Skeletal Radiol (1991) 20:67-70
Skeletal Radiology
Case report 650 George B. Greenfield, M.D. 1' 2, Carlos Cardenas, M.D. 1' 2, Peter J. Dawson, M.D. 3, and Stephen Stenzler, M.D. 1 Department of Radiology, University of South Florida, Tampa, 2 Department of Radiology, H. Lee Moffitt Cancer Center and Research Institute, 3 Department of Pathology, University of South Florida, Tampa, Florida, USA
Clinical information
Radiological (imaging) studies
Fig. 1. An AP view of the right hip shows patchy sclerosis of the femoral head and irregularity of its articular surface. Hypertrophic spurs are also seen Fig. 2. MRI study: Coronal Tl-weighted (TR 800 ms, TE 20 ms) MR image shows homogeneous decreased signal intensity of the proximal end of the right femur, to a point below the intertrochanteric region
This 55-year-old man presented with a 5-year history of pain in the right hip on ambulation. The patient underwent bipolar arthroplasty of the right hip with the preoperative diagnosis of stage IV avascular necrosis. His past medical history was significant for core decompression of his left femoral head for stage II avascular necrosis. Preoperative physical examination revealed mild tenderness over the right greater trochanter. Range of motion was painful with right hip flexion of 90 ~ abduction of 30 ~ abduction of 30 ~ internal rotation of 5~ and external rotation of 20 ~ Roentgenograms of the right hip demonstrated sclerotic changes of the femoral head (Fig. 1), with irregularity of its articular surface and superimposed degenerative osteoarthritis of the hip. A magnetic resonance imaging (MRI) study o f the hips was obtained. Coronal T1weighted images demonstrated homogenous decreased signal intensity of the proximal end o f the right femur to a point below the level of the trochanters (Fig. 2) The patient underwent right bipolar hemiarthroplasty, and the femoral head was submitted to the pathology department for evaluation.
Address reprint requests to: G.B. Greenfield,
M.D., Department of Radiology, University of South Florida, Tampa, FL33612, USA 9 1991 International Skeletal Society
68
Diagnosis: Grade II chondrosareoma of the proximal end of the right femur T h e p r e o p e r a t i v e d i a g n o s i s was stage IV a v a s c u l a r necrosis o f the r i g h t
G.B. Greenfield et al. : Case report 650 f e m o r a l head. T h e r o e n t g e n o g r a p h i c features were suggestive o f a v a s c u l a r necrosis. T h e M R I features were suggestive o f an infiltrative p r o c e s s o f the m a r r o w .
Pathological studies
Fig. 3. Area of tumor necrosis mimicking ischemic necrosis (H & E, x 25) Fig. 4. Tumor tissue in the femoral head shows hypercellularity and nuclear pleomorphism (H & E, x 250)
Fig. 5. Hypercellular myxoid area in the femoral head ( H & E , x250) Fig. 6. Cellular detail of the tumor in the femoral head, showing a binucleate cell and nucleoli (H & E, x 400) Fig. 7. Residual tumor found in the femoral shaft at amputation. Note high cellularity, nucleoli, and a binucleate cell (H & E, x 320)
The pathological specimen consisted o f a f e m o r a l h e a d m e a s u r i n g 5.0 x 5.0 x 3.5 cm. T h e a r t i c u l a r surface was r o u g h e n e d a n d fissured. C u t section r e v e a l e d a p o o r l y d e m a r c a t -
G.B. Greenfieldet al. : Case report 650 ed, pale, slightly soft, pie-shaped area beneath the cortex similar to that found in avascular necrosis. Close inspection, however, revealed other irregular, pale areas scattered through the medullary portion of the femoral head, that were softer in consistency than the adjacent bone. Histologically, there was extensive replacement of the femoral head by nodules of neoplastic cartilage. There was considerable nuclear pleomorphism and frequent binucleate forms. Many nuclei had prominent nucleoli, and a rare mitosis was seen. Consultation with outside sources concurred with the diagnosis of grade II chondrosarcoma. Tumor extended to the distal surgical margin. The area that resembled avascular necrosis on the roentgenograms and in the gross specimen was in fact an area of necrotic chondrosarcoma (Figs. 3-7). Subsequently, the patient underwent a right hemipelvectomy. When the soft tissues were dissected away there was an area of dense fibrous tissue containing bony areas overlying the greater trochanter. The joint space contained several small fibrinous foreign bodies. Located within the medullary cavity were several, irregular, pale areas, the largest measuring 2 x 2 x 1 cm. Histologically these were similar in appearance to the tumor in the femoral head and were interpreted as residual chondrosarcoma, grade II (Fig. 7).
Discussion
Chondrosarcoma is the third most common primary malignant neoplasm of bone, after multiple myeloma and osteosarcoma [5]. Chondrosarcoma may develop in a preexisting cartilaginous lesion, such as an osteocartilaginous exostosis or enchondroma. Fewer than 5% of the lesions occur prior to the age of 20 years, with the average age being about 45years [5]. More than 80% of chondrosarcomas arise centrally if tumors arising from the femoral head, shoulder girdle, and upper segment of the humerus are included [5]. The pelvis and proximal ends of the femora account for 40% of chondrosarcomas. Chondrosarcomas of long bones arise in the metaphysis or dia-
69 metaphyseal region in approximately long bones at the epiphysis extending 90% of cases. Nearly all of the re- into the metaphysis. The femur and mainder are diaphyseal, with epiphy- the humerus are most frequently inseal lesions being distinctly rare [5]. volved. Chondrosarcoma usually has a Mesenchymal chondrosarcoma is slow clinical evolution [2]. The rare a rare tumor with a characteristic development of hematogenous me- histological appearance of cartilage tastasis often occurs late [2]. Patients and undifferentiated stromal cells. most often present with dull pain and Clinically, the average age of the palocal swelling of a few months' or tient is younger than that of the paeven several years' duration [2]. Men tient with conventional chondrosarare slightly more often affected than coma. Long-standing pain and swellwomen. Chondrosarcomas are cen- ing and a soft-tissue mass are typical tral, peripheral, or juxtacortical in findings. The tumor may involve any origin. Central chondrosarcoma is site in the skeleton. Radiologically, primarily a tumor of adulthood and the pattern varies. Expansion, perold age [2]. meative bone destruction, periosteal Grossly, these tumors have a car- new bone formation, and calcificatilaginous, shiny blue to gray appear- tion may all be seen. The younger ance. Chondrosarcoma will frequent- age of the patient should suggest the ly result in a combination of cortical diagnosis. This is an aggressive tuexpansion and thickening. These tu- mor with a poor prognosis. mors are nearly always lobulated. Dedifferentiated chondrosarcoCentral necrosis, liquefaction, or cyst ma is a highly malignant variant in formation are common, especially which a low-grade chondrosarcoma with larger masses. Flecks or nodules is associated with an anaplastic sarof calcification are noted frequently coma. The associated component is [5]. usually osteosarcoma, fibrosarcoma, Chondrosarcoma can be exceed- or malignant fibrous histiocytoma. It ingly difficult to diagnose histologi- occurs in approximately 10% of all cally. Suggestive features include hy- chondrosarcomas. Clinically, it afpercellularity, irregularity in size of fects older individuals. Pain, soft-tiscells and nuclei, multinucleated cells, sue mass, and pathological fractures and hyperchromatism of cells. An in- may occur. The skeletal distribution cisional biopsy is required to obtain is similar to that of conventional sufficient tissue and is usually man- chondrosarcoma. Radiologically, the datory due to the presence of inter- lesion is characterized by an osteolytspersed areas of necrosis. ic, intraosseous or extraosseous, softMost chondrosarcomas are low tissue mass without calcifications, asgrade, with more than 90% being sociated with an area that contains Broder's grade 1 or 2. Findings fa- calcifications. The latter represents voring malignancy include localized the low-grade portion of the tumor. pain large size of lesion, older age The aggressive portion may show groups, central location, soft-tissue "moth-eaten" bone destruction, extension, rapid growth, myxoid tis- soft-tissue invasion, and pathological sue, and radiographic evidence of ag- fracture. This is a highly malignant gressiveness [5]. tumor with a tendency to metastasize In addition to conventional chon- and a poor prognosis [3]. drosoma, clear cell chondrosarcoma, Plain films are nearly always mesenchymal chondrosarcoma, and helpful and often afford almost pathdedifferentiated chondrosarcoma ognomonic evidence of chondrosarhave been described. coma [2]. Radiologically, cartilage Clear-cell chondrosarcoma is a tissue is rapidly recognized by amorlow-grade malignant tumor charac- phous, punctate, small, flocculent, terized by cells with a centrally dense, irregular calcifications [3]. placed vesicular nucleus surrounded Most tumors will be larger than a few by clear cytoplasm. The major symp- centimeters at the time of diagnosis. tom is mild, localized pain, usually As the tumor enlarges and reaches of long duration. The age range is the cortical bone, it will either mainusually the 3rd and 5th decades. The tain its shape by expanding or penelesions are normally located in the trating the cortex or will conform to
70 the shape of the bone, growing linearly within the medullary canal [5]. The demonstration of the intraosseous extent of the tumor is most accurate with M R I [1]. Most often the margins of the tumor are poorly defined, especially when it is large or histologically a high-grade lesion. The low-grade and "borderline" chondrosarcoma may have a well-defined and distinct margin, with or without a sharply defined sclerotic rim. These radiographic features make the distinction from a benign lesion often difficult [5]. When the lesion is purely lytic and without mineralization of the matrix the radiographic appearance is frequently nonspecific. This is most common in high-grade lesions [5]. Erosion by tumor outstrips reactive new bone formation, causing cortical thinning [4]. Erosion or scalloping of the endosteal surface of the cortex is suggestive of malignancy. Cortical thickening and expansion of the lesion are often present in chondrosarcomas [5]. Although the lesion has a natural history that is highly variable and unpredictable, it will cause death if neglected or is inadequately treated [5]. This slowly growing tumor is often diagnosed late because of its insidious clinical presentation. Radiological and histological findings may be indistinguishable or only subtly different from those of benign lesions, leading all too often to misdiagnosis
G.B. Greenfield et al. : Case report 650 and inadequate treatment [5]. The resection of these tumors must be radical to avoid soft-tissue recurrence and to increase the chance of survival. Even though the clinical course is generally slow, with metastasis occurring rarely and usually late, this advantage is frequently negated by delays, difficulties, and errors in the diagnosis and treatment [5]. This case demonstrates the difficulty of making the diagnosis of chondrosarcoma on occasion with plain-film radiography. None of the typical radiographic features of chondrosarcoma were apparent in this case. The roentgenograms suggested findings of avascular necrosis and demonstrated degenerative osteoarthritis. The significance of distinguishing chondrosarcoma from benign tumors or avascular necrosis is reflected in the diminished survival of those patients misdiagnosed and inadequately treated. The combination of plain-film radiography with M R I may improve the sensitivity and specificity in the diagnosis. The T1weighted image showed a uniform low signal intensity to a level below the trochanters, which is consistent with replacement of marrow by tumor. The classical findings of avascular necrosis were not present. These would include an ischemic focus of high or low signal intensity and a peripheral low signal intensity band of demarcation.
In summary, a case is presented in which the conventional radiograph was suggestive of avascular necrosis. This impression remained unchanged in spite of an M R I examination that was more suggestive of replacement of marrow. The diagnosis of ischemic necrosis was strongly supported by the patient having previously established avascular necrosis in the opposite hip. The gross pathologic specimen showed only necrotic tumor, which mimicked avascular necrosis on the plain film. The importance of placing proper confidence in the M R I findings is thus emphasized. A classification and brief description of the various types of chondrosarcoma are included in the Discussion.
References 1. Bloem JL, Taminiau AH (1988) Radiologic staging of primary bone sarcoma: MR imaging, scintigraphy, angiography, and CT correlated with pathologic examination. Radiology 169 : 809 2. Dahlin DC, Unni KK (1986) Bone tumors, 4th edn. Charles C. Thomas, Springfield, p 227 3. Greenfield GB (1990) Radiologic of bone diseases, 5th edn. J.B. Lippincott, Philadelphia, p 584 4. Hudson TM (1987) Radiologic-pathologic correlation of musculoskeletal lesions. Williams and Wilkins, Baltimore, p 154 5. McLeod RA, Ferrucci JT, Taveras JM (1987) Revised edn. J.B. Lippincott, Philadelphia. Vol 5, 83:1
Skeletal Radiology
Case report 650 George B. Greenfield, M.D. 1' 2, Carlos Cardenas, M.D. 1' 2, Peter J. Dawson, M.D. 3, and Stephen Stenzler, M.D. 1 Department of Radiology, University of South Florida, Tampa, 2 Department of Radiology, H. Lee Moffitt Cancer Center and Research Institute, 3 Department of Pathology, University of South Florida, Tampa, Florida, USA
Clinical information
Radiological (imaging) studies
Fig. 1. An AP view of the right hip shows patchy sclerosis of the femoral head and irregularity of its articular surface. Hypertrophic spurs are also seen Fig. 2. MRI study: Coronal Tl-weighted (TR 800 ms, TE 20 ms) MR image shows homogeneous decreased signal intensity of the proximal end of the right femur, to a point below the intertrochanteric region
This 55-year-old man presented with a 5-year history of pain in the right hip on ambulation. The patient underwent bipolar arthroplasty of the right hip with the preoperative diagnosis of stage IV avascular necrosis. His past medical history was significant for core decompression of his left femoral head for stage II avascular necrosis. Preoperative physical examination revealed mild tenderness over the right greater trochanter. Range of motion was painful with right hip flexion of 90 ~ abduction of 30 ~ abduction of 30 ~ internal rotation of 5~ and external rotation of 20 ~ Roentgenograms of the right hip demonstrated sclerotic changes of the femoral head (Fig. 1), with irregularity of its articular surface and superimposed degenerative osteoarthritis of the hip. A magnetic resonance imaging (MRI) study o f the hips was obtained. Coronal T1weighted images demonstrated homogenous decreased signal intensity of the proximal end o f the right femur to a point below the level of the trochanters (Fig. 2) The patient underwent right bipolar hemiarthroplasty, and the femoral head was submitted to the pathology department for evaluation.
Address reprint requests to: G.B. Greenfield,
M.D., Department of Radiology, University of South Florida, Tampa, FL33612, USA 9 1991 International Skeletal Society
68
Diagnosis: Grade II chondrosareoma of the proximal end of the right femur T h e p r e o p e r a t i v e d i a g n o s i s was stage IV a v a s c u l a r necrosis o f the r i g h t
G.B. Greenfield et al. : Case report 650 f e m o r a l head. T h e r o e n t g e n o g r a p h i c features were suggestive o f a v a s c u l a r necrosis. T h e M R I features were suggestive o f an infiltrative p r o c e s s o f the m a r r o w .
Pathological studies
Fig. 3. Area of tumor necrosis mimicking ischemic necrosis (H & E, x 25) Fig. 4. Tumor tissue in the femoral head shows hypercellularity and nuclear pleomorphism (H & E, x 250)
Fig. 5. Hypercellular myxoid area in the femoral head ( H & E , x250) Fig. 6. Cellular detail of the tumor in the femoral head, showing a binucleate cell and nucleoli (H & E, x 400) Fig. 7. Residual tumor found in the femoral shaft at amputation. Note high cellularity, nucleoli, and a binucleate cell (H & E, x 320)
The pathological specimen consisted o f a f e m o r a l h e a d m e a s u r i n g 5.0 x 5.0 x 3.5 cm. T h e a r t i c u l a r surface was r o u g h e n e d a n d fissured. C u t section r e v e a l e d a p o o r l y d e m a r c a t -
G.B. Greenfieldet al. : Case report 650 ed, pale, slightly soft, pie-shaped area beneath the cortex similar to that found in avascular necrosis. Close inspection, however, revealed other irregular, pale areas scattered through the medullary portion of the femoral head, that were softer in consistency than the adjacent bone. Histologically, there was extensive replacement of the femoral head by nodules of neoplastic cartilage. There was considerable nuclear pleomorphism and frequent binucleate forms. Many nuclei had prominent nucleoli, and a rare mitosis was seen. Consultation with outside sources concurred with the diagnosis of grade II chondrosarcoma. Tumor extended to the distal surgical margin. The area that resembled avascular necrosis on the roentgenograms and in the gross specimen was in fact an area of necrotic chondrosarcoma (Figs. 3-7). Subsequently, the patient underwent a right hemipelvectomy. When the soft tissues were dissected away there was an area of dense fibrous tissue containing bony areas overlying the greater trochanter. The joint space contained several small fibrinous foreign bodies. Located within the medullary cavity were several, irregular, pale areas, the largest measuring 2 x 2 x 1 cm. Histologically these were similar in appearance to the tumor in the femoral head and were interpreted as residual chondrosarcoma, grade II (Fig. 7).
Discussion
Chondrosarcoma is the third most common primary malignant neoplasm of bone, after multiple myeloma and osteosarcoma [5]. Chondrosarcoma may develop in a preexisting cartilaginous lesion, such as an osteocartilaginous exostosis or enchondroma. Fewer than 5% of the lesions occur prior to the age of 20 years, with the average age being about 45years [5]. More than 80% of chondrosarcomas arise centrally if tumors arising from the femoral head, shoulder girdle, and upper segment of the humerus are included [5]. The pelvis and proximal ends of the femora account for 40% of chondrosarcomas. Chondrosarcomas of long bones arise in the metaphysis or dia-
69 metaphyseal region in approximately long bones at the epiphysis extending 90% of cases. Nearly all of the re- into the metaphysis. The femur and mainder are diaphyseal, with epiphy- the humerus are most frequently inseal lesions being distinctly rare [5]. volved. Chondrosarcoma usually has a Mesenchymal chondrosarcoma is slow clinical evolution [2]. The rare a rare tumor with a characteristic development of hematogenous me- histological appearance of cartilage tastasis often occurs late [2]. Patients and undifferentiated stromal cells. most often present with dull pain and Clinically, the average age of the palocal swelling of a few months' or tient is younger than that of the paeven several years' duration [2]. Men tient with conventional chondrosarare slightly more often affected than coma. Long-standing pain and swellwomen. Chondrosarcomas are cen- ing and a soft-tissue mass are typical tral, peripheral, or juxtacortical in findings. The tumor may involve any origin. Central chondrosarcoma is site in the skeleton. Radiologically, primarily a tumor of adulthood and the pattern varies. Expansion, perold age [2]. meative bone destruction, periosteal Grossly, these tumors have a car- new bone formation, and calcificatilaginous, shiny blue to gray appear- tion may all be seen. The younger ance. Chondrosarcoma will frequent- age of the patient should suggest the ly result in a combination of cortical diagnosis. This is an aggressive tuexpansion and thickening. These tu- mor with a poor prognosis. mors are nearly always lobulated. Dedifferentiated chondrosarcoCentral necrosis, liquefaction, or cyst ma is a highly malignant variant in formation are common, especially which a low-grade chondrosarcoma with larger masses. Flecks or nodules is associated with an anaplastic sarof calcification are noted frequently coma. The associated component is [5]. usually osteosarcoma, fibrosarcoma, Chondrosarcoma can be exceed- or malignant fibrous histiocytoma. It ingly difficult to diagnose histologi- occurs in approximately 10% of all cally. Suggestive features include hy- chondrosarcomas. Clinically, it afpercellularity, irregularity in size of fects older individuals. Pain, soft-tiscells and nuclei, multinucleated cells, sue mass, and pathological fractures and hyperchromatism of cells. An in- may occur. The skeletal distribution cisional biopsy is required to obtain is similar to that of conventional sufficient tissue and is usually man- chondrosarcoma. Radiologically, the datory due to the presence of inter- lesion is characterized by an osteolytspersed areas of necrosis. ic, intraosseous or extraosseous, softMost chondrosarcomas are low tissue mass without calcifications, asgrade, with more than 90% being sociated with an area that contains Broder's grade 1 or 2. Findings fa- calcifications. The latter represents voring malignancy include localized the low-grade portion of the tumor. pain large size of lesion, older age The aggressive portion may show groups, central location, soft-tissue "moth-eaten" bone destruction, extension, rapid growth, myxoid tis- soft-tissue invasion, and pathological sue, and radiographic evidence of ag- fracture. This is a highly malignant gressiveness [5]. tumor with a tendency to metastasize In addition to conventional chon- and a poor prognosis [3]. drosoma, clear cell chondrosarcoma, Plain films are nearly always mesenchymal chondrosarcoma, and helpful and often afford almost pathdedifferentiated chondrosarcoma ognomonic evidence of chondrosarhave been described. coma [2]. Radiologically, cartilage Clear-cell chondrosarcoma is a tissue is rapidly recognized by amorlow-grade malignant tumor charac- phous, punctate, small, flocculent, terized by cells with a centrally dense, irregular calcifications [3]. placed vesicular nucleus surrounded Most tumors will be larger than a few by clear cytoplasm. The major symp- centimeters at the time of diagnosis. tom is mild, localized pain, usually As the tumor enlarges and reaches of long duration. The age range is the cortical bone, it will either mainusually the 3rd and 5th decades. The tain its shape by expanding or penelesions are normally located in the trating the cortex or will conform to
70 the shape of the bone, growing linearly within the medullary canal [5]. The demonstration of the intraosseous extent of the tumor is most accurate with M R I [1]. Most often the margins of the tumor are poorly defined, especially when it is large or histologically a high-grade lesion. The low-grade and "borderline" chondrosarcoma may have a well-defined and distinct margin, with or without a sharply defined sclerotic rim. These radiographic features make the distinction from a benign lesion often difficult [5]. When the lesion is purely lytic and without mineralization of the matrix the radiographic appearance is frequently nonspecific. This is most common in high-grade lesions [5]. Erosion by tumor outstrips reactive new bone formation, causing cortical thinning [4]. Erosion or scalloping of the endosteal surface of the cortex is suggestive of malignancy. Cortical thickening and expansion of the lesion are often present in chondrosarcomas [5]. Although the lesion has a natural history that is highly variable and unpredictable, it will cause death if neglected or is inadequately treated [5]. This slowly growing tumor is often diagnosed late because of its insidious clinical presentation. Radiological and histological findings may be indistinguishable or only subtly different from those of benign lesions, leading all too often to misdiagnosis
G.B. Greenfield et al. : Case report 650 and inadequate treatment [5]. The resection of these tumors must be radical to avoid soft-tissue recurrence and to increase the chance of survival. Even though the clinical course is generally slow, with metastasis occurring rarely and usually late, this advantage is frequently negated by delays, difficulties, and errors in the diagnosis and treatment [5]. This case demonstrates the difficulty of making the diagnosis of chondrosarcoma on occasion with plain-film radiography. None of the typical radiographic features of chondrosarcoma were apparent in this case. The roentgenograms suggested findings of avascular necrosis and demonstrated degenerative osteoarthritis. The significance of distinguishing chondrosarcoma from benign tumors or avascular necrosis is reflected in the diminished survival of those patients misdiagnosed and inadequately treated. The combination of plain-film radiography with M R I may improve the sensitivity and specificity in the diagnosis. The T1weighted image showed a uniform low signal intensity to a level below the trochanters, which is consistent with replacement of marrow by tumor. The classical findings of avascular necrosis were not present. These would include an ischemic focus of high or low signal intensity and a peripheral low signal intensity band of demarcation.
In summary, a case is presented in which the conventional radiograph was suggestive of avascular necrosis. This impression remained unchanged in spite of an M R I examination that was more suggestive of replacement of marrow. The diagnosis of ischemic necrosis was strongly supported by the patient having previously established avascular necrosis in the opposite hip. The gross pathologic specimen showed only necrotic tumor, which mimicked avascular necrosis on the plain film. The importance of placing proper confidence in the M R I findings is thus emphasized. A classification and brief description of the various types of chondrosarcoma are included in the Discussion.
References 1. Bloem JL, Taminiau AH (1988) Radiologic staging of primary bone sarcoma: MR imaging, scintigraphy, angiography, and CT correlated with pathologic examination. Radiology 169 : 809 2. Dahlin DC, Unni KK (1986) Bone tumors, 4th edn. Charles C. Thomas, Springfield, p 227 3. Greenfield GB (1990) Radiologic of bone diseases, 5th edn. J.B. Lippincott, Philadelphia, p 584 4. Hudson TM (1987) Radiologic-pathologic correlation of musculoskeletal lesions. Williams and Wilkins, Baltimore, p 154 5. McLeod RA, Ferrucci JT, Taveras JM (1987) Revised edn. J.B. Lippincott, Philadelphia. Vol 5, 83:1
