Balloon cell naevus: new perspectives using high-definition optical coherence tomography with dermoscopic and reflectance confocal microscopic correlation

Balloon cell naevus (BCN) is considered a rare histopathological curiosity with no clinical features that allow a clear differentiation from other melanocytic naevi. Its name derives from the appearance of large, multinucleated cells arranged in lobules of varying size in the dermis. These cells display a small, round, central nucleus and their cytoplasm is often pale and vacuolated with small melanin granules.1 Recently, in vivo diagnostic techniques such as dermoscopy and reflectance confocal microscopy (RCM) offered new morphological details in BCN.2-4 They showed an excellent correlation with the histological presentation first described by Judalewitsch in 1901.5 Herein, we add some novel cytomorphological details using a new diagnostic tool, named high definition optical coherence tomography (HD‐OCT).