"From the tip to the deep of the iceberg": Parametrial involvement in endometriosis

Deep endometriosis (DE) can be localized in the parametrium, a complex bilateral anatomical structure, sometimes necessitating intricate surgical intervention due to the potential involvement of autonomic nerves, uterine artery, and ureter. If endometriotic ovarian cysts have been considered metaphorically representative of "the tip of the iceberg" concerning concealed DE lesions, it is reasonable to assert that parametrial lesions should be construed as the most profound region of this iceberg. Also, based on a subdual clinical presentation, a comprehensive diagnostic parametrial evaluation becomes imperative to strategize optimal management for patients with suspected DE. Recently, the ULTRAPARAMETRENDO studies aimed to evaluate the role of transvaginal ultrasound for parametrial endometriosis, showing distinctive features, such as a mild hypoechoic appearance, starry morphology, irregular margins, and limited vascularization. The impact of medical therapy on parametrial lesions has not been described in the current literature, primarily due to the lack of adequate detection at imaging. The extension of DE into the parametrium poses significant challenges during the surgical approach, thereby increasing the risk of intra- and postoperative complications, mainly if performed by centers with low expertise and following multiple surgical procedures where parametrial involvement has gone unrecognized. Over time, the principles of nerve-sparing surgery have been incorporated into the surgical DE treatment to minimize iatrogenic damage and potentially reduce the risk of functional complications.