Cross-Polarized Macro Photography versus Polarized Dermoscopy in Basal Cell Carcinoma: A Blinded Paired-Image...

Polarized dermoscopy (PD) is the established non-contact imaging modality for basal cell carcinoma (BCC). Cross-polarized macro photography (CPMP) applies analogous optical principles using widely available equipment, but its performance relative to PD has not been systematically evaluated.

To compare dermoscopic feature visibility, image quality, and expert modality preference between CPMP and PD in BCC using a blinded, paired-image design.

One hundred paired CPMP and PD images of histopathologically confirmed BCCs, acquired during the same clinical visit, were digitally masked to remove modality-revealing cues and reviewed in randomized side-by-side pairs. Feature visibility was assessed by three dermoscopists; image quality by a multidisciplinary panel using the DIQS-5 (a structured 5-point dermoscopic image quality scale); and modality preference by three dermatologists with varying CPMP familiarity across two blinded rounds with a washout period.

Feature visibility did not differ significantly for any established BCC criterion (all P > 0.05). CPMP scored significantly higher for depth of field and color fidelity (both P < 0.001); sharpness was comparable between modalities (P = 0.494). CPMP captured all lesions ≥1 cm in a single frame, whereas 41.5% of large lesions exceeded PD's field of view. The majority of raters preferred CPMP in both evaluation rounds, with phenotype-dependent patterns: CPMP was favored for pigment-rich lesions and PD for lesions with fine vascular structures.

CPMP demonstrated feature visibility comparable to PD while offering measurable advantages in depth of field, field of view, and color rendering, suggesting complementary roles for these modalities in BCC imaging.