Actinic granuloma is a unique and distinct entity: a comparative study with granuloma annulare

Since the initial description of actinic granuloma (AG), debate has continued over whether it should be considered a specific condition or simply granuloma annulare (GA) located in sun-exposed areas of skin. We conducted a case-control study to clarify this issue. Twenty cases given the diagnosis of AG between 1991 and 2001 were retrieved from our archives. We applied the following inclusion criteria: extensive loss of elastic tissue in or at the side of the granuloma, and elastophagocytosis. Sixteen cases of GA that involved sun-exposed and non-sun-exposed sites, 8 cases from each group, were randomly selected as controls. Histologic parameters were quantitated on hematoxylin-eosin, Verhoeff van Gieson, and Alcian blue stains for each case. Results were statistically analyzed by SPSS program version 9. Fourteen cases of AG met our inclusion criteria. Presence of mucin, occurrence of multinucleated giant cells, and the type of granulomata were of high statistical significance (p < 0.01) in distinguishing the two entities. We also found that the location of the granulomata in these conditions is different and of statistical significance (p < 0.05). Based on histomorphology, we believe that AG should be considered a separate, independent condition and should be distinguished from GA even in sun-exposed areas of skin.