Erythema elevatum diutinum - a chronic leukocytoclastic vasculitis microscopically indistinguishable from granuloma faciale?

Background: As the sequential inflammatory changes are the same in erythema elevatum diutinum (EED) and granuloma faciale (GF), histopathologic distinction may be difficult.

Methods: All available cases from 1998 to 2009 with the diagnosis of EED and GF were collected and reviewed, both clinically and histopathologically. Nine cases of EED and 41 cases of GF were reviewed in a blinded fashion using a checklist of 26 histopathologic criteria.

Results: Only four of the evaluated criteria showed differences between GF and EED. High density of the infiltrate was noted in 97% of cases of GF but only in 56% of cases of EED. Eosinophils were the predominant cell type in 59% of cases of GF but in none of the cases of EED. Plasma cells were more frequent in GF (64%) than in EED (22%), and granulomas were never found in GF but in 22% of EED. A zone of perijunctional sparing (Grenz zone) was observed in about three quarters of the cases in both the groups.

Conclusions: The histopathology of GF and EED is very similar and overlapping. The presence of a Grenz zone and patterned fibrosis does not distinguish the two diseases. However, granulomatous nodules are only seen in EED, and a predominance of eosinophils in the infiltrate favors a diagnosis of GF.