May Be Caused by

 Common

Degenerative arthritic cyst

Geode

Gouty erosion

Infectious arthritis

Metastases

Multiple myeloma

Mycetoma

Neuropathic erosion

Psoriatic erosion

Rheumatoid erosion

Sarcoidosis

Tuberculosis

 Uncommon

Amyloidosis

Enchondroma

Enchondromatosis

Hemophilia

Hereditary multiple exostoses

Hydatid disease

Jackhammer operator disease

Maffucci syndrome

Osteopathia striata

Osteopoikilosis

Pigmented villonodular synovitis

Synovial sarcoma

Synovial-type hemangiomatosis

Synovial-type lymphangiomatosis