Liesegang rings in a needle aspirate from a breast cyst.

Ringlike structures of various sizes, resembling Liesegang rings (LRs), were found in the needle aspirate from a breast cyst in an elderly woman. They were characterized by a double-layer outer wall with striations and an amorphous central nidus. Immunohistochemical stains for calcium, iron, mucus, glycogen, amyloid, cytokeratin and epithelial membrane antigen yielded negative results. Since LRs can be mistaken for ova, larvae or parasites, it is important that cytologists be aware of their occurrence, albeit infrequent, in aspirated material to avoid a misdiagnosis.