Malignant eccrine spiradenoma is an extremely rare neoplasm of adnexal origin. It almost always originates from a preexisting long standing eccrine spiradenoma. We present a case of malignant eccrine spiradenoma arising from benign counterpart and having both carcinomatous and sarcomatous differentiation. Here we present a case of a 46 years old lady who presented with a long standing small nodule on her left leg of 7 years' duration with suddenly increase in size. Grossly the mass was partly solid and partly cystic measuring 11.5 cm in maximum dimension with cystic area forming the deeper plane. On microscopy, the superficial dermis showed well demarcated lobules of benign eccrine spiradenoma. Deeper dermis showed tumor cells with features of malignant transformation having both carcinomatous and sarcomatous component. After wide local excision patient is now doing well. The diagnosis of malignant eccrine spiradenoma requires a thorough histopathological examination of the lesion and requires finding a focus of benign spiradenoma within or adjacent to malignant tumour. Wide local excision and close follow-up for early detection of recurrence and metastasis is the mostly recommended management modality.