Dermoscopy Combined With Reflectance Confocal Microscopy Improves Diagnostic Accuracy of AHLM/LMMs

ATRPhoto/Adobe Stock

In a recent study spanning a decade, researchers delved into the diagnostic landscape of amelanotic/hypomelanotic lentigo maligna/lentigo maligna melanoma (AHLM/LMM), shedding light on the efficacy of combining dermoscopy and reflectance confocal microscopy (RCM).

The study, published in The Journal of Dermatology, was conducted across 5 participating centers between January 2010 and December 2019. Researchers examined consecutive cases of histopathologically confirmed lesions, including AHLM/LMMs, amelanotic/hypomelanotic basal cell carcinoma and squamous cell carcinoma (AHBCCs/AHSCCs), amelanotic/hypomelanotic benign lesions (AHBLs), and actinic keratosis (AKs).

Dermoscopic and RCM images from 224 lesions in 216 patients were evaluated by a panel of 3 blinded observers. Diagnostic performances, including sensitivity, specificity, accuracy, predictive values, and level of confidence, were calculated for each diagnostic procedure. The study aimed to examine the utility of combining dermoscopy and RCM in enhancing diagnostic accuracy for AHLM/LMMs.

The study's population consisted of 55 AHLM/LMMs, 62 AHBCC/AHSCCs, 56 AHBLs, and 51 AKs.

Both dermoscopy and RCM exhibited diagnostic performance exceeding 97% in distinguishing AHLM/LMMs from AHBCC/AHSCCs, with their combination further improving accuracy to 99.1%. The combination also demonstrated increased diagnostic confidence, raising high confidence levels from 36.2% to 76.6% in the diagnosis of AHLM/LMMs versus AHBLs.

The study emphasized the challenges in differentiating AHBCC from AHLM/LMM dermoscopically due to shared features. RCM, however, revealed distinct features facilitating easier discrimination. Dermoscopy plus RCM significantly increased confidence levels in diagnosing AHLM/LMMs compared to AHBLs and AKs.

The discussion also addressed the difficulty in distinguishing AHLM/LMM from AK using RCM, attributing it to confounding features like intraepidermal Langherans dendritic cells. The integration of dermoscopy with RCM was deemed crucial in improving diagnostic certainty, potentially reducing unnecessary biopsies or surgical excisions.

"This study shows that the integration of dermoscopy and RCM increases the level of diagnostic certainty in the diagnosis of AHLM/LMMs versus AHBCCs/AHSCCs, AHBLs, and AKs compared to dermoscopy and RCM alone," wrote study authors Pizzichetta et al. "This is particularly important for AHBLs and AKs because besides increasing the sensitivity in diagnosing AHLM/LMMs, the combination of the two techniques can reduce the number of dermoscopically equivocal lesions to address to biopsy or surgical excision to confirm the diagnosis. In conclusion, dermoscopy and RCM should be complementary to improve not only diagnostic accuracy, but also the level of diagnostic certainty in the diagnosis of AHLM/LMMs, a difficult-to-diagnose subtype of melanoma."

Reference

Pizzichetta MA, Polesel J, Perrot JL, et al. The combination of dermoscopy and reflectance confocal microscopy increases the diagnostic confidence of amelanotic/hypomelanotic lentigo maligna. J Dermatol. Published January 13, 2024. Accessed January 16, 2024. https://doi.org/10.1111/1346-8138.17075