We report the case of a spiradenocarcinoma (malignant eccrine spiradenoma), a rare variant of a malignant sweat gland tumor, which occurred in the scalp of a 63-year-old woman. Some years before the current tumor occurred, a tumour of unknown histology had been excised from the same localization. The new tumor presented with rapid growth and exulceration. Malignant eccrine spiradenoma is characterized by the coincidence of a benign and a malignant portion within one specimen. We report case example 47 of this entity. The peculiarity of this case is the enormous heterogeneity with foci of atypical histiocytes like an atypical fibroxanthoma and an extensive foreign body reaction with cholesterol needles as in a xanthogranuloma. Static DNA cytophotometric analysis revealed different degrees of aneuploidy in the three tumor portions. The follow-up of 23 months is without recurrent tumor. A review of the literature is given.