DIAGNOSIS: Hypertrophic pulmonary osteoarthropathy due to carcinoma of the right lung

Ann Saudi Med 2006;26(6):489-491 The radiograph of the knees (Figure 1) shows periosteal thickening at the metadiaphysis of the distal femur and proximal tibia and fibula on both sides. The knee joint space is maintained and there are no periarticular erosions. The radiograph of ankles (Figure 2) reveals a similar periosteal reaction in the distal tibia and fibula, which is most conspicuous along the dorsal aspect with a normal appearance of the joints. The differential diagnosis for this pattern of bilateral periosteal reaction includes hypertrophic pulmonary osteoarthropathy (HOA), pachydermoperiostosis, thyroid acropachy and vascular insufficiency. The chest radiograph (Figure 3) reveals a mass without air bronchogram in the right paracardiac region and right pleural effusion. CT of the chest (Figure 4) shows the mass as a lobulated lesion in the right middle and lower lobe abutting the mediastinum associated with right pleural effusion. The features in chest imaging are those of a lung carcinoma. The combination of all radiological findings leads us to the diagnosis of hypertrophic pulmonary osteoarthropathy (HOA) due to carcinoma of the right lung. Biopsy of the lung mass revealed the lesion to be a moderately differentiated adenocarcinoma.