Amenorrhoea with XY karyotype postbone marrow transplant.

A 17-year-old girl presented with secondary amenorrhoea. She developed normal age-appropriate secondary sexual characteristics and attained menarche at the age of 13 years. One year following her menarche, she was diagnosed with acute myeloid leukaemia and was treated with chemotherapy, total body radiation and bone marrow transplant with complete remission. The matched donor was her elder male sibling. Her evaluation for secondary amenorrhoea included full hormonal analysis and pelvic ultrasound scan. These suggested hypergonadotrophic hypogonadism with a normal uterus and ovaries. Peripheral leucocyte karyotype as part of routine hypogonadism workup was found to be 46 XY. The differential diagnosis of Swyer syndrome, which entails surgical removal of gonads due to the high risk of gonadoblastoma, was raised initially before reviewing the laboratory results of previous chromosomal analysis. Considering her medical history, the amenorrhoea was finally attributed to ovarian insufficiency due to chemotherapy and radiotherapy. The 46 XY karyotyping could be explained by the bone marrow transplant received from her donor brother. Hypogonadism causing amenorrhoea is commonly encountered after chemoradiotherapy. Pretreatment and post-treatment chromosomal analysis is essential in such cases. Karyotyping could be misleading especially if the patient suffered from graft-versus-host reaction post gender mismatched bone marrow transplant.