Reflectance confocal microscopy may consistently, accurately diagnose melanoma

Key takeaways:

• Certain melanomas consistently had two dermoscopic patterns, whereas others had three.
• Regardless of varying patterns, reflectance confocal microscopy accurately diagnosed all melanoma cases.

Reflectance confocal microscopy may increase consistent and accurate melanoma diagnoses independently of clinical and dermoscopic features, according to a study.

“Reflectance confocal microscopy (RCM) is a noninvasive, in vivo tool that provides an optical biopsy through horizontal skin scanning at nearly histologic resolution,” Cristina Faldetta, MD, of the dermatology clinic at University of Modena and Reggio Emilia in Modena, Italy, and colleagues wrote. “RCM has been estimated to further reduce the number of unnecessary biopsies by 43.4% compared to dermoscopy alone.”

To describe and compare dermoscopic and RCM features of cutaneous melanomas with histopathological confirmation, the authors conducted a single-center, retrospective analysis of consecutive melanomas evaluated with RCM from 2015 to 2019.

Of 583 melanoma cases (56.1% men; mean age, 57.9 years), 40.1% were typical lesions, 35.7% were nevus-like, 9.4% were amelanotic/non-melanocytic skin cancer (NMSC)-like, 3.3% were seborrheic keratoses (SK)-like, and 11.5% were lentigo maligna-like.

The most common dermoscopic features across all melanocytic lesions were atypical network (83%) and regression structures including white scar-like pigmentation and/or blue pepper-like granules (63.2%).

More than 50% of nevus-like lesions, SK-like lesions and lentigo/lentigo maligna-like lesions consistently displayed two patterns: atypical network plus regression structures and nonevident follicles plus heavy pigmentation intensity.

On the other hand, more than 50% of amelanotic/NMSC-like lesions consistently displayed three patterns: atypical network, atypical vascular pattern and regression structures.

Since almost all lesions were consistent with melanoma diagnosis, these varying features were less evident with RCM and confirmed as melanoma.

“Our analysis underlines that this spectrum of melanoma presentation persists with dermoscopy, with differential diagnoses of nevus-like, amelanotic/NMSC-like and SK-like lesions by dermoscopy alone being especially difficult,” the authors concluded. “Conversely, few differences between clusters were observed with RCM evaluation, and thus RCM has the potential to augment our ability to consistently and accurately diagnose melanoma independently of clinical and dermoscopic features.”