Clinical and Histopathologic Study of Confluent and Reticulated Papillomatosis by Anatomic Site and Age.

Background: Confluent and reticulated papillomatosis (CRP) is an uncommon dermatosis characterized by hyperpigmented scaly macules or papillomatous papules coalescing into confluent patches or plaques centrally with a reticular pattern peripherally. Few studies regarding this have been reported in the literature.

Objective: The purpose of this study was to investigate the clinical and histologic characteristics of CRP in Korean patients according to anatomic site and age.

Methods: We retrospectively reviewed the medical records, clinical photographs, and 40 histopathologic slides of 29 patients diagnosed with CRP.

Results: Sixteen adults and 13 adolescents were included. The predominantly involved anatomic sites were the trunk (89.7%) and axillae (27.6%); flexural area involvement was mainly found in the adolescent group. The mean disease duration was 2.3 times longer in the adult group than in the adolescent group. The histopathologic features included hyperkeratosis (95.0%), acanthosis (87.5%), and papillomatosis (77.5%) in the epidermis. In the adult group, only 10 specimens (52.6%) showed mild to moderate papillomatosis. There was no relationship between the histologic findings and disease duration; however, the former was associated with the anatomic site.

Conclusion: The present study is the first to present the clinical and histologic features of CRP according to age and anatomic site in Korean patients. The patients in this study more frequently had fungal infections (31%) than patients in a previous study (12.8%). Histologic changes were more prominent in the adolescent group than in the adult group and in the flexural area than in the non-flexural area.