LMNA Mutation c.917T>G (p.L306R) Leads to Deleterious Hyper‐Assembly of Lamin A/C and Associates with Severe Right Ventricular Cardiomyopathy and Premature Aging

Mutations in the LMNA gene coding for the nuclear lamina proteins lamin A and its smaller splice form lamin C associate with a heterogeneous group of diseases collectively called laminopathies. Here, we describe a 2‐year‐old patient with a previously undescribed phenotype including right ventricular cardiomyopathy, progeroid features, and premature death. Sequencing of LMNA revealed a novel heterozygous de novo mutation p.L306R located in the α‐helical rod domain of A‐type lamins. Fibroblasts from the patient showed reduced proliferation and early premature replicative senescence, as characterized by progressive hyperlobulation of the nuclei, abnormally clustered centromeres, loss of lamin B1, and reorganization of promyelocytic leukemia nuclear bodies. Furthermore, the patient cells were more sensitive to double‐strand DNA breaks. Similar structural and phenotypic defects were observed in normal fibroblasts transfected with FLAG‐tagged p.L306R lamin A. Correspondingly, in vitro assembly studies revealed that the p.L306R generates a “hyper‐assembly” mutant of lamin A that forms extensive fiber arrays under physiological conditions where wild‐type lamin A is still largely soluble. In summary, we report a novel LMNA p.L306R mutation that leads to previously undescribed hyper‐assembly of lamin A, heavy distortion of nuclear shape and that manifests as right ventricular cardiomyopathy and premature aging.     

Extract of Ginkgo Biloba Ameliorates Streptozotocin-Induced Type 1 Diabetes Mellitus and High-Fat Diet-Induced Type 2 Diabetes Mellitus in Mice

Diabetes mellitus (DM) is caused by either destruction of pancreatic β-cells (type 1 DM) or unresponsiveness to insulin (type 2 DM). Conventional therapies for diabetes mellitus have been developed but still needs improvement. Many diabetic patients have complemented conventional therapy with alternative methods including oral supplementation of natural products. In this study, we assessed whether Ginkgo biloba extract (EGb) 761 could provide beneficial effects in the streptozotocin-induced type 1 DM and high-fat diet-induced type 2 DM murine model system. For the type 1 DM model, streptozotocin-induced mice were orally administered EGb 761 for 10 days prior to streptozotocin injection and then again administered EGb 761 for an additional 10 days. Streptozotocin-treated mice administered EGb 761 exhibited lower blood triglyceride levels, lower blood glucose levels and higher blood insulin levels compared to streptozotocin-treated mice. Furthermore, liver LPL and liver PPAR-α were increased whereas IL-1β and TNF-α were decreased in streptozotocin-injected mice treated with EGb 761 compared to mice injected with streptozotocin alone. For the type 2 DM model, mice were given high-fat diet for 60 days and then orally administered EGb 761 every other day for 80 days. We found that mice given a high-fat diet and EGb 761 showed decreased blood triglyceride levels, increased liver LPL, increased liver PPAR-α and decreased body weight compared to mice given high-fat diet alone. These results suggest that EGb 761 can exert protective effects in both type 1 and type 2 DM murine models.     

Nodular smooth muscle metaplasia in multiple peritoneal endometriosis

We report here an unusual presentation of peritoneal endometriosis with smooth muscle metaplasia as multiple protruding masses on the lateral pelvic wall. Smooth muscle metaplasia is a common finding in rectovaginal endometriosis, whereas in peritoneal endometriosis, smooth muscle metaplasia is uncommon and its nodular presentation on the pelvic wall is even rarer. To the best of our knowledge, this is the first case of nodular smooth muscle metaplasia occurring in peritoneal endometriosis. As observed in this case, when performing laparoscopic surgery in order to excise malignant tumors of intra-abdominal or pelvic organs, it can be difficult for surgeons to distinguish the metastatic tumors from benign nodular pelvic wall lesions, including endometriosis, based on the gross findings only. Therefore, an intraoperative frozen section biopsy of the pelvic wall nodules should be performed to evaluate the peritoneal involvement by malignant tumors. Moreover, this report implies that peritoneal endometriosis, as well as rectovaginal endometriosis, can clinically present as nodular lesions if obvious smooth muscle metaplasia is present. The pathological investigation of smooth muscle cells in peritoneal lesions can contribute not only to the precise diagnosis but also to the structure and function of smooth muscle cells and related cells involved in the histogenesis of peritoneal endometriosis.     

Mesothelial cell inclusions in pelvic and para-aortic lymph nodes: a clinicopathologic analysis

Benign lymph node inclusions are commonly encountered during surgery for gynecologic neoplasms and are potential mimics of metastatic tumor. The presence of mesothelial cell inclusions in pelvic lymph nodes is extremely rare. We report the clinicopathologic features of 10 patients with ovarian tumors and mesothelial cell inclusions detected in the sinuses of pelvic and paraaortic lymph nodes. All patients had concurrent massive ascites and mesothelial cell hyperplasia at the time of lymph node dissection. Histologically, nodal mesothelial cells were identified predominantly within the subcapsular, trabecular and medullary sinuses. Moreover, intra- and extranodal lymphatics also contained mesothelial cells, confirming their mode of lymphatic transport to nodal sinuses. This finding, together with mesothelial cell hyperplasia and massive ascites suggest that mesothelial cells derive from reactive serosal mesothelium and are dislodged into draining lymphatics. This study indicated the pathogenic significance of the lymphatic transport mechanism. Nodal mesothelial cell inclusions should be distinguished from metastatic tumor to avoid inaccurate staging in a patient with a known tumor or the false negative diagnosis of an occult primary tumor. Recognition of this entity by immunohistochemical evaluation in addition to routinely stained sections is important to prevent a diagnosis of metastatic carcinoma or malignant mesothelioma.     

Fibromyxoid variant of endometrial stromal sarcoma with atypical bizarre nuclei

Endometrial stromal sarcoma (ESS) is the second most common malignant uterine mesenchymal tumor. It affects women primarily in the perimenopausal age group. ESSs are morphologically heterogeneous. The distinction between uterine smooth muscle tumors such as cellular leiomyoma and myxoid leiomyosarcoma and low-grade ESS can be problematic when stromal sarcomas show prominent smooth muscle differentiation and abundant myxoid stroma, respectively. We herein present a rare case of fibromyxoid variant of ESS, which was misdiagnosed as hydropic leiomyoma on intraoperative frozen section examination. Grossly, the uterine mass consisted of intracavitary and intramural portions. The intracavitary portion with extensive hydropic degeneration mimicked a hydropic leiomyoma. In contrast, the intramural portion displayed an obvious tongue-like myometrial invasion. Histologically, the tumor consisted of both cellular (20%) and myxoid (80%) areas. In the cellular areas, oval to spindle-shaped tumor cells with bland nuclear features were found to surround concentrically a rich vascular network of arterioles, a characteristic of ESS. In addition, two relatively well-circumscribed nodular lesions showing atypical bizarre nuclei were identified in the myxoid area. Immunohistochemically, the tumor cells were diffusely and strongly positive for CD10. The present case indicates a wide morphological spectrum of ESS. Fibromyxoid variant of ESS should be considered in the differential diagnosis of intracavitary and/or intramural uterine mesenchymal tumors with myxoid differentiation. It is important to avoid confusion between fibromyxoid ESS and myxoid leiomyosarcoma because of the differences in their clinical course, treatment, and prognosis.