Cytologic features of ovarian tumors of low malignant potential in peritoneal fluids

The distinction of ovarian tumors of low malignant potential (OTLMP) from invasive ovarian carcinomas has significant therapeutic and prognostic implications. This study was undertaken to define the cytologic features of OTLMP in peritoneal fluids and to compare them with the cytologic features of invasive carcinomas. Peritoneal fluids from 13 patients with OTLMP and 10 patients with invasive ovarian carcinoma contained neoplastic cells and were reviewed with attention to papillary fragment morphology, cellular pleomorphism and cytoplasmic and nuclear characteristics. Cytologic preparations from patients with OTLMP contained large, cohesive papillary fragments with smooth borders. The neoplastic cells were relatively small and uniform, with high nuclear-cytoplasmic (N/C) ratios (greater than 1:2), few intracytoplasmic vacuoles and inconspicuous nucleoli. Mitotic figures were rare. Peritoneal fluids from patients with invasive ovarian carcinoma contained smaller discohesive papillary fragments with irregular borders. The neoplastic cells were relatively large and pleomorphic, with low N/C ratios (less than or equal to 1:2), abundant intracytoplasmic vacuoles and prominent nucleoli; most preparations contained many single cells and mitotic figures.