Adnexal mass in early pregnancy — structured oral station (12 minutes)

Opening prompt — "How would you characterise this mass?"

Model response — say it in this order: [1][2]

• "I would describe the mass in IOTA terminology — size in three dimensions, locularity, solid components, papillary projections, acoustic shadows, ascites and a colour Doppler score — and then apply the IOTA Simple Rules."
• "The Simple Rules are five B features that predict benignity and five M features that predict malignancy. One or more M and no B means malignant; the reverse means benign; both or neither is inconclusive, and I would then use the ADNEX model or expert subjective assessment."
• "In the Timmerman prospective validation of 1938 masses, the Simple Rules were conclusive in 77% and gave a sensitivity of 92% and specificity of 96%. Where inconclusive, expert subjective assessment outperformed the Risk of Malignancy Index."[1]

Probe 1 — "The registrar asks whether to send CA-125, AFP, hCG and inhibin."

• "I would not routinely send a tumour marker panel in pregnancy. CA-125 is expressed by peritoneum, decidua and amniotic fluid and rises physiologically; AFP, hCG and inhibin are produced by the pregnancy itself. Mid-range values are non-informative."
• "I would trust the imaging. If I needed a second-line test, it would be non-contrast MRI — first-trimester MRI has not been associated with fetal harm in the Ray cohort, but gadolinium at any gestation has been associated with stillbirth, neonatal death and rheumatological outcomes."[4]

Probe 2 — "She has known endometriosis. The mass has papillary projections with flow."

• "This is the classic decidualised endometrioma — progesterone-driven stromal change producing vascular papillary projections that mimic the M features of malignancy. It is the great mimic in this topic."
• "In the Barcroft pregnancy-specific IOTA two-step pilot of 291 pregnant women, decidualisation occurred in 31.1% of endometriomas and resolved in 89.5% by the first postnatal scan. ADNEX misclassified 34% of benign masses as malignant, over half of which were decidualised endometriomas."
• "Management is to resist surgery, use expert subjective assessment and serial imaging, and rescan postnatally. I would not refer her to oncology on these features alone."[4]

Probe 3 — "She re-presents at 16 weeks with sudden severe right iliac fossa pain and vomiting."

• "This is ovarian torsion until proven otherwise. The history and the known mass make the diagnosis; imaging is supportive but I would not delay theatre for it."
• "Analgesia, IV access, bloods, nil by mouth, anaesthetic and theatre. Laparoscopic detorsion with ovarian conservation — a dusky torted ovary often recovers, and oophorectomy is reserved for confirmed necrosis."
• "In Dvash's cohort of torsion in pregnancy, live birth was 92.5% and preterm delivery 19.4%, the latter driven mainly by multiple pregnancy. Almost half of torsion cases in pregnancy follow IVF or ovulation induction."[5]

Probe 4 — "If she needs elective surgery, when and how?"

• "Elective surgery belongs in the second trimester — after organogenesis and while access is still good. The counterweight is that necessary surgery is never delayed for gestational age; a torsion at 32 weeks still goes to theatre."
• "Laparoscopy is preferred over laparotomy. In the Cagino meta-analysis, laparoscopy showed no significant increase in spontaneous abortion (OR 1.53, 95% CI 0.67 to 3.52) or preterm delivery (OR 0.95, 95% CI 0.47 to 1.89), with a shorter length of stay."
• "Technique: open or optical entry above the fundus, insufflation 12 to 15 mmHg or less, capnography, left lateral tilt, minimal uterine manipulation, and thromboprophylaxis."[6]

Probe 5 — "She asks whether the surgery will harm her baby."

• "Surgery in pregnancy is generally safe — the attributable risk is low — but I would give her the absolute numbers. In the Balinskaite cohort of 6.5 million pregnancies, non-obstetric surgery was associated with one additional stillbirth per 287 operations, one additional preterm delivery per 31, one additional low-birthweight baby per 39, one additional caesarean per 25, and one additional long inpatient stay per 50."
• "I would frame it honestly: the absolute risk to her pregnancy is small, and the operation is being done for a good reason — but these are the numbers."[6]

Probe 6 — "What if the mass had M features and ascites from the start?"

• "Then this is no longer a watch-and-wait problem. I would refer to gynaecological oncology, stage with non-contrast MRI, and plan a multidisciplinary approach informed by ESGO and INCIP principles — exactly as I would outside pregnancy."
• "The malignancy rate among adnexal masses that come to surgery in pregnancy is only around 1%, and the borderline ovarian tumour dominates in this age group. The plan would usually be fertility-sparing where feasible."[2]