Fibroelastolytic papulosis: two cases of disease spectrum variants.

Fibroelastolytic papulosis (FEP) is an acquired cutaneous disorder of elastin that encompasses both white fibrous papulosis of the neck (WFPN) and pseudoxanthoma elasticum (PXE)-like papillary dermal elastolysis (PDE). Although FEP is a benign acquired disorder, it shares overlapping clinical features with pseudoxanthoma elasticum (PXE), a genetic disorder with systemic manifestations. We report two cases of FEP, including the WFPN and PXE-like PDE variants, in elderly women. In one case, a woman in her 70s with hyperlipidemia and chronic kidney disease presented with white-to-yellow, smooth, monomorphic papules coalescing into plaques on the posterior neck and bilateral antecubital fossa. A punch biopsy and elastic stain revealed a loss of elastic fibers in the papillary dermis. Based on these findings, we diagnosed our patient with PXE-like PDE. In another case, a woman in her 60s with no significant medical history similarly presented with skin-colored, smooth monomorphic papules on the posterior and anterior neck. A punch biopsy was also performed and an elastic stain showed a loss of elastic fibers in the papillary dermis, confirming the diagnosis of WFPN. Although rare, FEP is an important entity for dermatologists to recognize and differentiate from PXE given the potential for systemic complications in PXE.