Gastrointestinal stromal tumors (GISTs) arising at sites other than the alimentary tract are rare, and they are called extra-GISTs (EGISTs). We report a case of a large EGIST forming a cyst, probably arising in the mesentery of the transverse colon. A 64-year-old Japanese man presented to a hospital with an abdominal tumor forming a large cyst. Intraoperatively, the tumor was neither present in nor in contact with the alimentary tract. It was present in the mesentery of the transverse colon and was attached to the greater omentum and peritoneum, immediately anterior to the body of the pancreas. The tumor was resected with the spleen and a part of the pancreas. Histological examination of the tumor revealed that it belonged to the high-risk category of cystic EGISTs.
Background and Aims:
The mechanism underlying liver regeneration following partial hepatectomy (PH) is not fully elucidated. We aimed to characterize collagen gene expressing hepatic cells following PH and examine their contribution to liver regeneration.
Approach and Results:
Col‐GFP mice, which express GFP under the control of the collagen gene promoter, were used to detect collagen gene expressing cells following PH. The GFP‐expressing cells were analyzed via single‐cell RNA sequencing (scRNA‐seq). Additionally, Col‐ER Cre/RFP and Col‐ER Cre/DTA mice were utilized to examine the cell fates and functional roles of collagen gene expressing cells in liver regeneration, respectively. The number of collagen gene expressing cells was found to be increased on day 3 and subsequently decreased on day 7 following PH. ScRNA‐seq analysis of sorted collagen gene expressing cells showed that the regenerating liver was characterized by three distinct hepatic stellate cell (HSC) clusters, including one representing classic myofibroblasts. The other HSC clusters included an intermediately activated HSC cluster and a proliferating HSC cluster. Of these, the latter cluster was absent in the CCl4‐induced liver fibrosis model. Cell fate tracing analysis using Col‐ER Cre/RFP mice demonstrated that the collagen gene expressing cells escaped death during regeneration and remained in an inactivated state in the liver. Further, depletion of these cells using Col‐ER Cre/DTA mice resulted in impaired liver regeneration.
Conclusions:
Heterogeneous HSC clusters, one of which was a unique proliferating cluster, were found to appear in the liver following PH. Collagen gene expressing cells, including HSCs, were found to promote liver regeneration.
Epithelioid hemangioendothelioma (EHAE) is a vascular tumor which, due to its rarity, is often misdiagnosed as other hepatic tumors based on radiological characteristics. We herein report a case of EHAE in the liver and the mesentery of the small intestine. A 64-year-old asymptomatic woman was admitted to the hospital due to a hepatic tumor identified using computed tomography (CT). An enhanced CT scan revealed multiple tumors in the liver and a tumor in the mesentery. One of the hepatic tumors and the mesenteric tumor were resected and histologically examined. The two tumors exhibited similar histological characteristics and were diagnosed as EHAE. When multiple tumors are found in the liver, EHAE should be included in the differential diagnosis, as the prognosis of EHAE differs from that of carcinoma or benign tumors.
Programmed death 1 (PD1)/its ligand PD‐L1 concomitant with T cell immunoglobulin and mucin domain‐containing protein 3 (TIM‐3)/its ligand galectin 9 (Gal‐9) and the forkhead box P3 (FOXP3) might be involved in tolerance after liver transplantation (LT). Liver biopsies from 38 tolerant, 19 nontolerant (including 16 samples that triggered reintroduction of immunosuppression [IS] and 19 samples after IS reintroduction), and 38 control LT patients were studied. The expressions of PD1, PD‐L1, Gal‐9, and FOXP3 were determined by immunohistochemical and immunofluorescence (IF) staining. The success period of IS withdrawal was calculated using Kaplan‐Meier curve analysis. Tolerant and control patients exhibited higher PD‐L1, Gal‐9, and FOXP3 levels than nontolerant patients at the moment of triggering IS reintroduction. High expressions of PD‐L1 and Gal‐9 were associated with prolonged success of tolerance (83.3% versus 36.7% [P < 0.01] and 73.1% versus 42.9% [P = 0.03]). A strong correlation between PD‐L1 and Gal‐9 expression levels was detected (Spearman r = 0.73; P ≤ 0.001), and IF demonstrated colocalization of PD‐L1 and Gal‐9 in the cytoplasm of hepatocytes. In conclusion, the present study demonstrated that increased expressions of PD‐L1 and Gal‐9 were associated with sustained tolerance after IS withdrawal in pediatric liver transplantation.
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