemotherapy for the Pagetoid carcinoma with an invasive carcinoma. The patient has had no evidence of recurrence 1. 5 years after the operation.

PTEN is a predictive biomarker of trastuzumab resistance and prognostic factor in HER2-overexpressing gastroesophageal adenocarcinoma.

Poor trastuzumab (Tmab) response of patients with human epidermal growth factor receptor 2-overexpressing gastric or gastroesophageal junction adenocarcinoma (HER2-GEA) is associated with the inhibition of phosphatase and tensin homolog (PTEN) expression. In this multicenter, retrospective observational study, pathological samples of patients with HER2-GEA receiving Tmab-combined chemotherapy were immunohistochemically analyzed for PTEN expression. The primary endpoints were disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). We assessed the effect of conventional chemotherapy and Tmab alone or combined with PI3K pathway inhibitors in vitro in HER2-GEA cells with or without PTEN expression. Twenty-nine and 116 patients were in the PTEN-loss and PTEN-positive groups, respectively. In patients with the target region, DCR was significantly lower in PTEN-loss patients than in PTEN-positive patients (67% and 87%, respectively, p = 0.049). The multivariate analysis demonstrated that PTEN loss was significantly associated with shorter PFS (HR = 1.63, p = 0.035) and OS (HR = 1.83, p = 0.022). PTEN knockdown did not affect the cytostatic effect of 5-FU and cisplatin, whereas Tmab combined with the PI3K/mTOR inhibitor NPV-BEZ235 suppressed PTEN-knockdown cell proliferation. In patients with HER2-GEA, PTEN loss is a predictive biomarker of Tmab resistance and prognostic factor. Molecular-targeted therapy with a PI3K/mTOR inhibitor would be effective for HER2-GEA with PTEN loss.

The Cavitron ultrasonic surgical aspirator with a low amplitude is a useful dissection device for surgical procedures: application to vascular detachment and lymph node dissection.

In surgical procedures, although resection and hemostasis maneuvers have become more efficient through the use of dedicated devices, no dedicated device for the dissecting (detaching) maneuver exists at present. The Cavitron ultrasonic surgical aspirator (CUSA: Integra lifesciences Corporation, NJ, USA) is a device originally used mainly for hepatic parenchyma resection in the gastrointestinal surgical field. Tissue is selectively fragmented by an ultrasonically vibrating chip at the tip of the device. Furthermore, physiologic saline is ejected from the tip and aspirated with the fragmented tissue by the device. By reducing the amplitude of the CUSA to 10-20 %, we have been using the device not only for hepatic parenchyma resection but also for dissection in gastrointestinal surgical procedures in general. Here, we explain the details of the techniques that we routinely use, such as dissection of vessels and lymph nodes in radical operations for gastrointestinal cancer. With the CUSA set at a greatly reduced amplitude, dissection can be performed in consideration of layers, surfaces, and membranes while tissue damage and bleeding are minimized. The device is useful for performing higher quality operations.

Pathogenic mechanisms of intestinal pneumatosis and portal venous gas: should patients with these conditions be operated immediately?

We aimed to histologically observe portal venous gas (PVG)-causing intestinal pneumatosis (IP) and evaluate pathogenic mechanisms and therapeutic strategies, including decisions on whether emergency surgery should be performed. Autopsy was performed in two cases of nonocclusive mesenteric ischemia (NOMI). We directly histologically observed the pathogenic mechanisms of IP caused by gas-producing bacteria and IP considered to be caused by mechanical damage to the intestinal mucosa. IP can be classified hypothetically into the following types according to pathogenesis: (1) infection, (2) rupture (damage) of the intestinal mucosa + increased intestinal intraluminal pressure, and (3) mixed type. In cases of IP caused by gas-producing bacteria or IP associated with intestinal wall damage extending beyond the mucosa to the deep muscular layer, emergency surgery should be considered. However, it is highly possible that patients who test negative for infection with gas-producing bacteria whose intestinal wall damage remains only in the mucosa can be conservatively treated.