Two blue nodules on the right leg

Abstract

Hidradenoma is an asymptomatic, benign, sweat gland tumor with apocrine or eccrine differentiation. Most common dermoscopic features are bluish or pinkish homogenous areas, white structures, and vascular structures such as arborizing telangiectasias and polymorphous atypical vessels. Therefore, they mimic other malignant tumours such as basal cell carcinoma and melanoma. As this tumor is a great masquerader, one should keep in mind hidradenoma in the differential diagnosis, when the blue color is seen on dermoscopy. Due to the risk of hidradenocarcinoma development on a pre-existing hidradenoma, the management of this tumor is surgical excision.