Primary leiomyosarcomas of the gastrointestinal (GI) tract are extremely rare and highly aggressive neoplasms, and only a small number of true cases have been reported since the concept of GI stromal tumors was established. Here, we report a case of a primary leiomyosarcoma of the transverse colon. A 46-year-old Japanese male with a large mass in the right upper abdomen was admitted to our hospital. Computed tomography and magnetic resonance imaging revealed long segments of wall thickening of the transverse colon with large consecutive tumors measuring 12 cm in diameter. A projecting irregular mass with marked mucosal necrosis was found on colonoscopy. Pathological examination revealed a spindle cell tumor growing circumferentially and transmurally to replace the muscularis propria in the transverse colon. The spindle cells were positive for smooth muscle actin, and negative for KIT, CD34, DOG-1, and S-100 protein. The patient has shown repeat recurrence in spite of sufficient surgical excision being promptly performed.

Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is the most common type of autoimmune encephalitis. The disease predominantly affects women (1:5–1:10), with only 3 reports of autopsy findings in women being published to date. The present study reports findings from the first autopsy performed on a man with anti-NMDAR encephalitis. The patient had some scattered lesions in the limbic system with neuronal loss, gliosis, and microglial activation. The temporal and frontal cortices showed additional patchy demyelination. T-lymphocyte infiltration was detectable in the fusiform gyrus lesion. These findings were partly similar to those reported in female patients. Although clinical differences based on the sex of the patient are reported for this disease, the observed pathological similarities potentially help to establish common therapeutic strategies for all patients. Severe testicular damage was additionally observed in the male patient in this study. Biopsy-proven severe testicular damage was also confirmed in another, previously fertile man who became azoospermic. Moreover, serum follicle-stimulating hormone levels, which often increased in response to disturbed spermatogenesis, were elevated, and testosterone/luteinizing hormone ratio reflecting Leydig cell function was low in all 5 male patients in this study. Overall, these findings suggest similar brain pathology in patients of both sexes and severe testicular damage in male patients.

Nemaline bodies were found in the regenerating muscle fibers of the neck of a 74-year-old Japanese male with pharyngeal cancer. Histologically, the nemaline bodies were needle-shaped structures and hematoxophilic with phosphotungstic acid-hematoxylin stain. Electron microscopic examination suggested that they arise as extensions of the Z bands. Although nemaline bodies occur in a variety of pathological conditions other than nemaline myopathy, their occurrence in regenerating skeletal muscle fibers invaded by cancer has not been reported previously. The pathogenesis of the nemaline body formation in the present case is discussed.

Anti-N-methyl-d-aspartate receptor (anti-NMDAR) antibody-associated encephalitis is an immunologic disease characterized by a female preponderance. Males are infrequently affected. The clinical symptoms of affected boys as well as girls have been summarized, and they have some clinical features distinct from those of adults. However, the characteristics of men have been described in only a few reports. We describe in detail four men with anti-NMDAR encephalitis who presented with several clinical features that complicated disease management and recovery, including venous thrombosis, bilateral hippocampal involvement, hypersexuality, and joint contracture. We also report the first detailed clinical information about a male patient who died of this disease. In addition, we summarize the clinical characteristics of five patients previously reported by others.