= HYPERTROPHIC PULMONARY OSTEOARTHROPATHY (HPO) = MARIE-BAMBERGER DISEASE

= paraneoplastic syndrome

Etiology:

1. Release of vasodilators which are not metabolized by lung
2. Increased flow through AV shunts
3. Reflex peripheral vasodilation (vagal impulses)
4. Hormones: estrogen, growth hormone, prostaglandin

Histo: round cell infiltration of the outer fibrous layer of periosteum followed by new bone proliferation

1. THORACIC CAUSES
   1. malignant tumor (0.7–12%): bronchogenic carcinoma (88%), mesothelioma, lymphoma, pulmonary metastasis from osteogenic sarcoma, melanoma, renal cell carcinoma, breast cancer
      • 4–17% of patients with bronchogenic carcinoma may develop HPO!
   2. benign tumor: benign pleural fibroma, tumor of ribs, thymoma, esophageal leiomyoma, pulmonary hemangioma, pulmonary congenital cyst
   3. chronic infection / inflammation: pulmonary abscess, bronchiectasis, blastomycosis, TB (very rare); cystic fibrosis, interstitial fibrosis
   4. cyanotic congenital heart disease with R-to-L shunt
2. EXTRATHORACIC CAUSES (less common)
   1. GI tract: ulcerative colitis, amebic + bacillary dysentery, intestinal TB, Whipple disease, Crohn disease, gastric ulcer, bowel lymphoma, gastric carcinoma
   2. liver disease: biliary + alcoholic cirrhosis, posthepatic cirrhosis, chronic active hepatitis, bile duct carcinoma, benign bile duct stricture, amyloidosis, liver abscess
   3. undifferentiated nasopharyngeal carcinoma, pancreatic carcinoma, chronic myelogenous leukemia

• burning pain, painful swelling of limbs, and stiffness of joints: ankles (88%), wrists (83%), knees (75%), elbows (17%), shoulders (10%), fingers (7%)
• peripheral neurovascular disorders: local cyanosis, areas of increased sweating, paresthesia, chronic erythema, flushing + blanching of skin
• hippocratic fingers + toes (clubbing)
• hypertrophy of extremities (soft-tissue swelling)

Location: tibia + fibula (75%), radius + ulna (80%), proximal phalanges (60%), femur (50%), metacarpus and metatarsus (40%), humerus + distal phalanges (25%), pelvis (5%); unilateral (rare)

• Spine, pelvis, ribs usually spared!

Site: in diametaphyseal regions

• cortical thickening
• lamellar periosteal proliferation of new bone, at first smooth then undulating + rough
  Site: most conspicuous on concavity of long bones (dorsal + medial aspects)
• soft-tissue swelling (“clubbing”) of distal phalanges

Bone scan (reveals changes early with greater sensitivity + clarity):

• “parallel track” / “double stripe” / “tramline” sign = patchy linear diffusely increased symmetric uptake along cortical margins of metaphysis + diaphysis of tubular bones ← periostitis
• increased periarticular uptake ← synovitis
• scapular involvement in ⅔
• mandible ± maxilla abnormal in 40%

Prognosis: treatment of underlying condition leads to remission of symptoms often within 24 hours + regression of radiographic findings in months

DDx:

1. Pachydermoperiostosis (self-limited, adolescence, autosomal dominant, M >F)
2. Metastases (axial skeleton, focal asymmetric distribution)
   

   Differences between 1° and 2° HPT

   Skeletal Findings 1° HPT 2° HPT Osteopenia, diffuse present present Osteosclerosis, regional / diffuse rare common Bone resorption common common Brown tumor common less common Soft-tissue calcification not infrequent common Chondrocalcinosis not infrequent rare

3. Chronic vascular insufficiency
4. Thyroid acropachy
5. Hypervitaminosis A