We describe a family with an autosomal dominant form of retinal-cerebellar atrophy. There is an extreme variability in age of onset and severity of the clinical symptoms: some patients remain nearly asymptomatic throughout their entire life; others develop severe retinal and cerebellar symptoms after the age of 35 years; others suffer from a severe disorder with onset in adolescence and death during the third decade of life; in others the onset is in early childhood with prevalence of cerebellar symptoms. There is neither dementia nor epilepsy in any of the patients. Four out of five autopsies showed a severe retinal atrophy, and all five autopsies were also characterized by (1) a cerebellar atrophy affecting the spinocerebellar and olivocerebellar tracts, the cerebellar cortex and the efferent cerebellar pathways, (2) an involvement of the pyramidal pathways and of the motor neurons of brain stem and spinal cord, and (3) an atrophy of the subthalamic nucleus and to a much lesser extent of the pallidum, with also some damage to the substantia nigra. The posterior columns are much less affected except in one patient. In this family, we have excluded linkage with the two loci for spinocerebellar ataxia, i.e., SCA1 on chromosome 6p and SCA2 on chromosome 12q as well as with the locus for Machado-Joseph disease (MJD) on chromosome 14q. A genome-wide search is currently being performed to detect the disease locus responsible.

A benign papilloma of the choroid plexus of the left lateral ventricle is found in a five-month old infant. An important dilatation of the isolated occipital horn is observed, without generalized enlargement of the ventricles. The clinical signs are limited to a moderate macrocephaly with deviation of head and eyes to the left. The absence of global hydrocephalus is rather exceptional in such cases, where overproduction of cerebrospinal fluid, in an amount proportional to the tumoral mass, is generally admitted. Nevertheless, the literature offers no absolute proof of the role of oversecretion alone in the origin of hydrocephalus, whilst an eventual obstruction of the circulatory pathways and resorption areas of the C.S.F. must be kept in mind. The absence of hydrocephalus, in the present case, suggests that the subarachnoid spaces and arachnoid villi remained patent.

A non operated aneurysm of the anterior communicating artery enlarged considerably over a seven years period; it finally thrombosed and behaved like a suprasellar tumor. The clinical course, the angiographic evolution and the anatomical examination allowed, in this case, to account for the increase in volume by progressive stretching of the wall, and not by incorporation of a false aneurysmal sack resulting from an encapsulated haematoma. Histologically, the wall of this giant aneurysm showed various changes : on the inner aspect, progressive thickening occurs, due to fibrous organization of mural thrombosis; in the depth, far from the nutrient sources, necrotic atheromatous like foci occur, which isolate an inner leaflet, prone to become nectrotic at a later stage. Distension of such a weakened wall may lead to several consequences; a progressive increase in volume of the aneurysm, partial ruptures with haemodissection starting from the aneurysmal lumen, or even complete rupture of the wall and subarachnoid haemorrhage. On the other hand, circulatory stasis, due to the important increase in volume, may facilitate progressive thrombosis of the aneurysm. The living character of the wall is emphasized by the coexistance of these unfavourable (degeneration, ruptures) and favourable (thrombosis, fibrous organization) features, which continuously influence the spontaneous evolution of the aneurysm.

A 12-year old child and a 2-month old infant developed, in the wane of a purulent meningitis, the former, an infratentorial subdural empyema, the latter, a large, encapsulated, haemoorhagic, aseptic subdural effusion, in the right parieto-temporo-occipital region. In both cases, signs of intracranial hypertension dominated the clinical picture. Neuroradiological investigations permitted diagnosis and localisation of the expansive processes, whose subdural position was recognized at operation and confirmed by histopathological examination. According to the literature, purulent meningitis is a rare cause of subdural empyema, except in infants; the solely infratentorial location is also unusual. Sterile subdural effusion is a more common complication of purulent meningitis in infancy, but the unilateral posterior supratentorial location is also a peculiar feature. Subdural collections after memingitis may be aseptic and possibly haemorrhagic, or septic and purulent; these different modes of presentation correspond perhaps to different degrees or stages of subdural pathological changes in the neighbourhood of leptomeningeal infection.