Endocrine Abstracts

Section 1: Case history : A 20-year-old Bangladeshi female presented to her GP with an 18-month history of nonspecific abdominal pain. She is nulligravida, not sexually active and reports no intermenstrual bleeding, dysmenorrhoea, menorrhagia or dysuria. Past medical history includes obesity, OSA and anosmia.

Section 2: Investigations : The patient underwent a TVUS which demonstrated a large (158 × 84 × 156 mm) multiloculated lesion with a solid vascular component (55 × 29 × 17 mm). Subsequent MRI pelvis confirmed a complex loculated right ovarian mass and excluded any malignant features. Ca125 18 units/ml; Ca19.9 60.5 units/ml; CEA 2.6 units/ml. The patient underwent a laparoscopic ovarian cystectomy. There was multiple cyst rupture during surgery with both solid and fluid components, as well as omental samples, sent for cyto- and histopathology. Left ovary was of normal appearance.

Section 3: Results and treatment : Histopathological examination demonstrated an ovarian teratoma containing a thyroid tissue predominance, struma ovarii, with evidence of peritoneal dissemination, termed peritoneal strumosis. Thyroid function tests were within normal range (T4 15.2 pmol/l; TSH 1.15 mU/l). Ultrasound neck demonstrated mild generalised increase in thyroid parenchymal volume with some underlying colloid micronodular change. The patient underwent a total thyroidectomy to facilitate the probable need for conventional dose radioiodine ablation and therapy, guided by thyroglobulin, to target the ectopic thyroid tissue. Post-thyroidectomy I-123 uptake scan demonstrated residual thyroidal tissue in the central compartment of the neck as well as a 30 mm right sided intensely iodine avid ovarian mass consistent with a struma ovarii. The left ovary also demonstrated iodine uptake which may or may not be physiological. Repeat surgery on the right ovary was opted against due to the subsequent predicted increase in radioiodine uptake by the left ovary during radioiodine ablation. To preserve fertility options, the patient underwent oocyte storage prior to I-131 ablation. This is the extent of management at time of submission.

Section 4: Conclusions and points for discussion : Struma ovarii is a very rare ovarian pathology which comprises <5% of all ovarian teratomas. In exceptionally rare cases, histologically benign appearing struma ovarii exhibits peritoneal dissemination, termed peritoneal strumosis. It is thought that peritoneal strumosis may represent metastasis from a high differentiated follicular carcinoma arising in struma ovarii. The rarity of this case inherently limits the evidence base for its management, which is further nuanced by the patient’s desire to preserve future fertility options and discussion remains about the best option for ongoing care.