= progressive slow bone-resorptive disease

Histo: proliferation + hyperplasia of smooth muscle cells of synovial arterioles

• progressive osteolysis of carpal + tarsal bones
• thinned pointed proximal ends of metacarpals + metatarsals
• elbows show same type of destruction
• bathyrocephalic depression of base of skull

DDx:

1. Massive osteolysis = Gorham disease (local destruction of contiguous bones, usually not affecting hands / feet)
2. Mutilating forms of rheumatoid arthritis
3. Tabes dorsalis
4. Leprosy
5. Syringomyelia
6. Scleroderma
7. Raynaud disease
8. Regional posttraumatic osteolysis
9. Ulceromutilating acropathy
10. Mutilating forms of rheumatoid arthritis
11. Acrodynia mutilante (nonhereditary)