Non-Invasive Skin Imaging of Pseudoxanthoma Elasticum Using Dynamic Optical Coherence Tomography: Insights from a Case-Control Study

Introduction: Pseudoxanthoma elasticum (PXE) is a rare genetic disorder characterized by progressive mineralization and fragmentation of elastic fibers, leading to multisystem involvement. Diagnosis relies on clinical features, histopathology, and, in selected cases, genetic testing, with cutaneous manifestations often representing the earliest signs. Objective: To validate dynamic optical coherence tomography (D-OCT) as a noninvasive diagnostic method for detecting PXE-related dermal abnormalities. Methods: In this case-control study, PXE patients evaluated at Umberto I Policlinic (Rome, Italy) between May 2023 and September 2024 underwent clinical and instrumental assessment. The left lateral cervical, retrocervical, left axillary, and periumbilical folds were analyzed using a standardized 0–3 clinical severity scale and D-OCT imaging. Control subjects were individuals undergoing routine mole checks. D-OCT quantified fiber density, attenuation, and vessel density at 300 µm and 500 µm depths. Statistical analysis included Spearman’s correlation and the Mann-Whitney U test, with p < 0.05 considered significant. Results: Twenty-three PXE patients and eleven controls were included. Cutaneous involvement was observed in 91.30% of patients, predominantly in retrocervical (86.95%) and lateral cervical (82.60%) areas. Clinical severity significantly correlated with D-OCT fiber density in the retrocervical region (ρ = 0.507). Compared with controls, PXE patients showed reduced fiber density and increased attenuation across most regions, except the axillae. At 500 µm depth, vessel density was markedly decreased in the axillary area, with approximately 2.5-fold fewer vessels in PXE skin. Conclusion: D-OCT effectively detects dermal alterations in PXE, including subclinical changes, providing a promising noninvasive alternative to skin biopsy.