DigestivePathJC

@GIPathJC Since pathologists do not categorize dysplasia as conventional or non-conventional dysplasia, it is difficult to answer this question at this time.

@GIPathJC The majority of missed dysplastic lesions were non-conventional subtypes with hypermucinous dysplasia being the most common subtype.

@GIPathJC I don’t recall finding a case of “false positive” (i.e., completely normal colon was called as dysplasia or non-conventional dysplasia).

@GIPathJC In our experience, non-conventional dysplasia was often reported as indefinite for dysplasia or had a descriptive diagnosis (such as ‘glandular atypia,’ ‘crypt atypia’, ‘atypia,’ ‘favor reactive atypia,’ etc) without a definite diagnosis of dysplasia.

@GIPathJC However, in our analysis of 207 consecutive total colectomy or proctocolectomy specimens of IBD patients, we found a total of 49 missed dysplastic lesions in 27 patients (13%).

@GIPathJC So, I would say that “false negative” cases are not uncommon, as many non-conventional dysplasia cases were ignored or missed as negative for dysplasia.

@GIPathJC One more thing. Aberrant p53 expression was also noted in up to 50% of hypermucinous dysplasia. It can be useful in this setting as well.

@GIPathJC In addition, it is reported that SATB2 loss could be potentially useful in identifying IBD-associated dysplasia; however, in our experience, SATB2 is often patchy and weak (even in normal colon) and difficult to interpret, so we don’t recommend this stain at this time.

@GIPathJC We do not regularly perform p53 immunostaining in IBD-associated dysplasia cases.  A diagnosis of dysplasia should be based on morphologic findings.

@GIPathJC However, wild-type staining pattern does not exclude a diagnosis of dysplasia, and pathologists should not be deterred from making a diagnosis of dysplasia even if p53 is weak or patchy (wild-type)

@GIPathJC If p53 staining is weak or patchy in a potential crypt cell dysplasia case, we often use a descriptive diagnosis (e.g., “crypt cell atypia”) or a diagnosis of indefinite for dysplasia.

@GIPathJC However, in challenging situations like crypt cell dysplasia (mild enlargement and hyperchromasia of round/mildly irregular, non-stratified nuclei limited to the crypt base, no surface involvement), strong and diffuse p53 staining can be potentially helpful.