Sources of error in neuropathology intraoperative diagnosis.

OBJECTIVE: The goal of this study was to optimize intraoperative neuropathology consultations by studying trends and sources of diagnostic error. We hypothesized that errors in intraoperative diagnoses would have sampling, technical, and interpretive sources. The study also audited diagnostic strengths, weaknesses and trends associated with increasing experience. We hypothesized that errors would decline and that the accuracy of "qualified" diagnoses would improve with experience. METHODS: The pathologist's first 100 cases (P1), second 100 (P2), and most recent 100 (P3, after ten years in practice) formed the data set. Intraoperative diagnoses were scored as correct, minor error or major error using the final diagnosis as the gold-standard. Incorrect diagnoses were re-examined by two reviewers to identify sources of error. RESULTS: Among the 300 cases there were 22 errors with 11 in P1, 9 in P2 and 2 in P3. Sampling contributed to 17 errors (77%), technical factors to 7 (32%) and interpretive factors to 16 (73%). Improvement in diagnostic accuracy between P1 and P2 (p = 0.8143), or P2 and P3 (p = 0.0582) did not reach significance. However, significant improvement was found between P1 and P3 (p = 0.0184). CONCLUSION: The present study was a practical and informative audit for the pathologist and trainees. It reaffirmed the accuracy of intraoperative neuropathology diagnoses and informed our understanding of sources of error. Most errors were due to a combination of sampling, technical and interpretive factors. A significant improvement in diagnostic proficiency was observed with increasing experience.

A 22-year-old Australian woman with atypical subacute sclerosing panencephalitis diagnosed at postmortem.

Measles remains a significant global health problem. Despite the decline in measles prevalence in Australia following the implementation of a national vaccination program, challenges surrounding this disease remain. This report describes a 22-year-old woman who presented with coordination loss, tremor, choreiform movements and marked visual blurring, and her condition rapidly deteriorated to coma and death. Antemortem investigations did not yield a unifying diagnosis. Postmortem examination provided a diagnosis of subacute sclerosing panencephalitis. This patient had a rare neurological complication of measles infection, and her condition is remarkable for the atypical clinical presentation.

Percutaneous muscle biopsies: review of 900 consecutive cases at London Health Sciences Centre.

OBJECTIVE: In the present study we review our experience with 900 consecutive percutaneous muscle biopsies over the period 1993 to 2007. We examined the advantages and limitations of the procedure, biopsy site preferences, diagnostic range, frequency of diagnoses and quality of histopathology. Demographics, referral patterns and patients' perceptions of the procedure were also assessed. METHODS: Cases were identified through the London Health Sciences Centre Department of Pathology database. Standard biopsy procedures were followed using a manual trocar style instrument. With a neuropathology technologist in attendance at all biopsies, biopsies were oriented in the fresh state and snap frozen. RESULTS: Most referrals for muscle biopsy were from neuromuscular neurologists. The procedure was found to be efficient, well-tolerated and produced high quality specimens in all diagnostic categories. No major complications occurred. Failure to obtain an adequate tissue sample, although uncommon (< 2%), was usually due to marked obesity, edema or muscle wasting. Bleeding at the site was rarely problematic and no wound infections were reported. CONCLUSIONS: Needle muscle biopsies represent an efficient alternative to open biopsies when peripheral nerve sampling is not required and when large tissue samples are not needed for extensive biochemical analyses.