S5783 The Silent Signal: When Bones Reveal an Underlying Liver Condition (A Case of Hypertrophic Osteoarthropathy Secondary to Liver Cirrhosis)

Introduction: Hypertrophic osteoarthropathy (HOA) is a syndrome of periostosis, digital clubbing, and joint pain. It has 2 forms: primary (genetic) and secondary (associated with various diseases, particularly pulmonary malignancies). Its occurrence with liver cirrhosis is exceedingly rare. We present a case of HOA as the initial manifestation of underlying cirrhosis. Case Description/Methods: A 45-year-old man with morbid obesity (BMI 53) and peptic ulcer disease presented with 4 days of right leg pain, swelling, and a ruptured blister. He reported 6 months of fatigue, arthralgia, and weight gain, and had been on hydroxychloroquine for 6 months without improvement. Family history included rheumatoid arthritis and lupus. Exam showed a superficial wound with serous drainage, erythema, and mild tenderness, along with PIP and DIP joint hypertrophy and hand nodules. In the ED, he was afebrile with stable vitals except for mild hypertension (155/101). Labs showed alkaline phosphatase 416, albumin 2.8, international normalized ratio 1.55, bilirubin 1.5, platelets 197K (MELD-Na 16), ESR 120, CRP 12.3, and HbA1c 8.2%. A computed tomography (CT)of the leg revealed extensive heterotopic ossification and periosteal bone growth in the right tibia and fibula consistent with HOA. CT abdomen showed cirrhotic morphology and portal hypertension. Autoimmune workup revealed positive ANA but negative anti-smooth muscle and anti-LKM antibodies. Hepatitis panel was negative. CT chest ruled out thoracic malignancy, and echocardiogram was normal. HOA was presumed secondary to cirrhosis after excluding pulmonary, cardiac, and autoimmune causes. He was discharged with rheumatology and hepatology follow-ups for presumed MASH-related cirrhosis. Discussion: Although HOA is typically linked to lung cancer and cardiac shunts, hepatic causes are rare. The pathogenesis may involve shunting of megakaryocytes or elevated VEGF inducing periosteal changes. The tibia and fibula are often first affected, though other long bones may be involved. This case highlights the importance of considering liver disease in HOA’s differential, especially when pulmonary and autoimmune causes are excluded. Recognizing this rare extrahepatic sign may aid earlier detection of cirrhosis in at-risk patients.