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Dementia lacking distinctive histopathology: clinicopathological evaluation of 32 cases
P Giannakopoulos1, P R Hof, C Bouras
1Geriatric Hospital, University of Geneva School of Medicine, Switzerland.
Abstract:
We report the neuropathological findings in 32 patients, aged 46-86 years, with dementia lacking distinctive histopathology. All of the patients were classified clinically as having Pick's or atypical Pick's disease, but the routine neuropathological evaluation showed no specific histopathological changes such as Pick bodies, senile plaques, neurofibrillary tangles or Lewy bodies. In 50% of the cases the first symptoms appeared before 65 years of age. However, there were 9 patients with onset in the eighth decade. Positive family history was found only in 6 presenile cases. The retrospective evaluation of the clinical records revealed the consistent presence of "frontal" symptomatology, including loss of personal awareness, inappropriate euphoria and stereotyped behavior. Speech disorders were observed in 80% of the cases, whereas temporospatial disorientation and memory impairment were less frequent. Praxis and gnosis were strikingly preserved in most of the cases. The macroscopic neuropathological examination revealed frontal or temporopolar atrophy in 97% of the cases, while the hippocampus and subcortical structures were relatively spared in the majority of the cases. Histologically, four groups were recognized. Group A showed moderate to severe neuron loss and gliosis in the frontal and/or temporopolar cortex without subcortical involvement. In group B, the neocortical cell loss was widespread, and the striatum and substantia nigra displayed differential degrees of gliosis but no neuron loss. Group C patients showed a lesion distribution comparable to that observed in group B but with severe neuron loss in at least one subcortical region. Four cases formed group D, which was characterized by the preservation of the pyramidal neurons in the neocortex and variable subcortical changes. Despite these differences in the topography of pathological changes, all of the cases shared a similar clinical profile. These findings further demonstrate the epidemiological and neuropathological heterogeneity of dementia lacking distinctive histopathology. Furthermore, they suggest that the same clinical manifestations may correspond to several distinct pathological processes in this condition.
Insights
Dementia lacking distinctive histopathology presents diverse neuropathological findings despite similar clinical profiles. This study highlights the heterogeneity of this dementia type, suggesting varied underlying pathological processes.
Area of Science:
- Neuropathology
- Neuroscience
- Geriatrics
Background:
- Dementia lacking distinctive histopathology (DLDP) is clinically diagnosed when routine neuropathological evaluation reveals no specific changes.
- Pick's disease and atypical Pick's disease are clinical classifications sometimes used for DLDP, but lack characteristic histopathological markers like Pick bodies or Lewy bodies.
Purpose of the Study:
- To investigate the neuropathological heterogeneity of dementia lacking distinctive histopathology.
- To correlate clinical and pathological findings in a cohort of patients with DLDP.
Main Methods:
- Retrospective analysis of clinical records and neuropathological findings in 32 patients diagnosed with DLDP.
- Macroscopic examination for brain atrophy and histological assessment of neuronal loss and gliosis in cortical and subcortical regions.
- Classification of cases into four neuropathological groups based on lesion distribution.
Main Results:
- Consistent "frontal" symptomatology (e.g., loss of personal awareness, euphoria) was observed in 97% of cases with frontal or temporopolar atrophy.
- Speech disorders were common (80%), while memory impairment and disorientation were less frequent. Praxis and gnosis were preserved.
- Four distinct neuropathological groups (A-D) were identified based on the distribution of neuronal loss and gliosis, with varying involvement of neocortical and subcortical structures.
Conclusions:
- Dementia lacking distinctive histopathology exhibits significant neuropathological heterogeneity.
- The same clinical presentation can arise from diverse underlying pathological processes, underscoring the complexity of DLDP.
- Further research is needed to elucidate the specific mechanisms driving these distinct pathological subtypes.