Nodular hidradenoma may also be referred to as clear cell hidradenoma (when there is a prominent clear cell component) or eccrine acrospiroma. A lesion with numerous aliases, it has also been referred to as clear cell myoepithelioma, solid-cystic hidradenoma and eccrine sweat gland adenoma of clear cell type.
Nodular hidradenoma is a benign dermal-based skin appendageal neoplasm most commonly seen around axillary and scalp regions. There is no connection with the overlying epidermis.
Lesions display a nodular, lobulated, cystic and solid growth pattern and are composed of an admixture of both eosinophilic and clear cells. Trichilemmal-like keratinisation is common, and focal sebaceous differentiation may also be seen. When clear cells predominate, lesions may be referred to as clear cell hidradenoma.
Tumours usually behave in a benign fashion, but may rarely behave aggressively, and may recur if inadequately excised.
When exhibiting striking clear cell differentiation, the possibility of a metastatic clear cell tumour may need to be considered.