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Erschienen in:
13.05.2015 | Clinical Quiz
A rare manifestation of renal osteodystrophy in a non-compliant child on hemodialysis: Answers
Erschienen in: Pediatric Nephrology | Ausgabe 9/2016
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Answer 1: Brown tumor:
Brown tumors are rare focal giant cell lesions of the bone caused by hyperparathyroidism (HPT). Although brown tumors can present at different locations and with unexpected clinical manifestations, common areas of involvement are the mandible, sternum, pelvis, ribs and femur. It is a lytic but benign bone tumor, commonly present in patients with secondary HPT due to chronic kidney disease (CKD), mainly in those with untreated renal osteodystrophy (ROD).
Answer 2: Secondary HPT due to ROD:
Chronic HPT results in a severe metabolic bone disease called ROD, which is a multifactorial disorder of bone remodeling [1‐3]. There are three histological forms of ROD: predominant osteomalacia, predominant osteitis fibrosa and, most commonly, a mixed pattern. Brown tumor formation develops only in the osteitis fibrosa cystica form [2, 3]. It is caused by a clinical consequence of untreated severe primary, secondary or tertiary HPT [4]. In the case of our patient, the cause of the brown tumor is secondary HPT. Secondary HPT is usually due to CKD and remains the main cause of morbidity in chronic hemodialysis patients [5].
Answer 3:
Numerous osteoclast-like giant cells, spindle-shaped fibrogenic stroma and hemorrhagic areas are seen during pathologic examination of this patient. Although the term “brown tumor” suggests an aggressive lesion, it is actually a benign lesion. In addition, the term “brown tumor” is derived from the characteristic appearance of brownish material within the lesion, which is caused by increased vascularity, hemorrhage and deposits of hemosiderin [6].