We present three cases of primary progressive aphasia (PPA) with Pick-variant pathology to support a hypothesis of an underlying nosologic relatedness. Neuropathologic examination demonstrated focal brain atrophy with corresponding neuronal loss and gliosis, accompanied by superficial spongiosis. Specific histologic findings were ballooned neurons (Pick cells) in the atrophic areas, and in two of the cases, Pick bodies. They were immunoreactive for tau. In contrast to classic Pick's disease, there were no Pick bodies in the hippocampus. The intense neurofilament immunoreactivity of the perikarya of the ballooned neurons greatly facilitated their recognition. Based on our cases and a critical review of the literature, we hypothesize that the common underlying pathology of PPA is a variant of Pick's disease. Furthermore, we propose the concept of "Pick complex" to include other neurodegenerative diseases characterized by focal cortical degeneration, such as PPA, frontal lobe dementia, ALS with PPA, and corticonigral and corticobasal ganglionic degenerations.

Hippocampal sclerosis is the sole abnormality found in approximately 65% of all temporal lobe specimens resected for intractable temporal lobe epilepsy. Up to 27% of en bloc temporal lobectomy specimens, however, show no definitive pathological changes. The lateral amygdaloid nucleus from 8 consecutive patients who underwent temporal lobectomy in whom no definitive hippocampal pathology was present and corresponding tissue from 8 consecutive patients with hippocampal sclerosis were subjected to quantitative estimation of neuronal density and astrogliosis. As compared to amygdaloid tissue from autopsy control subjects with no history of neurological disease, both the patient group with and that without hippocampal sclerosis consistently exhibited severe neuronal loss and gliosis with no quantitative differences between the two groups. Blinded clinical review of both groups of patients revealed that the development of hippocampal sclerosis was associated with a history of early brain insult; this history was absent in patients with isolated amygdaloid sclerosis. Neuropsychological testing prior to surgery demonstrated that patients with hippocampal sclerosis displayed a greater degree of memory impairment than did those without hippocampal sclerosis. We conclude that amygdaloid sclerosis occurs in the absence of hippocampal sclerosis, and that these patients form a distinct group with no history of early brain insult and milder memory impairment than that seen in patients afflicted with hippocampal sclerosis.

Isolated amygdalar sclerosis (AS) in the presence of an intact hippocampus has been described in a subset of patients who have undergone a temporal lobectomy for the relief of seizures. Clinical observation suggested that these patients might be distinguishable, before and after operation, from those with typical mesial temporal sclerosis, which implies combined amygdalar and hippocampal sclerosis (AHS). From a three year series, all 11 patients classified as having AS were included in this study. These patients were compared with a group of 20 randomly chosen patients with AHS. The groups were found to be well matched in duration of ongoing seizures, full scale IQ, and duration of follow up (mean 19 months). Compared with patients with AHS, patients in the AS group were less likely to have had a seizure in early childhood, a variety of auras, EEG abnormalities localised to one temporal lobe, or an abnormkal MRI before operation. They also performed better on preoperative memory tests. At follow up, patients in the AS group were less likely to be seizure free and more likely to have a deterioration in memory after undergoing anterior temporal lobectomy, including part of the hippocampus. The results show that there are preoperative indicators of mesial temporal pathology that are also of prognostic importance given the differences in outcome between the two pathological groups. There was also evidence of a moderate to severe memory impairment in patients with AHS, and only mild memory deficits in those with isolated AS.The presence of mesial temporal (or "hippocampal") sclerosis in the surgically resected lobe is associated with a reduced incidence of postoperative seizures.23 The relation of AS to seizure outcome after temporal lobectomy has not been explored. Clinical observation (by LAM and RSM), however, has suggested that patients with AS have poorer postoperative seizure control than patients with AHS.Furthermore, the role of the hippocampus in memory function is now well established. Given that patients in the AS group underwent temporal lobe removals that included seemingly normal hippocampal tissue, postoperative decreases in memory for patients in this group might be expected. If indeed outcome for seizure control or memory function differs for these patients, then it becomes important to identify preoperative measures that are sensitive to the extent of mesial temporal pathology because, in the future, these measures could help to determine prognosis. Therefore, as well as outcome, several possible preoperative indicators were used to compare patients with AS and those with AHS. Methods SUBJECTSA consecutive series of 113 patients (age ) 13 years) who had a temporal lobectomy carried out at University Hospital for the relief of intractable seizures between January 1989 and December 1991 were considered for the present study. Surgery was carried out when (a) a focal seizure onset was shown, (b) the risks of surgery were low, and (c) the patient was psychologically prepared for surgery. Patients...

Diagnosis of DNT with imaging modalities alone may be difficult, but these radiologic features may aid in differentiating DNT from other gliomas.