Arias-stella atypia in a paratubal cyst - A rare phenomenon with potentialdiagnostic pitfalls

BACKGROUND: Arias-Stella reaction is commonly encountered in the endometriu m during the gestational period and puerperium. Similar changes in the tuba l epithelium ave exceedingly rave. The cytologic findings of this phenomeno n have never been described before. CASE: Cytologic findings of Arias-Stella changes in the lining cells of a l eft paratubal cyst in a 41-year-old woman were examined. The smears showed occasional small clusters or isolated tubal epithelial cells consisting of a mixture of ciliated and secretory cells. Some of the ciliated cells showe d a marked increase in nuclear and cytoplasmic volume and possessed coarse chromatin, prominent, angulated nucleoli, dense amphophilic cytoplasm; and a discrete cell membrane. The nuclear membrane was still thin and regular; and these cells were mitotically inactive. The preservation of apical cilia in some of them ensured thier benign nature, In some areas, clusters of se cretory cells with an increase in both nuclear and cytoplasmic volume and a mple, clear cytoplasm were also found. There were small, monolayered sheets of vEgulnl and benign-looking epithelial cells with a honeycomb al arrange ment, suggesting that the Arias-Stella atypia was focal. CONCLUSION: In view of the presence of scattered giant cells with coarse ch romatin and nngtrlnfpn macronucleoli, nfalse positive cytologic diagnosis o f malignancy can be made if one does not pay attention to the coexistence o f apical cilia and other subtle changes, including the usual nuclear/cytopl asmic I ratio, thin and regular membrane nuclear membrane and absence of mi totic activity.