A reappraisal of the histopathologic criteria for the diagnosis of cutaneous allogeneic acute graft-vs-host disease

To determine the validity of the Lerner grading system and review the histo pathologic findings of cutaneous acute graft-vs-host disease (aGVHD), 78 sk in biopsy specimens from 49 bone marrow transplant recipients were evaluate d Histopathologic sections were independently reviewed twice by 3 pathologi sts and classified (Lerner system), without knowledge of the patients' clin ical evolution. Intraobserver agreement in grading aGVHD was substantial to almost perfect. Interobserver agreement between pairs of observers was mod erate to substantial on first review and substantial on second review. Over all, we found an almost perfect agreement in diagnosing Lerner grade III, w hereas areas of disagreement occurred with Lerner grades 0, I, and II. Hist opathologically specimens of patients who developed aGVHD (aGVHD-positive) showed significantly higher frequency of epidermal atrophy, spongiosis, dif fuse basal vacuolization, more than 3 single necrotic keratinocytes per hig h-power field, satellitosis, inflammatory infiltrate, with a predominantly lichenoid pattern, lymphocytic exocytosis, and dermal melanophages. When co nsidering skin samples classified as grade I and II, we found statistically significant differences between aCVHD-positive and aGVHD-negative cases on ly for the presence of inflammatory infiltrate, lymphocytic exocytosis, and satellitosis. Lerner grading is reproducible, although lesser agreement oc curred when evaluating grades I and II, and the Lerner grading system shoul d be revised by including the estimate of the inflammatory infiltrate as an additional criterion for grade II.