Pattern of Bone Destruction GEOGRAPHIC BONE DESTRUCTION

Cause:(a) slow-growing usually benign tumor(b)rarely malignant: plasma cell myeloma, metastasis(c) infection: granulomatous osteomyelitis

well-defined smooth / irregular margin

short zone of transition

MOTH-EATEN BONE DESTRUCTION

Cause:(a) rapidly growing malignant bone tumor(b) osteomyelitis

less well defined / demarcated lesional margin

longer zone of transition

mnemonic:H LEMMONo Histiocytosis Xo Lymphomao Ewing sarcomao Metastasiso Multiple myelomao Osteomyelitiso Neuroblastoma

PERMEATIVE BONE DESTRUCTION

Cause:aggressive bone tumor with rapid growth potential (eg, Ewing sarcoma)

poorly demarcated lesion imperceptibly merging with uninvolved bone

long zone of transition

Size, Shape, and Margin of Bone Lesion

Primary malignant tumors are larger than benign tumors

elongated lesion (= greatest diameter of >1.5 times the least diameter): Ewing sarcoma, histiocytic lymphoma, chondrosarcoma, angiosarcoma

sclerotic margin (= reaction of host tissue to tumor)

Tumor Position in Transverse Plane CENTRAL MEDULLARY LESION

o Enchondromao Solitary bone cyst

ECCENTRIC MEDULLARY LESION o Giant cell tumoro Osteogenic sarcoma, chondrosarcoma, fibrosarcomao Chondromyxoid fibroma

CORTICAL LESION o Nonossifying fibromao Osteoid osteoma

PERIOSTEAL / JUXTACORTICAL LESION o Juxtacortical chondroma / osteosarcomao Osteochondromao Parosteal osteogenic sarcoma

Tumor Position in Longitudinal Plane EPIPHYSEAL LESION

o Chondroblastoma (prior to closure of growth plate)o Intraosseous ganglion, subchondral cysto Giant cell tumor (originating in metaphysis)o Clear cell chondrosarcomao Fibrous dysplasiao Abscess

mnemonic:CAGGIEo Chondroblastomao Aneurysmal bone cysto Giant cell tumoro Geodeo Infectiono Eosinophilic granuloma

[after 40 years of age throw out “CEA†and insert metastases / myeloma]

METAPHYSEAL LESION o Nonossifying fibroma (close to growth plate)o Chondromyxoid fibroma (abutting growth plate)o Solitary bone cysto Osteochondromao Brodie abscesso Osteogenic sarcoma, chondrosarcoma

DIAPHYSEAL LESION o Round cell tumor (eg, Ewing sarcoma)o Nonossifying fibromao Solitary bone cysto Aneurysmal bone cysto Enchondromao Osteoblastomao Fibrous dysplasia

mnemonic:FEMALEo Fibrous dysplasiao Eosinophilic granulomao Metastasiso Adamantinoma

o Leukemia, Lymphomao Ewing sarcoma

Tumors Localizing to Hematopoietic Marrow Metastases Plasma cell myeloma Ewing sarcoma Histiocytic lymphoma