balloon cell nevus balloon cell nevus balloon cell nevus is a benign nevus. it appears like a melanocytic nevus. balloon cell nevusspecialtydermatology histologically it is characterized by swollen, pale, polyhedral melanocytes, with pale cytoplasm and a central nucleus. it is different to balloon cell melanoma, which has larger nuclei and is structured like a melanoma. it was first described by judalaewitsch in 1901.