Solitary Bone Lesion in a Young Adult Errol S. Lloyd, MD, and Harry C. Press, Jr., MD Washington, DC
Clinical History A 17-year-old white male complained of recent development of pain in his right hip. The pain was not severe but was constant. Physical examination and laboratory studies were otherwise normal. X-ray of the hip was obtained (Figure 1). There were no other Roentgen findings.
Radiographic Findings A single 2 cm well-circumscribed lesion, with a radiolucent center and a sclerotic margin, is noted at the greater trochanter of the femur. Small stippled calcifications are noted in the matrix of the lesion. There is no associated periosteal elevation or soft tissue mass (Figure 1). Requests for reprints should be addressed to Dr. Harry C. Press, Jr., Department of Radiology, Howard University Hospital, Washington, DC 20060.
What is the Most Likely Diagnosis? 1. 2. 3. 4.
Chondromyxoid fibroma Unicameral bone cyst Chondrosarcoma Chondroblastoma
cartilaginous tumor tends to calcify and will appear stippled on x-ray examination; the osteoid matrix appears more uniformly dense or sclerotic; and while
Differential Diagnosis In the evaluation of bone tumors, the most important information that the radiologist can give the clinician is whether a tumor is benign or malignant. In general, a benign lesion has a welldefined margin with regards to the surrounding bone, and this margin may be sclerotic. The sclerosis visualized is bone laid down reactively by the normal host bone. On the other hand, a malignant lesion shows poorly defined margins or frankly destructive changes that may break through the cortex and extend into the soft tissues. The tumor matrix also gives histological information. Thus, the chondroid matrix of a
JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 70, NO. 9, 1978
Figure 1 AP view of the right hip and proximal femur shows a 2 cm radiolucent lesion (arrow) in the greater trochanter. 681
the fibrous matrix does not calcify, it will be uniformly radiolucent. All of the above lesions except the bone cyst are cartilage tumors.
Chondromyxoid Fibroma Usually occuring in the second and third decades but affecting any age, chondromyxoid fibroma is a rare cartilaginous tumor that almost always arises in the metaphysis of a large cylindrical bone. The lesion is usually eccentric in location and, because it is slow growing, evokes a thin margin of reactive sclerosis around its mostly radiolucent center. It also has a tendency to be expansile and to show scalloped borders roentgenographically. It is more radiolucent and shows less stippled calcification than chondroblastoma.I The lesion is usually benign but if large may erode the cortex; malignant degeneration has occurred. It is most commonly found in the upper tibia and small bones of the hands and feet. It is rare in the humerus.2 Because the present lesion is located in the epiphysis of the greater trochanter and has a moderately sclerotic margin, this diagnosis is unlikely.
Unicameral Bone Cyst This is a collection of gas or fluid enclosed in a capsule usually lined with fibrous tissue. There is a 3:1 male to female preponderance and 80 percent of these lesions are said to occur between ages three and 14 years.1 They occur at the metaphysis of a long bone, but with growth the cyst appears to
migrate toward the shaft. Those cysts located closer to the epiphyseal plate are said to be more active (in regards to their growth potential) than those nearer the shaft. The most common site for this lesion is the proximal humerus. Pain is the usual presenting symptom and is secondary to fracture or infarction causing involvement of the periosteal sensory structure. The etiology of bone cysts is controversial. The true cysts arise de novo and are found in young individuals while other cysts may arise secondary to degeneration in proliferative processes or hematomas and occur in older age groups. The lipoma is the commonest precursor of such bone cysts.2 X-ray appearance is that of a lesion with well-defined limits but, depending on the size, there may be thinning of the cortex and even fracture. Trabeculation is commonly seen and is secondary to ridges in the wall of the lesion. The location of the present lesion does not make bone cyst the most likely choice.
Chondrosarcoma This is the third most common primary malignant bone tumor, and it is almost totally cartilaginous with only a minimal amount of supportive collagenous tissue.3 The lesion may be primary or develop from other cartilage tumors such as enchondromas or osteochondromas. The average patient age is 35 but these tumors may occur from age 10-76 years.2 The majority arise at the metaphysis of the distal
femur, proximal tibia, or humerus. They also occur frequently in the pelvis. The only consistent symptom is pain which eventually becomes severe. Roentgenographically, the tumor more commonly appears as a destructive lesion that exhibits flocculent calcification because of its calcified chondroid matrix. There may be an associated soft tissue mass with calcifications following extension of the tumor through the cortex of the bone. Early lesions, however, especially those arising from enchondromas or other benign cartilage tumors, do not show the aggressive signs of malignancy. Fortunately, these are less common and it is unlikely that the present lesion would be a chondrosarcoma.
Chondroblastoma This is the correct diagnosis. This lesion usually measures 1 to 4 cm in diameter and it consistently arises in an epiphysis; however, if large, it may affect the metaphysis as well. It usually affects the age group of 10-25 years, and because it causes pain near a joint, it may be misdiagnosed as arthritis. It is quite rare and constitutes less than one percent of bone tumors. On x-ray it usually appears as a well-demarcated ovoid or circular lesion with a sclerotic rim. Stippled calcifications may appear in the matrix of the lesion. The great majority of these tumors are benign but rarely they may enlarge and even protrude into the joint space. Malignant degeneration has been reported.4
Literature Cited 1. Greenfield GB: Radiology of Bone Diseases. Toronto, JB Lippincott, 1975, pp 424-467 2. Benign and Malignant Bone Tumors. In Armed Forces Institute of Pathology (Washington, DC): Radiologic Pathology WorkshopGovernment Printing Office, 1974, section 1, pp 39-42, section 2, pp 18-22 3. Aegerter E, Kirkpatrick J: Orthopedic Diseases. Philadelphia, WB Saunders, 1975, pp 433-440 4. Copeland MM, Geschickter CF: Tumors of Bone and Soft Tissue. Chicago, Year Book Medical Publishers, 1965, pp 279-298 682
JOURNAL OF THE NATIONAiL MEDICAL ASSOCIATION, VOL. 70, NO. 9, 1978
Clinical History A 17-year-old white male complained of recent development of pain in his right hip. The pain was not severe but was constant. Physical examination and laboratory studies were otherwise normal. X-ray of the hip was obtained (Figure 1). There were no other Roentgen findings.
Radiographic Findings A single 2 cm well-circumscribed lesion, with a radiolucent center and a sclerotic margin, is noted at the greater trochanter of the femur. Small stippled calcifications are noted in the matrix of the lesion. There is no associated periosteal elevation or soft tissue mass (Figure 1). Requests for reprints should be addressed to Dr. Harry C. Press, Jr., Department of Radiology, Howard University Hospital, Washington, DC 20060.
What is the Most Likely Diagnosis? 1. 2. 3. 4.
Chondromyxoid fibroma Unicameral bone cyst Chondrosarcoma Chondroblastoma
cartilaginous tumor tends to calcify and will appear stippled on x-ray examination; the osteoid matrix appears more uniformly dense or sclerotic; and while
Differential Diagnosis In the evaluation of bone tumors, the most important information that the radiologist can give the clinician is whether a tumor is benign or malignant. In general, a benign lesion has a welldefined margin with regards to the surrounding bone, and this margin may be sclerotic. The sclerosis visualized is bone laid down reactively by the normal host bone. On the other hand, a malignant lesion shows poorly defined margins or frankly destructive changes that may break through the cortex and extend into the soft tissues. The tumor matrix also gives histological information. Thus, the chondroid matrix of a
JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 70, NO. 9, 1978
Figure 1 AP view of the right hip and proximal femur shows a 2 cm radiolucent lesion (arrow) in the greater trochanter. 681
the fibrous matrix does not calcify, it will be uniformly radiolucent. All of the above lesions except the bone cyst are cartilage tumors.
Chondromyxoid Fibroma Usually occuring in the second and third decades but affecting any age, chondromyxoid fibroma is a rare cartilaginous tumor that almost always arises in the metaphysis of a large cylindrical bone. The lesion is usually eccentric in location and, because it is slow growing, evokes a thin margin of reactive sclerosis around its mostly radiolucent center. It also has a tendency to be expansile and to show scalloped borders roentgenographically. It is more radiolucent and shows less stippled calcification than chondroblastoma.I The lesion is usually benign but if large may erode the cortex; malignant degeneration has occurred. It is most commonly found in the upper tibia and small bones of the hands and feet. It is rare in the humerus.2 Because the present lesion is located in the epiphysis of the greater trochanter and has a moderately sclerotic margin, this diagnosis is unlikely.
Unicameral Bone Cyst This is a collection of gas or fluid enclosed in a capsule usually lined with fibrous tissue. There is a 3:1 male to female preponderance and 80 percent of these lesions are said to occur between ages three and 14 years.1 They occur at the metaphysis of a long bone, but with growth the cyst appears to
migrate toward the shaft. Those cysts located closer to the epiphyseal plate are said to be more active (in regards to their growth potential) than those nearer the shaft. The most common site for this lesion is the proximal humerus. Pain is the usual presenting symptom and is secondary to fracture or infarction causing involvement of the periosteal sensory structure. The etiology of bone cysts is controversial. The true cysts arise de novo and are found in young individuals while other cysts may arise secondary to degeneration in proliferative processes or hematomas and occur in older age groups. The lipoma is the commonest precursor of such bone cysts.2 X-ray appearance is that of a lesion with well-defined limits but, depending on the size, there may be thinning of the cortex and even fracture. Trabeculation is commonly seen and is secondary to ridges in the wall of the lesion. The location of the present lesion does not make bone cyst the most likely choice.
Chondrosarcoma This is the third most common primary malignant bone tumor, and it is almost totally cartilaginous with only a minimal amount of supportive collagenous tissue.3 The lesion may be primary or develop from other cartilage tumors such as enchondromas or osteochondromas. The average patient age is 35 but these tumors may occur from age 10-76 years.2 The majority arise at the metaphysis of the distal
femur, proximal tibia, or humerus. They also occur frequently in the pelvis. The only consistent symptom is pain which eventually becomes severe. Roentgenographically, the tumor more commonly appears as a destructive lesion that exhibits flocculent calcification because of its calcified chondroid matrix. There may be an associated soft tissue mass with calcifications following extension of the tumor through the cortex of the bone. Early lesions, however, especially those arising from enchondromas or other benign cartilage tumors, do not show the aggressive signs of malignancy. Fortunately, these are less common and it is unlikely that the present lesion would be a chondrosarcoma.
Chondroblastoma This is the correct diagnosis. This lesion usually measures 1 to 4 cm in diameter and it consistently arises in an epiphysis; however, if large, it may affect the metaphysis as well. It usually affects the age group of 10-25 years, and because it causes pain near a joint, it may be misdiagnosed as arthritis. It is quite rare and constitutes less than one percent of bone tumors. On x-ray it usually appears as a well-demarcated ovoid or circular lesion with a sclerotic rim. Stippled calcifications may appear in the matrix of the lesion. The great majority of these tumors are benign but rarely they may enlarge and even protrude into the joint space. Malignant degeneration has been reported.4
Literature Cited 1. Greenfield GB: Radiology of Bone Diseases. Toronto, JB Lippincott, 1975, pp 424-467 2. Benign and Malignant Bone Tumors. In Armed Forces Institute of Pathology (Washington, DC): Radiologic Pathology WorkshopGovernment Printing Office, 1974, section 1, pp 39-42, section 2, pp 18-22 3. Aegerter E, Kirkpatrick J: Orthopedic Diseases. Philadelphia, WB Saunders, 1975, pp 433-440 4. Copeland MM, Geschickter CF: Tumors of Bone and Soft Tissue. Chicago, Year Book Medical Publishers, 1965, pp 279-298 682
JOURNAL OF THE NATIONAiL MEDICAL ASSOCIATION, VOL. 70, NO. 9, 1978
