Histological diagnosis of gastric submucosal tumors: A pilot study of endoscopic ultrasonography-guided fine-needle aspiration biopsy vs mucosal cutting biopsy

AIM: To compare the usefulness of endoscopic ultrasonography-guided fine-needle aspiration biopsy(EUS-FNAB) without cytology and mucosal cutting biopsy(MCB) in the histological diagnosis of gastric submucosal tumor(SMT).METHODS: We prospectively compared the diagnostic yield, feasibility, and safety of EUS-FNAB and those of MCB based on endoscopic submucosal dissection. The cases of 20 consecutive patients with gastric SMT ≥1 cm in diameter. who underwent both EUS-FNAB and MCB were investigated.RESULTS: The histological diagnoses were gastrointestinal stromal tumors(n = 7), leiomyoma(n =6), schwannoma(n = 2), aberrant pancreas(n = 2), and one case each of glomus tumor, metastatic hepatocellular carcinoma, and no-diagnosis. The tumors' mean size was 23.6 mm. Histological diagnosis was made in 65.0% of the EUS-FNABs and 60.0% of the MCBs, a nonsignificant difference. There were no significant differences in the diagnostic yield concerning the tumor location or tumor size between the two methods. However, diagnostic specimens were significantly more frequently obtained in lesions with intraluminal growth than in those with extraluminal growth by the MCB method(P = 0.01). All four SMTs with extraluminal growth were diagnosed only by EUSFNAB(P = 0.03). No complications were found in either method.CONCLUSION: MCB may be chosen as an alternative diagnostic modality in tumors showing the intraluminal growth pattern regardless of tumor size, whereas EUSFNAB should be performed for SMTs with extraluminal growth.

Diagnosis of small intramucosal signet ring cell carcinoma of the stomach by non-magnifying narrow-band imaging: A pilot study

AIM: To examine the efficacy of non-magnifying narrow-band imaging(NM-NBI) imaging for small signet ring cell carcinoma(SRC).METHODS: We retrospectively analyzed 14 consecutive small intramucosal SRCs that had been treated with endoscopic submucosal dissection(ESD) and 14 randomly selected whitish gastric ulcer scars(control). The strength and shape of the SRCs and whitish scars by NM-NBI and white-light imaging(WLI) were assessed with Image J(NIH, Bethesda).RESULTS: NM-NBI findings of SRC showed a clearly isolated whitish area amid the brown color of the surrounding normal mucosa. The NBI index, which indicates the potency of NBI for visualizing SRC, was significantly higher than the WLI index(P = 0.001), indicating SRC was more clearly identified by NM-NBI. Although the NBI index was not significantly different between SRCs and controls, the circle(C)-index, as an index of circularity of tumor shape, was significantly higher in SRCs(P = 0.001). According to the receiveroperating characteristic analysis, the resulting cut-off value of the circularity index(C-index) for SRC was 0.60(85.7% sensitivity, 85.7% specificity). Thus a lesion with a C-index ≥ 0.6 was significantly more likely to be an SRC than a gastric ulcer scar(OR = 36.0; 95%CI: 4.33-299.09; P = 0.0009).CONCLUSION: Small isolated whitish round area by NM-NBI endoscopy is a useful finding of SRCs which is the indication for ESD.

Greater omentum gastrointestinal stromal tumor with PDGFRA-mutation and hemoperitoneum

Although gastrointestinal stromal tumor(GIST) occurs generally in the digestive tract,omental GIST is very rare.We report the first case of an adult greater omental GIST with a new platelet-derived growth factor receptor α gene(PDGFRA)-mutation with hemoperitoneum.A 43-year-old man was admitted to our hospital complaining of acute abdominal pain.Abdominal contrast-enhanced computed tomography revealed a huge mass in the right abdominal cavity,and a large accumulation of fluid in the pelvic cavity,suggesting hemoperitoneum.We diagnosed the rupture as an intra-abdominal tumor,and an emergency tumorectomy was performed with resection of the greater omentum.This tumor was located in the distal right side ofthe greater omentum,and showed no continuity with the gastric wall.The tumor occurred primarily in the greater omentum.The resected tumor was about 19 cm × 12 cm × 14 cm in diameter,and weighed 1529 g.Histologically,the tumor was composed of epithelioidshaped cells with high cellularity,and was positive for CD117 and CD34,and negative for S-100,α-smooth muscle actin.The mitosis was 6/50 under high power field.This case showed exon 18 mutation of PDGFRA with 846(Asp to Glu) substitution,848(Asn to Lys) substitution.This is the first report of this PDGFRA mutation in omental GIST,and this might play an important role in the tumorigenesis of this case.Based on these findings,the tumor was diagnosed as high risk GIST primarily occurring in the greater omentum.The patient was treated with imatinib at a dose of 400 mg/d as adjuvant chemotherapy,and has been followed up for 24 mo with no evidence of recurrence.

Histopathological Evidence for Irradiation Angiopathy in Head and Neck Cancer

Objective: To evaluate the incidence of cervical angiopathy caused by radiation therapy for head and neck cancer. Methods: Segments of 57 cervical arteries were obtained during surgery for head and neck malignant tumors and divided into two groups (irradiated group and non-irradiated group) based on the treatment prior to vascular resection. In order to evaluate vascular injury after radiation therapy, we examined the degree of medial atrophy, medial fibrosis, smooth muscle cell (SMC) differentiation in the media and intima, intimal hyperplasia and endothelial cell (EC) injury. Sections of arterial segments were stained with hematoxylin-eosin, Elastica van Gieson and Masson’s trichrome, and immunohistochemistry for α-smooth muscle actin (α-SMA), smoothelin, S100A4 and CD31 in the resected vessels was conducted. Results: The median interval between the completion of radiation therapy and vascular resection was nine months. No significant differences were observed between the two groups in terms of medial atrophy, medial fibrosis and intimal hyperplasia. The ratio of the smoothelin-positive area per α-SMA-positive area in the media and the S100A4-positive proportion in the intima, indicating the degree of differentiation of the medial SMC and dedifferentiation of the intimal SMC, respectively, showed no significant differences, despite the tendency toward a lower smoothelin-positive area per α-SMA-positive area in the media of the irradiated arteries. The EC coverage revealed on CD31 immunohistochemistry was significantly decreased, with mural thrombus adhesion, in the irradiated group. Conclusions: The ECs of small arteries are damaged by irradiation. Although we did not confirm the statistical significance of medial SMC dedifferentiation, a decreased expression of smoothelin tended to be observed in the media of the irradiated arteries. Our findings provide histopathological evidence of irradiation angiopathy in head and neck cancer and may help to improve the surgical safety of microvascular anastomosis and determine the treatment strategy for head and neck tumors.