Abstract: Background and purpose: Ovarian lymphoma (OL) is usually misdiagnosed as ovarian cancer with bulk lymph node invasion (OC-BLN), and vice versa. Therefore, to distinguish these two types of disease, we compared their clinical characteristics in this study. Methods: This study retrospectively reviewed 14 OL and 14 OCBLN patients from Fudan University Shanghai Cancer Center and Shanghai Eighth People’s Hospital. The clinical characteristics, image and laboratory examination data were compared. Results: There was no significant difference in age, symptom, fever, weight loss and volume of ascitic fluid between the two groups. Comparing with OC-BLN, OL patients have larger tumor in ovaries ［(13.04±5.94) cm vs (7.78±6.38) cm, P=0.033］, and higher percentage of solid ovarian tumor (85.71% vs 28.5%, P=0.006). Lactate dehydrogenase(LDH)/CA125 was higher in OL (7.66±8.03) than OC-BLN (0.31±0.27, P=0.009). Using LDH/CA125 to diagnose OL, area under the curve (AUC) was 0.952. When the threshold value was set at 1, the sensitivity and specificity was 91.7% and 100%, respectively. Conclusion: OL and OC-BLN are easily to be misdiagnosed. OL has larger and more solid tumor than OC-BLN. LDH/CA125 can help to distinguish these two diseases and guide clinical decision making.

Key words: Ovarian lymphoma, Ovarian cancer, Clinic characteristics, CA125, Lactate dehydrogenase