This paper describes our recent experience with one case of collagenous spherulosis of the breast which was diagnosed accurately by fine-needle aspiration (FNA) cytology. Histochemical and immunohistochemical studies were performed on the biopsy material. This curious lesion was found in association with benign proliferative breast processes but it can be found in association with both benign and malignant lesions in other organs and breast malignancies. The differential diagnosis of collagenous spherulosis is discussed.