Question mark form of uterus: a simple sonographic sign associated with the presence of adenomyosis

Adenomyosis as the presence of ectopic endometrial glands and stroma within the myometrium is an elusive condition that is challenging to diagnose due to the similarity between its clinical symptoms and ultrasound characteristics and those of other frequent benign conditions such as leiomyomatosis1. Over recent years, transvaginal sonography (TVS) has been recommended as an appropriate tool for visualization of adenomyosis, with a sensitivity of 65–81% and a specificity of 65–100%2. We performed a prospective study between January 2012 and January 2014 including 50 symptomatic fertile women who were scheduled to undergo elective hysterectomy because of symptoms of endometriosis/adenomyosis. Adenomyosis was diagnosed on TVS, in accordance with previous studies3, 4, in the presence of one or more of the following criteria: heterogeneous myometrium, irregular cystic areas, hypoechoic linear striations, asymmetry of uterine walls and poor definition of the endometrial–myometrial junctional zone (JZ). Moreover, a novel sign, which we called ‘question mark form of uterus’, was observed. The sign was present when the uterine corpus was flexed backward, the fundus of the uterus was facing the posterior pelvic compartment and the cervix was directed anteriorly towards the urinary bladder (Figure 1). Histological evaluation revealed the prevalence of adenomyosis to be 48% (24/50). We found a good level of agreement between histology and TVS in the diagnosis of adenomyosis (κ = 0.72 (95% CI, 0.53–0.90); P < 0.0001), with a percentage agreement of 86% (43/50). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of diagnosis by TVS were 83%, 88%, 87% and 85%, respectively. The question mark form of uterus alone had a specificity and sensitivity of 93% and 75%, respectively. It was observed in 18/24 (75%) women with histological adenomyosis and in 2/26 (7.7%) women without adenomyosis. Following inclusion of the question mark form of uterus in the criteria for diagnosis of adenomyosis, the sensitivity, specificity, PPV and NPV were 92%, 88%, 88% and 92%, respectively. With this novel sign, kappa analysis showed a good level of agreement between diagnosis of adenomyosis by TVS and by histology (κ = 0.80 (95% CI, 0.64–0.96); P < 0.0001), with a percentage agreement of 90% (45/50). Despite the recent recommendation of TVS examination for the diagnosis of adenomyosis, variable accuracy of sonography, due to differences in the selected main criteria, has been reported. Moreover, TVS is associated with considerable observer variation and its use in diagnosing adenomyosis requires substantial experience. To improve accuracy in diagnosing adenomyosis by TVS, specific criteria were introduced. Reinhold et al. demonstrated that a JZ thickness > 12 mm is highly predictive of adenomyosis and that an increased thickness of the posterior JZ of the uterus on magnetic resonance imaging is correlated with invasion of the basal endometrium into the inner myometrium in women with diffuse adenomyosis3. Other studies suggest that smooth muscle proliferation and hyperplasia in the JZ may precede the outgrowth of endometrial cells and adenomyosis4, 5. Adenomyosis is often diagnosed in women only after they have undergone hysterectomy because of heavy menstrual bleeding and/or pain, and its prevalence still varies widely. Consequently, the need remains for a marker to improve the diagnosis of adenomyosis. The new ultrasonographic sign, which in our study was characterized by a high prevalence (75%) in women with adenomyosis and a high specificity (93%), should be useful diagnostically in cases of clinical suspicion of adenomyosis and should help differentiate this from other uterine pathologies. N. Di Donato*†, V. Bertoldo†, G. Montanari†, L. Zannoni†, G. Caprara‡ and R. Seracchioli† †Minimally Invasive Gynecological Surgery Unit, S. Orsola-Malpighi Hospital, University of Bologna, Via Massarenti 13, 40138 Bologna, Italy; ‡Department of Anatomo-Pathology, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy *Correspondence. (e-mail: [email protected])