We report a case of multiple benign nodular hidradenomas associated with malignant nodular hidradenoma in a hypogonadic patient.A 49 year-old man presented 11 benign nodular hidradenomas in the pectoral region. A malignant nodular hidradenoma had recently appeared in this region some distance from the pre-existing benign modular hidradenomas. This patient had peripheral hypogonadism associated with congenital bilateral cryptorchidia responsible for gynecomastia due to "relative hyperestrogenism". Large numbers of estrogen receptors were demonstrated in each of the benign nodular hidradenomas. The malignant nodular hidradenoma mass was unavailable and screening for these receptors was not possible.Cases of multiple nodular hidradenoma are extremely rare: we have seen only two. To the best of our knowledge, there have been no reports to date of combined malignant nodular hidradenoma and multiple benign nodular hidradenoma. However, there is histological evidence of transition forms. The coexistence of endocrine anomalies associated with this type of tumour has never been reported. However, the presence of estrogen receptors has occasionally been demonstrated in benign nodular hidradenomas. Our patient's endocrine disease may have played a role in the presentation of multiple hidradenomas, but this cannot be demonstrated.