Table 2:

Changes associated with reactive and benign pathologies in peritoneal washings.

Pathology	Cytologic finding	Pitfall
Inflammatory conditions	Mixture of mesothelial patterns in the same sample	Can be confused with cancer
Bulky benign tumors: • Leiomyomas • Ovarian fibrothecomas	Mixture of mesothelial patterns in the same sample	Can be confused with cancer
Adhesions	Capillary tangles
Detached ciliary tufts	Anucleated cytoplasmic fragments with cilia
Surface reactions • Endosalpingiosis • Endometriosis • Collagen globules (Collagen balls) • Surface component of benign tumors	Epithelial cell clusters with psammoma bodies Endometrial epithelial cells and stroma; hemosiderin-laden macrophages Small round bodies of collagenized stroma and flat mesothelial cells Epithelial cells forming cast-like group of ovarian surface clefts	Pattern overlaps with serous tumors of low malignant potential and carcinoma Can be confused with cancer Overlaps with low-grade carcinomas
Ruptured benign epithelial cyst or cystic tumor	Sheets and groups of epithelial cells	Can be confused with carcinoma