A 52-year-old woman comes to the office due to worsening pain in her hands and ankles for the past several months. She also has had a nonproductive cough, anorexia, and unintentional weight loss. The patient has no prior medical conditions. Physical examination shows digital clubbing and bony tenderness affecting the wrists, hands, and ankles. There is localized right upper lung wheezing. Chest x-ray reveals an irregular mass in the peripheral right lung. Laboratory studies reveal mild normocytic anemia and normal serum electrolytes and calcium. Which of the following is the most likely cause of this patient's extremity pain?

Question

A 52-year-old woman comes to the office due to worsening pain in her hands and ankles for the past several months.  She also has had a nonproductive cough, anorexia, and unintentional weight loss.  The patient has no prior medical conditions.  Physical examination shows digital clubbing and bony tenderness affecting the wrists, hands, and ankles.  There is localized right upper lung wheezing.  Chest x-ray reveals an irregular mass in the peripheral right lung.  Laboratory studies reveal mild normocytic anemia and normal serum electrolytes and calcium.  Which of the following is the most likely cause of this patient's extremity pain?

Quizplus · Accepted Answer

11ec160b_3a5d_5835_9249_8ff021a0b0b2_MD0001_00 This patient has hypertrophic osteoarthropathy (HOA), a syndrome characterized by painful bone and soft tissue enlargement in the distal extremities. Manifestations of HOA include clubbing (enlargement of the distal phalanges with flattening of the nail fold), painful arthropathy, periostosis (tender thickening of the periosteum) of long bones, and joint effusions. HOA commonly occurs in the setting of pulmonary malignancy, primarily adenocarcinoma, which characteristically arises in the lung periphery and is the most common primary lung cancer in nonsmokers. HOA can also occur with lung metastasis, certain nonmalignant lung disorders (eg, cystic fibrosis, bronchiectasis), and cyanotic heart disease. Under normal conditions, megakaryocytes released from the bone marrow migrate to the pulmonary circulation, where fragmentation releases platelets into the bloodstream. However, in HOA, disruption of the normal pulmonary circulation leads to arteriovenous shunting and allows megakaryocytes to bypass the lungs into the systemic circulation. Upon lodging in the peripheral tissues (eg, distal digital bone), they release platelet-derived growth factor and vascular endothelial growth factor, leading to fibrovascular hyperplasia and abnormal bone formation. (Choice B) Avascular necrosis (AVN) of bone is characterized by degeneration of cortical bone due to loss of arterial circulation. It usually occurs in locations that have limited or retrograde blood supply (eg, head of femur); other than the scaphoid and lunate, it is rare in the hands and wrists. Also, this patient has no risk factors (eg, glucocorticoid use) for AVN. (Choice C) Osteolytic skeletal metastasis is common in lung adenocarcinoma but typically affects the spine, pelvis, ribs, and long bones rather than distal limbs. Calcium is often but not always elevated. (Choice D) Generalized bone mineral loss is characteristic of osteoporosis, which is typically painless in the absence of fracture. Educational objective: Hypertrophic osteoarthropathy is characterized by abnormal growth of new bone and presents with digital clubbing, painful arthropathy, periostosis of long bones, and joint effusions. It commonly occurs in the setting of pulmonary malignancy, primarily adenocarcinoma, other lung disorders (eg, cystic fibrosis, bronchiectasis), and cyanotic heart disease.

A 52-Year-Old Woman Comes to the Office Due to Worsening