Balloon cell change in cellular blue nevus

Balloon cells are altered melanocytes with clear vacuolated cytoplasm cause d by a defect in the process of melanogenesis. Although rare, balloon cell change has been observed in a variety of melanocytic proliferations, partic ularly intradermal melanocytic nevi and melanoma. When present, such featur es may lead to difficulties in diagnosis, particularly with other clear cel l neoplasms. We report an unusual case of the development of balloon cell c hange in a cellular blue nevus, a phenomenon that has not been extensively addressed in the literature. The importance of recognizing this change in c ellular blue nevus to avoid misinterpreting the lesion as malignant is disc ussed.