Adnexal mass Meaning of adnexal mass: A lump in tissue near the uterus, usually in the ovary or fallopian tube. Adnexal masses include ovarian cysts , ectopic (tubal) pregnancies, and benign (not cancer) or malignant (cancer) tumors. Also See: Adrenal gland Atypical hyperplasia Antiemetic Adenosine deaminase-deficient severe combined immunodeficiency AP23573 Angiofibroma Antigen-presenting cell vaccine Anti-inflammatory Action study Antineoplastic