Stratifying the risk of lymph node metastasis in undifferentiated-type early gastric cancer

AIM:To study how lymph node metastasis(LNM) risk is stratified in undifferentiated-type early gastric cancer(undiff-EGC) dependent on combinations of risk factors.METHODS:Five hundred and sixty-seven cases with undiff-EGC undergoing gastrectomy with lymphadenectomy were examined retrospectively.Using clinicopathological factors of patient age,location,size,an endoscopic macroscopic tumor form,ulceration,depth,histology,lymphatic involvement(LI) and venous involvement(VI),LNM risk was examined and stratified by conventional statistical analysis and datamining analysis.RESULTS:LNM was positive in 44 of 567 cases(7.8%).Univariate analysis revealed > 2 cm,protrusion,submucosal(sm),mixed type,LI and VI as significant prognostic factors and > 2 cm and LI-positive were independent factors by multivariate analysis.In preoperatively evaluable factors excluding LVI,sm and > 2 cm were independent factors.According to the depth and size,cases were categorized into the low-risk group [m and ≤ 2 cm,0%(LNM incidence)],the moderaterisk group(m and > 2 cm,5.6%; and sm and ≤ 2 cm,6.0%),and the high-risk group(sm and > 2 cm,19.3%).On the other hand,LNM occurred in 1.4% in all LI-negative cases,greatly lower than 28.2% in all LI-positive cases,and LNM incidence was low in LInegative cases even in the moderate- and high-risk groups.CONCLUSION:LNM-related factors in undiff-EGC were depth and size preoperatively while those were LI and size postoperatively.Among these factors,LI was the most significantly correlated factor.

Pancreatic cancer secondary to intraductal papillary mucinous neoplasm with collision between gastric cancer and B-cell lymphoma: A case report

BACKGROUND Patients with intraductal papillary mucinous neoplasm(IPMN)have an increased risk of pancreatic and extrapancreatic malignancies.Lymphomas are rare extrapancreatic malignancies,and in situ collisions of early gastric cancer and diffuse large B-cell lymphoma(DLBCL)are even rarer.Here,we report the first case of pancreatic cancer comorbid with in situ collision of extrapancreatic malignancies(early gastric cancer and DLBCL)in a follow-up IPMN patient.Furthermore,we have made innovations in the treatment of such cases.CASE SUMMARY An 81-year-old Japanese female diagnosed with IPMN developed elevated carbohydrate antigen(CA)19-9 levels during follow-up.Because her CA19-9 levels continued to rise,endoscopic ultrasound(EUS)was performed and revealed a suspicious lesion at the pancreatic tail.However,lesions in the pancreas were not found by computed tomography,magnetic resonance imaging,or endoscopic retrograde cholangiopancreatography.To make an exact pathological diagnosis,EUS-guided fine needle aspiration was performed.To our supprise,early gastric cancer was found in preoperative gastroscopy.The gastric cancer was completely resected through endoscopic submucosal dissection before postoperative pathology identified early adenocarcinoma collided with DLBCL.Subsequent EUS-guided fine needle aspiration provided pathological support forthe pancreatic cancer diagnosis, and then laparoscopic distal pancreatectomy andsplenectomy were performed. CA19-9 levels returned to normal postoperatively.CONCLUSION Endoscopic submucosal dissection is appropriate for submucosal lymphomas inpatients intoleratant of chemotherapy. EUS can detect small IPMN-relatedpancreatic tumors.

Molecular Dynamics Study on Mechanical Properties in the Structure of Self-Assembled Quantum Dot

Stress and strain in the structure of self-assembled quantum dots constructed in the Ge/Si(001) system is calculated by using molecular dynamics simulation. Pyramidal hut cluster composed of Ge crystal with {105} facets surfaces observed in the early growth stage are computationally modeled. We calculate atomic stress and strain in relaxed pyramidal structure. Atomic stress for triplet of atoms is approximately defined as an average value of pairwise (virial) quantity inside triplet, which is the product of vectors between each two atoms. Atomic strain by means of atomic strain measure (ASM) which is formulated on the Green’s definition of continuum strain. We find the stress (strain) relaxation in pyramidal structure and stress (strain) concentration in the edge of pyramidal structure. We discuss size dependency of stress and strain distribution in pyramidal structure. The relationship between hydrostatic stress and atomic volumetric strain is basically linear for all models, but for the surface of pyramidal structure and Ge-Si interface. This means that there is a reasonable correlation between atomic stress proposed in the present study and atomic strain measure, ASM.