Single-frequency 45-mJ pulses from a MOPA system using an Er,Yb:glass planar waveguide amplifier and a large mode area Er-doped fiber amplifier.

We demonstrate a master oscillator power amplifier (MOPA) system that emits single-frequency high-energy optical pulses at 1540 nm using an Er,Yb:glass planar waveguide amplifier and a large mode area Er-doped fiber amplifier. A double under-cladding and a 50-µm-thick core structure are employed for the planar waveguide amplifier to increase the output energy without degrading the beam quality. A pulse energy of 45.2 mJ with a peak power of 27 kW is generated at a pulse repetition rate of 150 Hz with a pulse duration of 1.7 µs. Moreover, the beam quality factor M2 of the output beam is 1.84 at the highest pulse energy thanks to its waveguide structure.

A case of early gastric cancer resembling a subepithelial lesion diagnosed by endoscopic ultrasound-guided fine needle aspiration.

We present a case of early gastric cancer resembling a subepithelial lesion (GCSEL) derived from the submucosal ectopic gastric glands (SEGGs), diagnosed using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). A 55-year-old woman was referred to our hospital for the investigation of a subepithelial lesion (SEL). Contrast computed tomography and esophagogastroduodenoscopy revealed two SELs in the greater curvature of the fundus and the posterior wall of the upper body of the stomach. EUS revealed a hypoechoic lesion in the submucosa and suggested partial invasion into the muscularis propria of the greater curvature of the fundus, and an anechoic lesion in the submucosa of the posterior wall of the upper body. The different diagnosis for the SEL in the fundus was GCSEL, neuroendocrine tumor, malignant lymphoma, and gastric adenocarcinoma of fundic gland type. EUS-FNA findings suggested adenocarcinoma. The patient underwent a laparoscopic proximal gastrectomy. Pathological findings confirmed a differentiated tubular adenocarcinoma derived from the SEGG, which partially invaded into the submucosa of the surrounding gastric wall without lymphovascular invasion or lymph node metastasis. The patient has been recurrence-free after 10 months of follow-up. EUS should be performed for SELs followed by EUS-FNA for lesions, such as GCSEL, that require early intervention.

[A Case of Fournier's Gangrene during Second-Line IRIS plus Bevacizumab Chemotherapy for Rectal and Anal Canal Cancer].

A 52-year-old man diagnosed with Stage ⅢA rectal and anal canal cancer underwent abdominal perineal resection using Miles's method. Two years later, local recurrence and lung metastases were detected using contrasted CT imaging. First-line chemotherapy of XELOX was administered for 4 months until the disease progressed and lung metastases developed. After 4 courses of second-line IRIS plus bevacizumab chemotherapy, fever and swelling of the right buttock appeared; he visited and was admitted to our hospital. A CT scan revealed a pelvic abscess which resulted in septic shock. Swelling and pain extended to the right scrotum, and acute necrotizing fasciitis was suspected, and emergency surgery was performed. An incision was made from the right buttock to the right scrotum, bloody purulent drainage with a foul odor was observed, and a diagnosis of Fournier's gangrene was made. Although typical CT findings such as emphysema due to gas-producing bacteria were not observed in this case, early diagnosis and intervention of systemic management including early surgical drainage and operation were effective. For pelvic infections occurring during bevacizumab chemotherapy, Fournier's gangrene should considered for differential diagnosis, even if CT findings are atypical.