case_images: PMC10896610_01
case_images: Plasma phosphate levels over time. Dotted line indicates lower level of normal reference range, 0.75 mmol/L. Red arrows indicate the administration of intravenous iron (at month 14, FCM was administered; subsequent infusions at months 28, 34, and 39 were ferric derisomaltose).
case_images: crg-2024-0018-0001-536136_F01.jpg
case_images: PMC10896610_01_crg-2024-0018-0001-536136_F01.jpg
case_images: F1
case_images: Over 2 years, four intravenous iron infusions had been administered (shown in Fig. 1). The nadir phosphate level of 0.31 mmol/L, shown in Figure 1, had occurred prior to receiving any iron infusions.
case_images: a Bone scintigraphy at initial work-up shows diffusely increased osteoblastic activity throughout the axial skeleton. There are multiple bilateral insufficiency fractures in the distal tibia and feet (arrows), multiple bilateral nondisplaced rib fractures (arrows), suspected looser zones in the bilateral proximal humeral diaphysis (arrows), and anterior wedge compression fractures of L1 and L2. b Maximum intensity projection from PET scan following intravenous injection of 172MBq of Ga68-DOTATATE. There is intense uptake in a small soft tissue nodule posterior to the right knee, measuring 10 x 15 mm (arrow). c Bone scintigraphy 2 years post-removal of PMT demonstrates significant improvement in the previously demonstrated metabolic pattern of uptake through the axial and appendicular skeleton, with now largely physiological activity.
case_images: crg-2024-0018-0001-536136_F02.jpg
case_images: PMC10896610_01_crg-2024-0018-0001-536136_F02.jpg
case_images: F2
case_images: Bone scintigraphy, shown in Figure 2a, was consistent with osteomalacia. DOTATATE PET scan, shown in Figure 2b, identified an avid 10 x 15 mm soft tissue nodule posterior to the right knee. Two years post-surgery, there was significant improvement in the bone scan appearances, with now largely physiologic activity (Fig. 2c).
case_images: a Hematoxylin and eosin stain, intermediate power. Tissue from the resected soft tissue lesion demonstrated a highly vascular lesion with spindle cells in short fascicles with zones of cytoplasmic clearing, occasional foamy macrophages, and scattered aggregates of osteoclast-like giant cells. b FGF23 immunohistochemistry, intermediate power. FGF23 immunohistochemistry was positive with typical perinuclear dot-like expression.
case_images: crg-2024-0018-0001-536136_F03.jpg
case_images: PMC10896610_01_crg-2024-0018-0001-536136_F03.jpg
case_images: F3
case_images: Histopathology shown in Figure 3 demonstrated a highly vascular lesion with spindle cells in short fascicles (Fig. 3a), positive for FGF23 on immunohistochemistry (Fig. 3b).