Fine needle aspiration cytology of malignant spiradenoma arising in congenital eccrine spiradenoma.

The fine needle aspiration (FNA) cytology of malignant eccrine spiradenoma arising in a large benign congenital eccrine spiradenoma is described. The malignant tumor was characterized by cohesive, pleomorphic cells with malignant nuclear features and numerous mitoses. FNA of the adjacent benign eccrine spiradenoma revealed prominent basement membrane deposition with an irregular tubular and nesting growth pattern and bland basaloid cells. To our knowledge, the FNA of malignant eccrine spiradenoma has not been previously described. In this case, FNA cytology was influential in directing patient management.