Malignant nodular hidradenoma of the eyelid: a rare sweat gland tumor.

We report a case of malignant nodular hidradenoma in a middle-aged man, who presented with a nodular swelling in the eyelid. The tumor was similar to its benign counterpart but had additional features such as surface ulceration, numerous mitiotic figures, and an infiltrative growth pattern. Malignant forms of hidradenomas are unusual and the possibility this variant should be considered in the differential diagnosis of eyelid tumors.