Primary Hypertrophic Osteoarthropathy: A Case Series

Abstract Primary hypertrophic osteoarthropathy (PHOA) is a rare genetic disorder defined by digital clubbing, periostosis of long bones, and musculoskeletal pain. Differentiating it from secondary hypertrophic osteoarthropathy, which is associated with pulmonary or cardiac disease, is essential to avoid misdiagnosis and inappropriate treatment. We report a retrospective series of four adult male patients presenting with joint pain and clubbing. All underwent systematic evaluation to exclude secondary causes, including chest imaging, echocardiography, and autoimmune screening. Radiographs of the long bones were performed to confirm periosteal new bone formation. All four patients demonstrated typical clinical and radiological features of PHOA with absence of systemic inflammation or secondary pathology. Joint pain was the predominant symptom, with radiographs confirming cortical thickening and periosteal reaction. Management was primarily symptomatic: all patients received non-steroidal anti-inflammatory drugs (NSAIDs), and two were additionally treated with oral alendronate. Both of these patients reported improved pain control and functional mobility during follow-up. None required corticosteroids or disease-modifying antirheumatic drugs. PHOA remains an underrecognized cause of clubbing and musculoskeletal pain and can mimic inflammatory arthritides. Careful exclusion of secondary causes combined with recognition of distinctive radiographic features is crucial for accurate diagnosis. Although curative therapy is lacking, conservative treatment with NSAIDs provides symptomatic benefit, while bisphosphonates may offer additional pain relief in selected patients. Increased clinical awareness can help prevent misclassification and ensure appropriate long-term management.