Cystadenoma of apocrine origin is a tumour of the sweat gland that is benign in nature.
Classification of this pathology is based upon histological characteristics plus histochemical analysis.
Prevalence of cystadenoma has been suggested to be quite rare, in the region of 1 in 1000 of subcutaneous biopsies observed.
Previous classification of cystadenoma via histological and immunohistochemical method; has revealed only two distinct entities and the term hydrocystoma was often used in place of cystadenoma.
More recent studies have suggested that a third type can be identified via immunohistochemical analysis.