The relationship between papillary infarction and microinvasion in ovarian atypical proliferative ("borderline") serous and seromucinous tumors.

Papillary infarction is commonly observed in ovarian atypical proliferative serous and seromucinous tumors (APST/APSMT), but there are no published data on its significance. This study characterizes the features associated with papillary infarcts and microinvasion to further understand these phenomena. From consecutive hospital-based cases, 32 APST/APSMT in 26 patients (6 bilateral) were reviewed and evaluated for papillary infarcts, microinvasion (<5 mm), and other histologic features. Among the tumors, 69% were APSTs and 31% APSMTs. Infarcts were identified in 46% of patients, and microinvasion in 27%. Microinvasion was significantly more common in tumors with infarcts (50%) than in those without (7%; P=0.0261). Papillary infarcts were significantly more common in APSTs (61%) than in APSMTs (13%; P=0.0357). The microinvasive tumors were significantly more likely to be bilateral (57% vs. 11%, P=0.0278). The mean infarct size in the presence of microinvasion was 5.9 mm, and in the absence of microinvasion, 2.2 mm (not significant). The infarcts were topographically separate from the foci of microinvasion. Other features evaluated showed no meaningful correlations with microinvasion or infarction. Proliferative noninvasive serous tumors with papillary infarcts are significantly more likely to have microinvasion, and papillary infarcts are more common in APSTs than in APSMTs. APSTs with microinvasion are more common than earlier appreciated. Whether papillary infarction is pathogenetically related to microinvasion is unknown and warrants further investigation.