The patient’s age and clinical presentation are very helpful in predicting the diagnosis in musculoskeletal tumors and greatly aid in the interpretation of the imaging studies. Following are typical ages for common bone tumors:
3–10 years: Langerhans cell histiocytosis, unicameral bone cyst, osteomyelitis
10–15 years: nonossifying fibroma, chondroblastoma, osteosarcoma, Ewing sarcoma
15–20 years: osteosarcoma, osteoid osteoma
20–30 years: giant cell tumor
30–50 years: metastatic carcinoma, malignant fibrous histiocytoma (MFH) and fibrosarcoma of bone, lymphoma in bone
>50 years: metastatic carcinoma, multiple myeloma, chondrosarcoma, Paget disease, Paget sarcoma, MFH and fibrosarcoma of bone, lymphoma in bone
The presence or absence of a history of pain can aid in the diagnosis of bone tumors. Many benign indolent tumors are detected incidentally during unrelated radiographic evaluation, whereas benign aggressive and malignant bone tumors are almost always painful.
Location in Bone, Skeletal Distribution
The location of a tumor in bone is of great significance. Each region of bone has biologic properties that predispose it to different tumors. Location in bone is described in two axes: longitudinal and axial. Longitudinal location refers to the epiphysis, metaphysis, or diaphysis of bone.
Although it is generally more important to recognize the location within bone of a tumor, in some cases knowing the particular affected bone can aid in diagnosis. Following are examples of tumors with distinctive skeletal distributions.
Pattern of Bone Lysis and Zone of Transition, Periosteal Reaction
PATTERN OF BONE LYSIS AND ZONE OF TRANSITION
Tumor margins, that is the interface between tumor and normal bone, are highly predictive of the aggressiveness of the tumor. Margins are described with two parameters: by the pattern of lysis and by the width of the zone of transition into normal bone. Bone lysis can be geographic, motheaten, or permeative. Geographic lysis represents a single focus of bone destruction. Motheaten and permeative patterns of lysis are produced by multiple small destructive foci of tumor. The zone of transition can be narrow, reflecting indolent growth, or wide, reflecting more rapid growth. Tumors with geographic lysis can have a narrow or a wide zone of transition. Tumors with motheaten and permeative lysis, by definition, have a wide zone of transition.