Histological changes in the pituitary gland and adenomas following radiotherapy

To elucidate histological changes in the pituitary gland and adenomas following radiotherapy, two irradiated pituitary glands and seven irradiated non‐functioning adenomas were studied. The latter included four cases with conventional radiation (CR) and three cases with radiosurgery: two with gamma knife radiosurgery (GKR) and one with stereotactic fractionated radiotherapy (SRT). The specimens were obtained 10 months to 10 years (mean 58 months) after the radiotherapy. Irradiated pituitary glands showed diffuse fibrosis in the adenohypophysis, whereas irradiated adenomas showed either mild or no fibrosis in five CR/SRT cases and diffuse thick hyaline deposits in two GKR cases. No necrosis was observed. Stellate‐shaped S‐100 protein‐positive cells were greater in number in the irradiated pituitary glands than in the normal glands. Pituitary cells with dense granular reactivity for mitochondrial protein, cytochrome oxidase, and Mn‐SOD, mimicking oncocytes, were greater in number in the irradiated adenohypophysis but did not show any change in cell size. Many irradiated pituitary cells and some irradiated adenoma cells were densely positive with anticytokeratin 1,5,10,14 antibody whereas non‐irradiated counterparts were negative. In adenomas, MIB‐1 labeling index remained unchanged after the radiation. The results may indicate that radiation‐induced fibrosis was associated with an increased number of folliculo‐stellate cells, mitochondrial dysfunction, and squamous metaplasia. These findings were prominent in irradiated pituitary cells and may participate in delayed pituitary hypofunction following radiotherapy. In irradiated adenoma cells, similar findings were observed but diffuse fibrosis was absent. The histological changes were more intensive in adenomas following GKR than those following CR.     

Electron microscopic observations of blood vessels in ependymoma

The findings of an ultrastructural study of the blood vessels and their surrounding structures in ependymoma are demonstrated. Six surgically removed cases of ependymoma are investigated. The lumen of the blood vessels, especially in vascular rosettes is often wider than those of normal brain capillaries. The endothelial cells are structurally varied, but sometimes attenuated in many areas. Also, they often have several fenestrations. Moreover, they have increased pinocytotic vesicles and filaments, and contain occasional Weibel-Palade bodies, multivesicular bodies and other cytoplasmic organelles. The perivascular space is often wide, especially in intraspinal ependymoma, and filled with multiple layers of basal laminae permeated by electron, dense fluids. There are also collagenous fibers and Luse bodies. Basal lamina covering tumor cell surfaces is more distinct than other basal laminae. The tumor cells facing the blood vessel interestingly show structures similar to those of astrocytic vascular feet. The fenestration in the endothelial cells probably has an important role in the increased vascular permeability of ependymoma.     

A type of adult polyglucosan body disease

Summary Polyglucosan bodies in the nervous system and other viscera are the main findings at autopsy of a 64-year-old woman who had a chronic neurologic disorder of 20 years' duration. The clinical features included muscle weakness, sensory disturbances, neurogenic bladder, dementia, and cataracts. Light and electron microscopy of the nervous system showed numerous polyglucosan bodies in the processes of neurons and astrocytes but not in neuronal perikarya. A similar clinico-pathologic presentation has been described in six previous cases. It is suggested that this is a type of adult polyglucosan body disease which probably forms a variant of Lafora's disease.