A Question Well Put

A CLINICAL PROBLEM-SOLVING article by Brendan Reilly from Weill Cornell Medical Center, New York.
A 51-year-old woman with a history of hypertension and depression reported progressively worsening pain in the left thigh over a period of several months, which had made her unable to walk for the past week. She reported having undergone hip surgery 6 months earlier to repair a “stress fracture” of her painful left leg.
At that time, a bone survey revealed generalized osteopenia, confirmed by dual-energy x-ray absorptiometry.
Postoperatively, the patient was treated with vitamin D2 weekly for 3 months and monthly thereafter, as well as physical therapy. She recovered from her surgery and was able to resume walking, but her pain continued.
Physical examination was unremarkable except for severe pain with any movement of the patient's left thigh and tenderness to palpation of both upper arms, several ribs bilaterally, and her lower spine.
Radiographs showed generalized osteopenia, multiple rib fractures, and transverse lytic lesions in the left femur and pubic ramus.
The serum phosphorus level was 1.1 mg per deciliter (normal range, 2.5 to 4.5). The serum level of 1,25-dihydroxyvitamin D was 15 pg per milliliter (normal range, 15 to 60).
Hypophosphatemia, most often caused by renal phosphate wasting, is a potent stimulus of the production of 1,25-dihydroxyvitamin D. Thus, the low-normal serum level of 1,25-dihydroxyvitamin D is surprising. Combined with severe hypophosphatemia, it suggests rare disorders that cause both renal phosphate wasting and down-regulation of 25-hydroxyvitamin D-1α-hydroxylase.

タイトルは、John Deweyの"A question well put is half resolved." から。答えの、hemangiopericytoma-like tumorは、hemangiopericytoma自体、非常に珍しい疾患で私も知らなかった。日本語訳も、血管外皮腫、血管周皮細胞腫、血管外皮細胞腫、血管周皮腫と様々で、定まっていない。

Reference

• Thomas O. Carpenter, M.D. Oncogenic Osteomalacia — A Complex Dance of Factors N Engl J Med 2003; 348:1705-1708