Expanding the clinicopathological spectrum of late cutaneous Lyme borreliosis (acrodermatitis chronica atrophicans [ACA]): A prospective study of 20 culture-and/or polymerase chain reaction (PCR)-documented cases

Background: The diagnosis of acrodermatitis chronica atrophicans (ACA), the late cutaneous manifestation of Lyme borreliosis, can be challenging. Histologic changes in ACA have been described in a few studies from endemic countries, relying on cases documented by serology only. Objectives: We sought to reassess the clinicopathological spectrum of ACA in a series of thoroughly documented cases. Methods: Patients prospectively included in a national prospective study were selected on the basis of positive culture and/or polymerase chain reaction of a skin biopsy sample. The diagnosis of ACA was confirmed by reviewing the clinical and serologic data. Histopathological samples were carefully reviewed. Results: Twenty patients were included. Unusual clinical features (ie, numerous small violaceous patches and equidistant small spinous papules with background faint erythema) were observed in 2 patients. Histopathological examination revealed a classic plasma cellerich perivascular and interstitial pattern with telangiectases in 16 of 25 samples, whereas strikingly prominent granuloma annulareelike or lichenoid features were observed in 4 and 2 of 25 cases, respectively, and discrete nonspecific minor changes in 3 of 25 cases. Limitations: The small number of patients was a limitation. Conclusions: Genuine culture-and/or polymerase chain reactioneproven ACA can rarely present as numerous violaceous patches or cluster of spinous papules clinically, and as a granuloma annulareelike or lichenoid dermatosis histologically.