Immunohistochemical localization of autophagosomal membrane-associated protein LC3 in granular cell tumor and schwannoma

Granular cell tumor (GCT) is a neoplasm derived from Schwann cell or (in cases arising in the neurohypophysis) pituicyte and is characterized by abundant cytoplasm filled with numerous eosinophilic granules, which have been considered autophagolysosomes on the basis of their ultrastructure. To confirm that the formation of these granules is related to an autophagy phenomenon, 12 cases of GCT (including two cases of GCT of the neurohypophysis) were studied immunohistochemically using an antibody against LC3 (microtubule-associated protein 1 light chain 3, a specific marker of autophagy). All cases of GCT showed granular immunoreactivity for LC3 in the cytoplasm of tumor cells, indicating that the formation of intracytoplasmic granules in GCT is closely related to an autophagy phenomenon. For elucidation of the relationship between GCT and schwannoma, 20 cases of schwannoma were similarly studied using the anti-LC3 antibody. In eight of 20 cases, a small number of tumor cells showed granular immunoreactivity for LC3, suggesting an increased autophagic activity in some schwannomas and further reinforcing the close relationship between GCT and schwannoma

Anaplastic ependymoma simulating glioblastoma in the cerebrum of an adult

A case of anaplastic ependymoma of the cerebral hemisphere in which the histopathological features closely simulated those of glioblastoma is reported. The patient was a 72-year-old woman with a large, well-demarcated tumor in the left temporal lobe. The tumor was totally extirpated, but recurred 18 months later, and the patient died after 4 months. The extirpated tumor was well circumscribed from the surrounding brain tissue and consisted of a sheet-like, dense proliferation of atypical, short spindle or polygonal cells. Extensive geographic necrosis with nuclear pseudopalisading was seen. Although perivascular pseudorosettes were observed in many areas, true ependymal rosettes were absent. Immunohistochemistry for glial fibrillary acidic protein and epithelial membrane antigen and ultrastructural study confirmed the ependymal nature of tumor cells. The histopathological spectrum of anaplastic ependymoma is very wide and reflects the basically dual characteristics of ependymal cells: epithelial and glial phenotypes. The present case indicates that some anaplastic ependymomas strongly express the glial phenotype and also show remarkable anaplastic cytological features, thus closely simulating glioblastoma. The diagnostic criteria for anaplastic ependymoma, and the nosological position of highly anaplastic ependymoma and its possible clinical implications, are briefly discussed

Extreme deformability of insect cell membranes is governed by phospholipid scrambling

昆虫の細胞は柔らかい！ --細胞膜を柔らかくするタンパク質を発見--. 京都大学プレスリリース. 2021-06-09.Organization of dynamic cellular structure is crucial for a variety of cellular functions. In this study, we report that Drosophila and Aedes have highly elastic cell membranes with extremely low membrane tension and high resistance to mechanical stress. In contrast to other eukaryotic cells, phospholipids are symmetrically distributed between the bilayer leaflets of the insect plasma membrane, where phospholipid scramblase (XKR) that disrupts the lipid asymmetry is constitutively active. We also demonstrate that XKR-facilitated phospholipid scrambling promotes the deformability of cell membranes by regulating both actin cortex dynamics and mechanical properties of the phospholipid bilayer. Moreover, XKR-mediated construction of elastic cell membranes is essential for hemocyte circulation in the Drosophila cardiovascular system. Deformation of mammalian cells is also enhanced by the expression of Aedes XKR, and thus phospholipid scrambling may contribute to formation of highly deformable cell membranes in a variety of living eukaryotic cells

Juvenile granulosa cell tumor of the ovary: Imprint cytology findings

We present here the cytologic findings obtained from imprint smears of a juvenile granulosa cell tumor (GCT) of the ovary, a rare tumor in the sex cord/stromal tumor group that occurs predominantly in children and young adults.4 To our knowledge, the cytologic findings of juvenile GCT have been documented in only one case in the English-language literature.3 A girl aged 6 years, 7 months, presented with spotty vaginal bleeding, enlargement of both breasts and growth of fine pubic hair. A laparotomy disclosed a 10\ua56\ua55-cm, solid tumor replacing the right ovary (FIGO stage Iai). A right salpingo-oophorectomy was performed, and the patient recovered uneventfully. Direct imprint smear specimens were taken from the freshly cut surface of the tumor. The tumor cells formed many large, cellular aggregates with an irregular shape, and single cells were scattered in between (Figure 1). Cellular cohesiveness was of a moderate degree. The nuclei of the tumor cells were large and round or elliptical. Nuclear atypism and pleomorphism were not remarkable. The nuclear contour was smooth, and coffee bean-like nuclear grooves or indentations were not observed (Figure 2). Nuclear chromatin was of moderate amount and finely stippled. A few small but distinct nucleoli were found. The cytoplasm was pale and moderate in amount, and its border was indistinct

A case of rare primary cystic-type squamous cell carcinoma of the breast that could be preoperatively diagnosed

Primary squamous cell carcinoma of the breast (SCCB) is a rare disease, with a worldwide incidenc