COLLAGENOUS SPHERULOSIS - REPORT OF A CASE WITH DIAGNOSIS BY FINE-NEEDLE ASPIRATION BIOPSY WITH IMMUNOCYTOCHEMICAL AND ULTRASTRUCTURAL OBSERVATIONS

Collagenous spherulosis (CS) is a benign breast lesion usually seen in association with other benign proliferative processes in the breast. To the best of our knowledge, this is the second fine needle aspiratio n (FNA) cytologic report of CS and the first with corresponding immuno cytochemical and ultrastructural studies performed on the subsequent b iopsy material. Cytologically, the aspirate consisted of scattered, me tachromatically staining hyaline globules seen best with Diff-Quik sta in in intimate association with numerous groups of benign ductal cells , some of which had a papillary configuration. The globules exhibited periodic acid-Schiff positivity. A subsequent excisional biopsy confir med the cytologic impression and revealed a multifocal process of duct al papillomas and papillomatosis containing numerous eosinophilic sphe rules with morphologic features and histochemical staining reactions t ypical of CS. Electron microscopic and immunoperoxidase studies sugges t the spherules to be composed predominantly of basement membrane prot eins, specifically type IV collagen, laminin and fibronectin, and to b e derived principally from myoepithelial cells. Although CS has been f ound primarily in benign breast lesions, it can be found in other orga ns and in association with both benign and malignant processes. The di fferential diagnosis of other breast lesions that can be confused with CS on FNA biopsy is presented.