Related Experiment Video
Updated: May 11, 2026
Symmetric Bihemispheric Postmortem Brain Cutting to Study Healthy and Pathological Brain Conditions in Humans
Published on: December 18, 2016
Consensus recommendations on pathologic changes in the hippocampus: a postmortem multicenter inter-rater study
Tuomas Rauramaa1, Maria Pikkarainen, Elisabet Englund
1Department of Pathology, Kuopio University Hospital.
Insights
Neuropathologists established consensus on diagnosing hippocampal sclerosis (HS). The term HS should specifically denote neuronal loss and gliosis, excluding microinfarction, to improve diagnostic clarity.
Area of Science:
- Neuropathology
- Neuroscience
- Pathology
Background:
- The term "hippocampal sclerosis" (HS) lacks a standardized pathologic definition, leading to diagnostic ambiguity.
- Variability in HS diagnosis impacts research and clinical understanding of associated conditions.
Purpose of the Study:
- To evaluate inter-rater agreement among neuropathologists for diagnosing HS.
- To propose consensus recommendations for the consistent application of the term "HS" in neuropathologic diagnosis.
Main Methods:
- A panel of four neuropathologists assessed 251 autopsy cases with suspected HS.
- Cases were evaluated using hematoxylin and eosin-stained sections and descriptive definitions.
- Immunohistochemistry was utilized to identify neurodegenerative lesions.
Main Results:
- Initial diagnostic agreement for HS varied significantly (0%-86%), with higher agreement for vascular lesions (36%-70%).
- A joint review emphasized the necessity of immunohistochemistry for detecting neurodegenerative changes.
- Consensus defined HS as complete/near-complete neuronal loss and gliosis in the cornu Ammonis, excluding microinfarction.
Conclusions:
- The term "HS" should be reserved for cases exhibiting specific neurodegenerative patterns.
- Etiology of HS requires clarification as either neurodegenerative or "lacking neurodegenerative markers" (presumed hypoxic/ischemic).
- Standardized criteria will enhance diagnostic accuracy and consistency in neuropathology.
Abstract:
There is no consensus on the pathologic conditions or severity implied by the term "hippocampal sclerosis" (HS). In this study, a panel of experienced neuropathologists evaluated inter-rater agreement for pathologic diagnoses in the hippocampus and proposes consensus recommendations on the use of the term "HS." In a group of 251 cases of HS selected from a large autopsy cohort (1,388; 18%), a coordinating group identified 5 patterns of degenerative or vascular pathology. Four independent neuropathologists assessed a single set of hematoxylin and eosin-stained sections following descriptive definitions to classify the appearances and assign the diagnosis of HS, if appropriate. Diagnostic agreement (range, 36%-70%) was highest for vascular lesions. Subsequent joint review of all cases highlighted the need to identify neurodegenerative lesions using immunohistochemistry. Initial agreement in assigning the diagnosis of HS varied from 0% to 86%. After a joint review, the group recommended that the term "HS" should be applied to all cases with complete/near-complete neuronal loss and gliosis in the subfields of the cornu Ammonis but not to hippocampal microinfarction. Therefore, the etiology of HS must be defined in association with a neurodegenerative process or as "lacking neurodegenerative markers," a pathologic condition presumed to arise from hypoxic/ischemic mechanisms.
