Diagnosing of primary cutaneous amyloidosis using dermoscopy and reflectance confocal microscopy

Background: Primary cutaneous amyloidosis (PCA) is apruritic and potentially disfiguring disorder; this disease is usually diagnosed clinically due to its common occurrence. However, for cases with atypical presentations or for those physicians not familiar with PCA, the diagnosis can be a challenge.

Objective: To observe the characteristics of PCA under dermoscopy and reflectance confocal microscopy (RCM) in order to gain experience and reference for clinicians to facilitate diagnosis.

Methods: The typical lesions of 110 patients with primary cutaneous amyloidosis were observed by dermoscopy and RCM, and scanning results were recorded. Thirty patients followed by complete excision for histopathological analysis.

Results: A total of 110 patients with clinically diagnosed PCA were enrolled. Forty-seven patients had lesions consistent with macular amyloidosis and 63 with lichen amyloidosus. The dermoscopic findings of PCA shared a common feature, each 'macule' was composed of a central hub pattern surrounded by brownish pigmentation, The pattern of the central hub could be brown, white, scar-like and structureless area. RCM features of total patients consisted of dermal papilla present cloud-like agglomerate which are high refractive index.

Conclusions: Dermoscopy and reflectance confocal microscopy can be used in the diagnosis of PCA, which can provide a basis for doctors to diagnose.