Vanishing Bone Disease of the Thoracic Cage: Challenges in the Management of a Rare Entity

BACKGROUND/OBJECTIVE: Vanishing bone disease (VBD) is a rare entity, characterized by massive osteolysis and lymphovascular proliferation. Our objective was to report the case of a 22-year-old man who presented with VBD of the ribs and the challenges involved with its management in this location. CASE REPORT: A 22-year-old man presented with left-sided chest and back pain. An x-ray revealed that the fourth to sixth ribs on the left side of the chest were missing. The erythrocyte sedimentation rate was normal (5 mm/h; normal value, <10 mm/h), ruling out overt infectious and inflammatory pathology. A positron emission tomography-computed tomography scan excluded an underlying malignancy. Findings of serum protein electrophoresis did not show an M band. Normal levels of calcium (9.0 mg/dL; normal range, 8.3-10.4 mg/dL) and parathyroid hormone (38 pg/mL; normal range, 8-74 pg/mL) excluded primary hyperparathyroidism as a cause for osteolysis. A computed tomography scan of the chest revealed only lytic destruction and resorption of the fourth to sixth ribs on the left side. A diagnosis of VBD was made. A biopsy was deferred owing to the location of the disease involving the thoracic cage that could cause permanent lymphatic leakage. He was administered parenteral zoledronate 4 mg monthly for 3 months and subsequently once every 3 months for the next 2 years with subcutaneous interferon alfa-2b 6 MIU thrice weekly initially, then twice a week, and subsequently tapered to once every 10 days. On the follow-up at 3 years, he remained stable, with no further osteolysis or radiographic progression of the disease. DISCUSSION/CONCLUSION: VBD may present diagnostic and therapeutic challenges; the abovementioned patient was diagnosed with VBD after excluding secondary causes of osteolysis. Although a high index of suspicion is required to diagnose VBD, it also mandates close monitoring and follow-up.