Report of Participants’
Meeting held on Thursday 5th July 2007
during the ‘Glasgow Pathology 2007’ meeting of the Pathological
Society and the BDIAP.
To cover cases in circulations X and Y
The meeting opened at 12.30 pm.
Professor Furness briefly outlined the results of the electron microscopy questionnaire which had been circulated to all EQA scheme participants on behalf of Professor Cook.
The results are available here in an Excel spreadsheet and summarised in a PowerPoint file.
In brief:
· The proportion of native renal biopsies in which EM is used is highly variable, but most laboratories use EM in a large majority of cases. This does not apply to renal transplant biopsies.
· Over one third of respondents rely on sending tissue samples to other laboratories to obtain EM.
· The majority of cases are studied by a trained BMS taking photographs and passing those photographs to the renal pathologist. A small proportion are examined by the renal pathologist examining the grids directly.
· Most pathologists envisage that in the future BMS will continue to produce images for the pathologist, but many would prefer to have time to examine the grids themselves. Some envisage more direct interpretation and reporting by BMS staff, either to the pathologist or (in the case of only 3 respondents) direct to the nephrologist.
· One quarter of respondents consider their EM facility to be ‘not stable’, due to a combination of impending senior staff retirement, ageing equipment and/or financial stringency. Some units using conventional photographic prints are conscious that their supply is limited and production of conventional photographic media has ceased, and they do not have resources to convert to digital imaging.
There was a brief discussion around the likely closure of many EM units, with remaining units doing more work to provide EM services to distant sites. The generation of digital images is likely to facilitate this, but there is a danger of fragmentation of the service. Training of a new generation of biomedical scientists to do this work needs to be addressed.
All participants had identified this as a case of membranous glomerulonephritis.
It was agreed that either minimal change nephropathy or primary focal segmental glomerulosclerosis should be regarded as correct. The electron microscopy showed some condensations of intracytoplasmic filaments in the podocytes, but these were not extracellular electron dense deposits of immune complex type; these had led to several suggested diagnoses of membranous glomerulonephritis, which was regarded as incorrect. ‘FSGS with early membranous’ was regarded as two separate diagnoses on one line, therefore justifying only half marks. The other proffered diagnoses were regarded by the meeting as incorrect.
The consensus diagnosis was IgA nephropathy.
On this occasion, the meeting decided that a diagnosis of Henoch Schonlein Purpura should be given only half marks, as there was nothing to suggest that clinically this would be regarded as HSP rather than IgA nephropathy. ‘IgA nephropathy and ANCA-associated disease’ was regarded as two separate diagnoses on one line, therefore justifying only half marks. The meeting specifically decided that given the material supplied, ‘Proliferative Gn ?IgA ?SLE ?postinfective’ was too indecisive and deserved no marks.
This was linear dense deposit disease (MCGn type II).
The meeting decided that ‘Dense membrane disease’ was an incorrect term and therefore should be given half marks, even if the respondent had actually meant dense deposit disease. The other proffered diagnoses were incorrect.
This was a case of myeloma cast nephropathy. The other proffered diagnosis was regarded as incorrect (especially as the information provided included the correct diagnosis!)
The consensus diagnosis was membranous glomerulonephritis. It was pointed out that in the information provided, the words ‘immunopositivity for … …light chains’ had caused some confusion, including the diagnosis of light chain nephropathy. It was agreed that this diagnosis could be excluded on the basis of examining the material available, so it should be regarded as incorrect. The other minority diagnoses were also regarded as incorrect. It was agreed that the case was suitable for scoring despite the numerous complaints about the absence of electron microscopy.
Professor Furness prefaced the discussion by acknowledging that several of the cases in this circulation had caused complaints about the inadequacy of the material circulated. Participants were reminded that in the future the identity of the contributor of each case would be published, specifically in an attempt to discourage the submission of such inadequate material.
Evaluation of this case was inhibited by having only a H&E section, and by the words in the information provided ‘IF showed small amount of IgA within paramesangium. Small amount of IgG in a peripheral location’. It was agreed that with no explanation of how to interpret the words ‘small amount’, it was impossible to know whether this was a pauci-immune process or an immune complex mediated glomerulonephritis.
The meeting discussed whether this case could be used for personal scoring or not. It was agreed that ‘granulomatous interstitial nephritis’ was wrong, but that if all other proffered diagnoses were merged to ‘Crescentic glomerulonephritis ?pauci-immune or not’, then the case could be retained.
The consensus diagnosis was lupus nephritis. It has previously been agreed that whenever participants make a diagnosis of SLE, they should also apply the ISN/RPS classification. The most popular class proffered was class III, at only 5.3/10. However, this case had been circulated with only a H&E section and a very brief description of the immunofluorescence. The ISN/RPS classification specifies a basement membrane stain as an aid to classification. Consequently, rather than discard the case for personal scoring, it was agreed that all diagnoses which mention SLE would be merged and regarded as correct. Responses which did not mention SLE were regarded as incorrect.
The consensus diagnosis, and that of the submitting pathologist, was of acute tubular injury or acute tubular necrosis. However, only a H&E section was circulated, and many participants had complained that this was too pale to be interpretable. Some participants complained that their section had no glomeruli. A record number of participants had indicated that this material was inadequate for use as an EQA case. As a result this case will not be used for personal scoring.
The clinical information provided strongly suggested a diagnosis of anti-GBM nephropathy / Goodpasture’s disease. The single H&E section circulated was relatively normal for that diagnosis, but did include at least one glomerulus with a cellular crescent. Anti-GBM nephropathy was regarded as the correct diagnosis. The other proffered diagnoses were regarded as incorrect.
The consensus diagnosis was of primary FSGS. There was some discussion as to whether specific sub-categories of FSGS should be regarded as correct, since the meeting did not feel that the characteristic features of collapsing glomerulopathy were present, nor were convincing tip lesions present, whereas segmental scars were present. However, after some discussion it was decided to merge all subclasses into ‘Primary FSGS’ rather than to penalise incorrect sub-classification.
All other diagnoses were regarded as incorrect. Specifically, the meeting agreed that this was not minimal change nephropathy and that diagnoses of proliferative glomerulonephritis were incorrect.
This case for education and interest will not be used for personal scoring. It was agreed that it represented the rare variant of monoclonal immunoglobulin deposition disease, ‘light and heavy chain nephropathy’. Consequently, a diagnosis of ‘light chain nephropathy’ was technically incorrect, even though it correctly identified the nature of the process, because heavy chain deposition was also occurring.
The meeting discussed possible future developments and improvements in the scheme. No changes were proposed.
It was agreed that the scheme should not at present move to using virtual slides rather than circulating glass slides. However, it was noted that virtual slides are a useful resource for teaching, and a reminder of the appearance of the glass slides. Several past circulations of the scheme are now available as virtual slides on the Leeds server at http://www.virtualpathology.leeds.ac.uk/eqa/index.php .
The meeting discussed the possibility of EQA scheme participation being part of the new medical specialist recertification process. While not particularly welcome, it was agreed that this would be preferable to proficiency testing proposals which would involve histopathologists re-sitting the MRCPath examinations every 5 years. It was agreed that such a move would make CPA accreditation more desirable, perhaps compulsory. Reports of moves to simplify the process of accreditation of interpretive EQA schemes with CPA were welcomed.
The meeting closed at 1.45 pm.