Struma ovarii is the presence of thyroid tissue as the
major cellular component in an ovarian tumour. Papillary
carcinoma in struma ovarii is exceptionally rare. We
report a case of papillary carcinoma in struma ovarii in a
postmenopausal 51-year-old female who initially presented clinically with hyperthyroidism. Serology, however, did not confirm hyperthyroidism. During a re-admission to our hospital later that year she appeared to have had periods of postmenopausal vaginal haemorrhage. An abdominal mass was located by radiography and pathological investigation revealed a papillary carcinoma in struma ovarii. Some striking features of this unusual presentation of importance to the internal medicine physician are discussed.