Pathology of the adnexal mass

An "adnexal mass" is a common specimen encountered in the daily pathology practice. Although most are benign, the incidence of malignancy increases with age, and approximately 30% are malignant in postmenopausal females. Herein we describe the salient macroscopic and microscopic features of the most prevalent adnexal masses. The entities are separated based on patients' age into premenopausal and postmenopausal, with further subdivision into non-neoplastic lesions, benign and malignant neoplasms, and those of uncertain behavior. For each entity, a brief differential diagnosis is discussed and for the malignant neoplasms, tables highlighting the key immunohistochemical differences that may be helpful are provided.