Full-term pregnancy despite severe hypophosphatemia caused by tumor-induced osteomalacia.

A woman in her 30s with a history of multiple bone fractures unexpectedly became pregnant and delivered a full-term baby through cesarean section, despite suffering from excruciating pain without any apparent cause or specific treatment. The patient was referred to our endocrine clinic following childbirth. Blood tests revealed a life-threatening low level of serum phosphate, normal 25-hydroxy vitamin D concentration, low TmP/GFR ratio, and elevated FGF23 levels. A PET/CT scan with Gallium-68 Dotatate identified an abnormal tumor in the right calcaneus. Her FGF23 level returned to normal soon after surgical removal of the tumor, which was confirmed to be chondroblastoma. Her child's cognitive and motor skills typically developed from the newborn to preschool age. He exhibited excellent long-term growth, without any signs of rickets.