Acute myocarditis is a well-known complication of influenza infection. The frequency of myocardial involvement in influenza infection varies widely, with the clinical severity ranging from asymptomatic to fulminant varieties. The worst cases can result in death due to impaired cardiac function, although such fulminant myocarditis associated with influenza infection is rare, as shown by previous papers. Following the 2009 influenza pandemic, we reported on the clinical features of a cohort of 15 patients in Japan with H1N1pdm2009 myocarditis. In our subsequent survey of the literature for case reports or series of patients with myocarditis associated with H1N1pdm2009, we identified 58 detailed cases. We discuss here the high prevalence of fulminant myocarditis (36/58, 62%) among patients reported to have myocarditis associated with H1N1pdm2009. Mechanical circulatory support was required in 17 of the patients with fulminant myocarditis, 13 of whom recovered. We stress the need for increased awareness of influenza-associated myocarditis; such knowledge will facilitate earlier diagnosis and treatment of this fatal complication during future influenza pandemics.

BackgroundCell lines are very useful for both clinical and basic research. The establishment of ovarian, malignant tumor cell lines with aggressive histology is especially important. We describe the establishment and characterization of a new human clear cell carcinoma cell line of the ovary.ResultsThe cell line HCH-1 was established from an ovarian tumor from a 67-year-old woman. This cell line has grown well for 230 months and has been subcultured more than 50 times. Monolayer cultured cells are polygonal in shape, showing a pavement-like arrangement and a tendency to pile up without contact inhibition. It exhibits a human karyotype with a modal chromosomal number in the hypodiploid range. The cells could be transplanted into the subcutis of SCID mice and produced tumors resembling the original tumor. HCH-1 cells produced CA125 and CA19-9, also identified immunohistochemically in both the original tumor and the heterotransplanted tumors. The cells were sensitive to actinomycin D, carboplatin, cisplatin and mitomycin C, drugs commonly used in the treatment of gynecological cancers. Variant was not found in hotspot of the 50 most commonly reported oncogenes and tumor suppressor genes. Only 12 ovarian clear cell carcinoma cell lines and their characteristics have thus far been reported in the literature. HCH-1 is the first ovarian clear cell carcinoma cell line reported in which the chromosome number is in the hypodiploid range and only the second cell line in which CA125 and CA19-9 are expressed.ConclusionsSince it is impossible to establish a cell line from the malignant tumor of each patient, the cell line that we established, characterized and report in this paper may be very useful in basic research on ovarian cancer. We have much to learn about the pathogenesis of clear cell carcinoma and this extra line of enquiry may lead us to a better understanding of how to treat and cure this serious disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13048-016-0242-y) contains supplementary material, which is available to authorized users.

Plasmacytomas are a localized proliferation of plasma cells in the bone marrow and soft tissue. Extramedullary plasmacytomas are rare and typically solitary plasma cell neoplasms originating from extraosseous organs and tissues. A 31-year-old woman was referred to our hospital with a rapidly growing abnormal shadow on a chest roentgenogram. Chest computed tomography showed that the lesion was located in the anterior mediastinum. She underwent surgery, and the tumor was diagnosed as an extramedullary plasmacytoma. She remains well 2 years postoperatively without recurrence. An extremely rare case of an anterior mediastinal extramedullary plasmacytoma is presented.

Background Paragangliomas are rare neuroendocrine tumors originating from chromaffin cells of extra-adrenal origin. Ninety percent of adrenergic tumors originate in the adrenal medulla and are known as pheochromocytomas; the remaining 10% are extra-adrenal and are called paragangliomas. Mediastinum paragangliomas is rare and commonly originate from the posterior mediastinum, while those originating from the middle posterior are quite rare. Some paragangliomas secrete catecholamines, leading to symptoms such as hypertension, tachycardia, and diabetes. Case presentation A 76-year-old woman visited our hospital for the treatment and further evaluation of diabetes. Her hemoglobin A1c levels had risen to 11.0%. To investigate the cause of her diabetes, a contrast-enhanced chest computed tomography scan was performed, revealing a ring-enhancing tumor (30 × 30 mm) in the middle mediastinum. The surgical resection was performed via video-assisted thoracic surgery. Surgery was performed using a vessel-sealing device; however, bleeding was persistent from the surrounding tissue. Total bleeding was 400 g. Blood pressure fluctuations and arrhythmia did not occur during the operation. The patient’s uncontrolled diabetes was cured after the surgery, and the tumor was diagnosed as a functional paraganglioma. Conclusions We encountered a rare case of functional paraganglioma located in the middle mediastinum. Functional paragangliomas should be considered as a potential cause of uncontrolled diabetes, and a whole-body CT scan should be performed to investigate this possible cause.

A 61‐year‐old woman without significant medical history developed fever 3 days after severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) vaccination and went into shock the next day. She was negative for SARS‐CoV‐2 mRNA in real‐time polymerase chain reaction (PCR). Finally, she died 10 days after vaccination. At autopsy, the heart showed moderate dilatation of both ventricles, and the myocardium showed an uneven color change and decreased elasticity. Histologically, severe myocarditis with extensive myocytolysis was observed. The myocarditis showed severe inflammatory cell infiltration with T‐lymphocyte and macrophage predominance, and in addition to the inflammatory cells described above, vast nuclear dust accompanying neutrophilic infiltration was observed. In the bone marrow and lymph nodes, hemophagocytosis was observed. In postmortem examination, nucleic acids of any cardiotropic viruses including SARS‐CoV‐2 were not detected using multivirus real‐time PCR system. We discussed the relationship between the possible immune reaction after vaccination and the myocarditis observed in this case from immunopathological viewpoints. This mRNA vaccine is the first applied nucleic acid vaccine for humans, and its mechanism of efficacy and immune acquisition remain unclear. We hope the accumulation of more detailed analyses of the similar cases to reveal the mechanism of this kind of adverse reaction.