A case report of X-linked hypophosphatemia combined with primary hyperparathyroidism

Abstract

Both hypophosphatemic osteomalacia and primary hyperparathyroidism (PHPT) can lead to hypophosphatemia, but their simultaneous occurrence in the same patient is exceedingly rare. This article reports a case of a 43-year-old female patient whose primary clinical manifestations included pain in the lumbosacral and scapular regions, restricted mobility, and biochemical findings of decreased serum phosphate levels with normal parathyroid hormone (PTH) levels. The patient's symptoms improved after treatment with active vitamin D supplementation, although neutral phosphate supplements were not administered. Eight years later, the patient's symptoms progressively worsened. Further investigations revealed elevated PTH levels and worsening hypophosphatemia. Neck contrast-enhanced ultrasonography and parathyroid radionuclide imaging both indicated nodules in the right parathyroid gland. Postoperative pathological examination confirmed the diagnosis of parathyroid adenoma. Whole-exome sequencing identified a heterozygous deletion in exon 11 of the PHEX gene, consistent with a diagnosis of X-linked hypophosphatemia (XLH).

Keywords: X-linked hypophosphatemia; bone pain; hypophosphatemic osteomalacia; parathyroidectomy; primary hyperparathyroidism.

Figure 1

Bone scintigraphy. (A) Bone scintigraphy 10 years ago showed increased metabolism in whole body bones and joints, and increased spot-like metabolism in ribs, clavicle and pelvis, which was consistent with osteomalacia. (B) Bone scintigraphy in 2023 showed obvious concentration of axial bone nuclides in the whole body, with typical necktie sign and beaded rib changes. Nuclide concentration was evident in shoulder joints, pelvis, sacroiliac joints and spine.