<prompt> Ovarian tumor involving retroperitoneal lymph nodes is seen in stageStage IIBStage IIIAStage IIIBStage IIIC  <response>: -Ovarian cancer staging: Stage III Tumor involves 1 or both ovaries or fallopian tubes or primary peritoneal cancer with cytologically or histologically confirmed spread to the peritoneum outside the pelvis andor metastasis to the retroperitoneal lymph nodes. -Stage IIIa: Involvement of retroperitoneal lymph nodes andor microscopic metastasis beyond the pelvis. -Stage IIIa1: positive retroperitoneal lymph nodes only Stage IIIa1i: metastasis 10mm Stage IIIa1ii: metastasis or 10mm -Stage IIIa2: Microscopic, extrapelvic peritoneal extension with or without positive retroperitoneal lymph nodes. Reference : textbook of gynaecology Sheila balakrishnan, 2nd edition, pg no: 277 p 