PLEURAL EFFUSION CAUSED BY POLYOSTOTIC FIBROUS DYSPLASIA INVOLV- ING THE RIBS, THE STERNUM AND THE THORACIC SPINE ASSOCIATED WITH MULTIPLE CYSTIC DEGENERATIONS – A CASE REPORT PLEURALNA EFUZIJA PROUZROKOVANA POLIOSTOTSKOM FIBROZNOM DISPLAZIJOM SA ZAHVATANJEM REBARA, STERNUMA I TORAKALNE KIČME PRAĆ

Introduction. Fibrous dysplasia is a noninherited benign skeletal disorder associated with abnormal bone development. Single bone involvement, the monostotic form, accounts for 70 – 80% of cases, while the polyostotic form, with multiple bone involvement, accounts for 20 – 30% of cases. Cystic degeneration and occasional aneurysmal bone cyst formation may be found in fibrous dysplasia lesions, particularly in the costal lesions. Case Report. A 51-year-old man presented with acute shortness of breath after sustaining simple chest wall injury. Chest computed tomography showed multiple massive osteolytic rib lesions, as well as a massive left-sided pleural effusion with compression atelectasis of the lung parenchyma. Osteolytic lesions of the anterior 2nd and 7th thoracic vertebral body were found, along with a well defined osteolytic lesion in the body of the sternum. Video-assisted thoracoscopy of the left pleural space was performed and frozen sections, collected using endoscopic biopsy forceps of the cystic wall and solid parts of the tumors, were sent for ex tempore histopathological analysis. Results showed fibrous dysplasia with suspected malignancy. Talc pleurodesis was performed based on the obtained results. At present, the patient is asymptomatic with his daily routine uninterrupted by his medical condition. Conclusion. Treatment of pleural effusion caused by a cyst rupture of unresectable degenerated polyostotic fibrous dysplasia of the ribs represents a surgical challenge. Surgical drainage of the cysts followed by chemical pleurodesis seems to be a reasonable solution in cases where pulmonary functions are impacted by combined effects of pleural effusion and cystic compression.