A Histopathological Comparative Study between Erythema Multiforme and Acute Cutaneous Graft - versus - Host Reactions

Yoon, Tae Young

Abstract

BACKGROUND: The histopathological findings of acute cutaneous graft-versus-host reaction are similar to that of erythema multiforme.
OBJECTIVE
The objective of this study was to compare the histopathological findings of acute cutaneous graft-versus-host reactions with that of erythema multiforme.
METHODS
Histopathological setions of 9 patients with grade 2 acute cutaneous graft-versus- host. reactions and of 13 patient,, with erythema multiforme were reviewed.
RESULTS
Parakeratosis, the degree of the exocytosis and the endothelial cell swelling were not useful in the differential diagnosis between acute cutaneous graft-versus-host reactions and ery- thema multiforme. Rete ridge effacement and relative hyperkeratosis were characteristic in many cases of acute cutaneous graft-versus-host reactions but absent in erythema multiforme. Spongiosis, vacuolar degeneration of the basal cells, perivascular lymphocytic infiltration and erythrocyte extravasation were usually more prominent in erythema multiforme than in acute cutaneous graft-versus-host reactions. The number of dyskeratotic cells per epidermal linear mm was usually higher in erythema multiforme but not in acute cutaneous graft-versus-host reactions. An eosinophilic infiltrate was observed occasionally in erythema multiforme but not in acute cutaneous graft-versus-host reactions.
CONCLUSION
The histopathological findings show the same pattern of interface dermatitis and are different only in degree beween acute cutaneous graft-versus-host reactions and eryt,hema multiforrne. Rete ridge effacement and relative hyperkeratosis speaks for a diagnosis of acute cutaneous graft-versus-host reactions, and an eosinophilic infiltrate for a diagnosis of erythema multiforme.