Mesenchymal hamartoma of the chest wall: radiologic manifestations with emphasis on cross-sectional imaging and histopathologic comparison.

PURPOSE: To describe the imaging features of chest wall mesenchymal hamartoma with emphasis on cross-sectional imaging and comparison with histopathologic results. MATERIALS AND METHODS: For 14 mesenchymal hamartomas of the chest wall in 12 children, radiologic studies (computed tomographic [CT] scans [n = 14], radiographs [n = 11], magnetic resonance [MR] images [n = 9], and bone scintigraphic images [n = 1]) were reviewed by four radiologists with consensus agreement. Clinical history was reviewed for patient demographics and symptoms at presentation. Radiologic studies were evaluated for lesion location, size, number of affected ribs, cortical irregularity or erosion, presence and type of matrix mineralization, lung hyperaeration adjacent to the lesion, degree and homogeneity of radionuclide uptake, and intrinsic characteristics on CT and MR images. RESULTS: Patients included seven male and five female children. Nine patients (75%) were younger than 1 year. Five patients had a chest wall mass; in the remaining seven, the lesion was discovered incidentally. All 14 lesions arose from ribs, 11 were located posteriorly, and 11 affected multiple contiguous ribs. Two patients had multifocal disease, each with two discrete lesions. Radiography in all cases revealed a large expansile rib lesion and an associated extrapleural soft-tissue mass, suggesting an aggressive process. Mineralization was seen in seven (64%) lesions at radiography and in 14 (100%) lesions at CT. Hemorrhagic cavities (secondary aneurysmal bone cyst [ABC] regions) were common, seen in nine (64%) lesions at CT and in four (80%) of five lesions imaged with T2-weighted MR imaging. CONCLUSION: Mesenchymal hamartoma of the chest wall may be recognized by its characteristic occurrence in infancy and cross-sectional imaging features of mineralization and hemorrhagic cystic (secondary ABC) components.     

Solid variant of aneurysmal bone cysts in long tubular bones: giant cell reparative granuloma

OBJECTIVE: The purpose of this study was to determine the age distribution, location, and imaging features of histologically proven solid variants of aneurysmal bone cysts in long tubular bones. MATERIALS AND METHODS: We performed a retrospective review of imaging studies of histologically proven solid aneurysmal bone cysts in long bones between 1961 and 2001. There were 30 cases comprising 29 radiographic, six CT, and eight MR imaging examinations. The lesions were evaluated for bone involved, location within a long bone, matrix, size, soft-tissue mass, and MR imaging characteristics. The imaging findings were correlated with the histologic findings. RESULTS: The patients were 17 females and 13 males ranging in age from 2 to 58 years (mean, 18 years). The bones involved were the femur (n = 10), the ulna (n = 7), the tibia (n = 7), the humerus (n = 2), the radius (n = 2), and the fibula (n = 2). The lesions were five juxtaarticular, 13 metaphyseal, one diametaphyseal, and 11 diaphyseal. The location was eccentric in 20 cases, of which two were intracortical and two periosteal, and central in 10. Lesion size varied between 1 and 7 cm. Thirty-three percent of lesions were nonaneurysmal. Four lesions were mineralized. A soft-tissue mass was present in four cases. Four lesions showed a permeative-lytic pattern simulating a malignant process. Unusual findings included periosteal reaction and development of a solid aneurysmal bone cyst in a preexisting fracture. MR imaging showed solid elements in all cases and pronounced edema in 50% of cases. CONCLUSION: Solid aneurysmal bone cyst is a reactive nonneoplastic bone lesion with varied imaging characteristics; one third of lesions are nonaneurysmal.     

Fluid-fluid level: a nonspecific finding in tumors of bone and soft tissue

Fluid-fluid levels have commonly been reported to occur in aneurysmal bone cysts but have also been seen in telangiectatic osteosarcoma, chondroblastoma, and giant cell tumor of bone. The authors reviewed their experience with nine bone and three soft-tissue tumors that showed fluid-fluid levels on computed tomographic or magnetic resonance images. The bone tumors included fibrous dysplasia, simple bone cyst, recurrent malignant fibrous histiocytoma of bone, two classical osteosarcomas, and four aneurysmal bone cysts. The soft-tissue tumors included soft-tissue hemangioma and two synovial sarcomas. Except for aneurysmal bone cysts, these types of tumors have not been reported to be associated with fluid-fluid levels. Radiologic-pathologic correlation was available in seven patients; in all seven, the fluid-fluid levels indicated prior hemorrhage. The authors conclude that the presence of fluid-fluid levels in bone or soft-tissue tumors cannot be considered diagnostic of any particular tumor.     

Osteoblastoma: clinical and radiologic findings in 98 new cases

The data on 98 new patients with osteoblastoma were studied. The clinical features of pain, scoliosis, and neurologic deficit were largely consistent with those in previous reports. Osteoblastoma is usually a lytic lesion originating in the medulla of bones with matrix ossification and mild surrounding sclerosis. Osteoblastoma of the spine demonstrated better tumor delineation in the vertebrae, and a bony rim on the soft-tissue side was seen less frequently than previously observed. Osteoblastoma of the talus frequently appears as a blister on the surface of the bone and is accompanied by osteoporosis. In the hands and feet, the radiographic appearance is often very similar to that of aneurysmal bone cyst and giant cell tumor. In the skull it strongly resembles a button sequestrum of bone. The origin and extent of the tumor, the presence of matrix mineralization, and tumor delineation depicted as a thin bony shell are often better appreciated on computed tomographic (CT) scans. In addition, CT can demonstrate both edema and atrophy of the surrounding soft tissues. At magnetic resonance (MR) imaging, osteoblastoma demonstrates signal intensities similar to those of other bone neoplasms. In addition to the advantages offered by CT, MR imaging can help differentiate tumor tissue from accompanying edema.     

颅骨动脉瘤样骨囊肿的影像学表现

目的：探讨颅骨动脉瘤样骨囊肿的影像学表现，提高对颅骨动脉瘤样骨囊肿的认识。资料与方法：搜集经手术病理证实的4例颅骨动脉瘤样骨囊肿，全部病例均作了CT平扫与MRI检查，其中1例摄有颅骨平片，1例MR／增强扫描，1例DSA检查。结果：4例颅骨动脉瘤样骨囊肿中，1例位于左蝶骨嵴和左眶骨处，2例位于左颞骨。1例位于右额骨。CT上均表现为不同程度的膨胀性吹气球样溶骨破坏区，密度不均匀；MRI示有出血、囊变及液面，T1WI和R2WI上呈混杂信号，1例增强后示肿瘤实质和邻近脑膜强化；血管造影示血管有推移改变。结论：颅骨动脉瘤样骨囊肿的影像学表现有一定的特征性，CT与MRI相结合能提示诊断，并有助于评价周围结构。     

血管扩张型骨肉瘤的临床、影像和病理分析

目的 进一步分析血管扩张型骨肉瘤的临床、影像及病理学的诊断特征和诊断方法,以加深对其认识和提高诊断水平.方法 回顾性分析10例经病理证实的血管扩张型骨肉瘤资料并结合文献深入分析其临床、影像和病理学表现.10例均行X线平片和MR检查,其中2例同时行CT检查.结果 10例血管扩张型骨肉瘤发生于股骨下端5例、股骨颈1例、肱骨上端和胫骨上段各2例.10例X线平片和2例CT 图像上肿瘤表现为溶骨性骨质破坏,伴骨体轻度膨胀4例,骨破坏区大部分边缘不清且无硬化边,均有Codman三角和大小不一的软组织肿块,肿块内无明显肿瘤性成骨;10例MRI上肿瘤大部或完全由多发囊腔构成,均出现骨膜反应,其中7例囊腔内见少量散在的较小液-液平面.10例病理学上肿瘤均有类似动脉瘤样骨囊肿的血腔结构,但囊壁或囊间隔中见恶性肿瘤细胞以及数量不一的肿瘤性成骨组织,其中6例仅见少量灶状的肿瘤性骨样组织.结论 影像学上类似动脉瘤样骨囊肿的表现和一般恶性骨肿瘤生长方式的特点,以及病理上的血腔结构和囊壁或囊间隔内的恶性肿瘤细胞是血管扩张型骨肉瘤的影像和病理学诊断特征.密切结合临床、影像和病理分析有助于临床及时正确诊断.     

Imaging of soft-tissue myxoma with emphasis on CT and MR and comparison of radiologic and pathologic findings

PURPOSE: To determine the imaging characteristics of soft-tissue myxoma, with emphasis on computed tomographic (CT) and magnetic resonance (MR) imaging findings and pathologic comparison. MATERIALS AND METHODS: Records of 45 pathologically confirmed soft-tissue myxomas in 44 patients were retrospectively reviewed. Patient demographics and radiographs (n = 20), bone scintigrams (n = 2), angiograms (n = 3), and ultrasonographic (US) (n = 6), CT (n = 14), and MR images (n = 33) were evaluated by two musculoskeletal radiologists with agreement by consensus for lesion location, lesion size, and intrinsic characteristics. RESULTS: Soft-tissue myxoma more commonly affected women (59%; average age 52 years) and manifested as a slowly enlarging (64%) painful (51%) mass. Lesions were most frequently intramuscular (82%) and involved the thigh (51%). An appearance similar to that of a cyst was seen at CT (at which the lesions demonstrated low attenuation) and at MR imaging (at which the lesions demonstrated markedly high signal intensity on T2-weighted images) in all cases because of the high water content of mucin that was seen histologically. The true solid architecture of these lesions was best depicted in all cases at US (at which the lesions were hypoechoic, not anechoic) and on MR images obtained with contrast material (at which the lesions demonstrated internal enhancement). A small amount of tissue similar to fat surrounding these intramuscular myxomas (71% at MR imaging) corresponded histologically (70%) to atrophy of surrounding muscle. CONCLUSION: Soft-tissue myxoma often demonstrates characteristic US, CT, and MR imaging findings, including intramuscular location, intrinsic high water content, and a surrounding rim of fat.     

血管扩张型骨肉瘤的临床、影像和病理分析

目的 进一步分析血管扩张型骨肉瘤的临床、影像及病理学的诊断特征和诊断方法,以加深对其认识和提高诊断水平.方法 回顾性分析10例经病理证实的血管扩张型骨肉瘤资料并结合文献深入分析其临床、影像和病理学表现.10例均行X线平片和MR检查,其中2例同时行CT检查.结果 10例血管扩张型骨肉瘤发生于股骨下端5例、股骨颈1例、肱骨上端和胫骨上段各2例.10例X线平片和2例CT 图像上肿瘤表现为溶骨性骨质破坏,伴骨体轻度膨胀4例,骨破坏区大部分边缘不清且无硬化边,均有Codman三角和大小不一的软组织肿块,肿块内无明显肿瘤性成骨;10例MRI上肿瘤大部或完全由多发囊腔构成,均出现骨膜反应,其中7例囊腔内见少量散在的较小液-液平面.10例病理学上肿瘤均有类似动脉瘤样骨囊肿的血腔结构,但囊壁或囊间隔中见恶性肿瘤细胞以及数量不一的肿瘤性成骨组织,其中6例仅见少量灶状的肿瘤性骨样组织.结论 影像学上类似动脉瘤样骨囊肿的表现和一般恶性骨肿瘤生长方式的特点,以及病理上的血腔结构和囊壁或囊间隔内的恶性肿瘤细胞是血管扩张型骨肉瘤的影像和病理学诊断特征.密切结合临床、影像和病理分析有助于临床及时正确诊断.     

Imaging of periosteal osteosarcoma: radiologic-pathologic comparison

PURPOSE: To review the imaging appearance of periosteal osteosarcoma, with pathologic comparison. MATERIALS AND METHODS: Data for 40 pathologically confirmed periosteal osteosarcomas were retrospectively reviewed. Patient demographic data were recorded, and radiographs (n = 40), bone scintigrams (n = 10), angiograms (n = 2), and computed tomographic (CT) (n = 11) and magnetic resonance (MR) (n = 12) images were evaluated for lesion location and size, cortical changes, marrow involvement, and intrinsic characteristics by two musculoskeletal radiologists, with agreement by consensus. Pathology reports were reviewed for presence and predominance of histologic components (fibrous, chondroid, and osteoid), tumor grade, and marrow involvement. RESULTS: There were 25 male (62%) and 15 female (38%) patients with an age range of 10-37 years (average age, 20 years). The most frequent lesion locations were the diaphysis of the tibia (16 patients) or of the femur (15 patients). Radiographs showed a broad-based soft-tissue mass that was attached to the cortex (all patients) and showed cortical thickening (33 patients), cortical scalloping/erosion (37 patients), and/or perpendicular periosteal reaction (38 patients) extending into the soft-tissue mass. Soft-tissue masses were well defined in 91%-100% of cases and surrounded a median of 50%-55% of the cortex. Lesions commonly showed low attenuation at CT (10 patients) and high signal intensity on T2-weighted MR images (10 patients), reflecting the high water content of these largely chondroblastic lesions. Focal areas of adjacent marrow replacement were common at MR imaging (nine patients) but represented reactive changes unless they were in direct continuity with the overlying soft-tissue mass (this was rare, occurring in only one patient, and represented marrow invasion). Review of pathology reports revealed that all lesions contained chondroid tissue, which predominated in 34 patients. CONCLUSION: The radiologic appearance of periosteal osteosarcoma is a broad-based surface soft-tissue mass causing extrinsic erosion of thickened underlying diaphyseal cortex and perpendicular periosteal reaction extending into the soft-tissue component. Reactive marrow changes are commonly seen at MR imaging, but true marrow invasion is rare.     

Intramedullary osteosclerosis: imaging features in nine patients.

PURPOSE: To determine the conventional radiographic, computed tomographic (CT), magnetic resonance (MR) imaging, scintigraphic, and histologic features of intramedullary osteosclerosis and to review the clinical features. MATERIALS AND METHODS: Nine female patients with leg pain and imaging features indicative of intramedullary sclerosis were seen during a 25-year period. None of the patients had a history of trauma or infection, familial bone disease, or related abnormal laboratory findings. Imaging studies included radiography (n = 9), CT (n = 4), MR imaging (n = 5), and skeletal scintigraphy (n = 5). Histologic correlation was available in five patients. RESULTS: Sixteen bone lesions (midtibia, n = 14; distal fibula, n = 1; and proximal femur, n = 1) were evident. Both lower extremities were involved in seven patients, and a single extremity was involved in two. Intramedullary sclerosis was present, as was cortical thickening, mainly in the diaphysis of the long bones, without extensive periosteal reaction or soft-tissue involvement. Findings at bone scintigraphy were positive in all lesions. Histologic analysis showed nonspecific changes of markedly sclerotic bone with a variable degree of mineralization and maturity. CONCLUSION: Intramedullary osteosclerosis is a distinct disorder that typically affects the diaphysis of one or both tibiae in women. Characteristic imaging findings, when coupled with clinical information, allow precise diagnosis.     

血管扩张型骨肉瘤的临床、影像和病理分析

目的 进一步分析血管扩张型骨肉瘤的临床、影像及病理学的诊断特征和诊断方法,以加深对其认识和提高诊断水平.方法 回顾性分析10例经病理证实的血管扩张型骨肉瘤资料并结合文献深入分析其临床、影像和病理学表现.10例均行X线平片和MR检查,其中2例同时行CT检查.结果 10例血管扩张型骨肉瘤发生于股骨下端5例、股骨颈1例、肱骨上端和胫骨上段各2例.10例X线平片和2例CT 图像上肿瘤表现为溶骨性骨质破坏,伴骨体轻度膨胀4例,骨破坏区大部分边缘不清且无硬化边,均有Codman三角和大小不一的软组织肿块,肿块内无明显肿瘤性成骨;10例MRI上肿瘤大部或完全由多发囊腔构成,均出现骨膜反应,其中7例囊腔内见少量散在的较小液-液平面.10例病理学上肿瘤均有类似动脉瘤样骨囊肿的血腔结构,但囊壁或囊间隔中见恶性肿瘤细胞以及数量不一的肿瘤性成骨组织,其中6例仅见少量灶状的肿瘤性骨样组织.结论 影像学上类似动脉瘤样骨囊肿的表现和一般恶性骨肿瘤生长方式的特点,以及病理上的血腔结构和囊壁或囊间隔内的恶性肿瘤细胞是血管扩张型骨肉瘤的影像和病理学诊断特征.密切结合临床、影像和病理分析有助于临床及时正确诊断.     

Craniofacial osteosarcomas: plain film, CT, and MR findings in 46 cases

Forty-six osteosarcomas of the cranial and facial bones were reviewed radiographically by using the conventional parameters for long bone tumors. There were 32 de novo osteosarcomas (11 maxillary, 13 mandibular, and eight cranial) and 14 postradiation osteosarcomas. All the maxillary tumors originated from the alveolar ridge, and the majority of mandibular lesions began in the body of the mandible. The postradiation osteosarcomas occurred in portions of bones at the borders of the radiation field; the latent period ranged from 4 years, 2 months to 50 years (mean, 14 years). The majority of de novo or postradiation craniofacial osteosarcomas were osteolytic with a long transition zone and no periosteal reaction; the exception was in the mandible, where nearly half the cases were osteoblastic and periosteal reaction was occasionally present. Tumor matrix mineralization occurred in more than 75% of the cases, and osteoid matrix calcification was most frequent, even though most tumors were chondroblastic. Soft-tissue extension of tumor was present in all cases and contained calcifications in more than half. Conventional radiographs are of limited value in evaluating head and neck osteosarcomas because of the superimposed bony structures. CT provides excellent detection of tumor calcification, cortical involvement, and, in most instances, soft-tissue and intramedullary extension. MR is even more effective in demonstrating the intramedullary and extraosseous tumor components on both T1- and T2-weighted images. However, CT and plain films are superior to MR in detecting the matrix calcifications and bone destruction or reaction.     

Aneurysmal bone cyst of the orbit

Aneurysmal bone cysts of the skull are rare, and orbital involvement of these cysts is even less frequent. We present CT, MR imaging, and histopathologic findings of an aneurysmal bone cyst of the orbit in a 13-year-old female adolescent. The tumor mainly involved the frontal bone. MR imaging findings of the aneurysmal bone cyst of the skull were highly suggestive of the diagnosis.     

Imaging features of primary lymphoma of bone

OBJECTIVE: Our objective was to describe the imaging appearances of primary lymphoma of bone, including conventional radiographic, scintigraphic, CT, and MR imaging features. MATERIALS AND METHODS: We retrospectively reviewed 237 pathologically proven cases of primary lymphoma of bone. Evaluation included patient age, sex, lesion location, and pattern of bone destruction. Pathologic type, periosteal reaction, sequestrum, soft-tissue mass, extension across joints, and pathologic fracture were also noted. RESULTS: The study population included 151 males and 86 females (ratio 1.8:1; range, 2-88 years; mean age, 42 years). Common locations were the distal femoral diametaphysis; proximal metadiaphysis of the tibia, femur, and humerus; and femoral mid shaft. Long bones were involved more often than flat bones (71% versus 22%). Common appearances were a lytic (70%) or mixed-density (28%) lesion with most cases showing a permeative or moth-eaten pattern (74%). Periosteal reaction was seen in 58% of the long bones. Sequestra were found in 37 patients (16%). Soft-tissue masses were present in 113 patients (48%). Extension across joints was seen in nine patients (4%). Pathologic fractures occurred in 53 patients (22%). Radionuclide (n = 56), CT (n = 45), and MR (n = 20) features were usually nonspecific. Pathologic types included non-Hodgkin's (n = 223) and Hodgkin's (n = 14) lymphoma. CONCLUSION: Primary lymphoma of bone most often involves the diametaphysis of a major long bone and has an aggressive pattern of lytic bone destruction and associated soft-tissue mass. CT and MR imaging can suggest the diagnosis, particularly when a large soft-tissue mass and abnormal marrow attenuation or signal intensity is seen without extensive cortical destruction.     

Imaging of chest wall disorders.

Pathologic processes that may involve the chest wall include congenital and developmental anomalies, inflammatory and infectious diseases, and soft-tissue and bone tumors. Many of these processes have characteristic radiologic appearances that allow definitive diagnosis. Sternal deformities can be visualized at radiography and their severity quantified with computed tomography (CT). In cervical rib, CT with multiplanar reconstruction may demonstrate relevant anatomic detail and the relationship between bone deformity and arterial compression. In Poland syndrome, radiography reveals an area of hyperlucency on the affected side, whereas CT demonstrates the absence of the greater pectoral muscle and clearly depicts associated musculoskeletal anomalies. Tuberculosis typically manifests at radiography and CT as osseous and cartilaginous destruction and soft-tissue masses with calcification and rim enhancement. Aspergillosis involving the chest wall manifests as pulmonary consolidations and permeative osteolytic changes of the rib and spine at CT and as an area of increased signal intensity at T2-weighted magnetic resonance (MR) imaging. Neurogenic tumors and hemangiomas also typically have high signal intensity at T2-weighted MR imaging. Apparent mass extension or unequivocal bone destruction seen at CT or MR imaging may indicate chest wall involvement by lymphoma. Radiologically, soft-tissue sarcomas typically appear as areas of soft-tissue density or attenuation, often associated with necrotic areas of low density or attenuation. At radiography, plasmacytoma typically manifests as well-defined, "punched-out" lytic lesions with associated extrapleural soft-tissue masses. Chondrosarcoma frequently appears as a large, lobulated excrescent mass arising from a rib with scattered flocculent calcifications characteristic of its cartilaginous mix. Familiarity with these radiologic features facilitates accurate diagnosis and optimal patient treatment.     

Fluid-fluid levels in bone and soft tissue tumors demonstrated by MR imaging]

Fluid-fluid levels in bone tumors have been described in aneurysmal bone cysts and other cystic tumors of bones and soft tissue tumors. We experienced three bone tumors (simple bone cyst, bone metastasis, and osteosarcoma) and three soft tissue tumors (fibrosarcoma, two cases of cavernous hemangioma) that showed fluid-fluid levels on MR, and investigated their cause. Causes included blood in the cystic spaces, hemorrhage in the tumor, the telangiectatic component of the osteosarcoma, and the cavernous component of the hemangioma. No specific diagnosis could be made based on the finding of fluid-fluid levels. We conclude that fluid-fluid levels on MR are rather nonspecific findings in bone and soft tissue tumors and that the diagnosis should be made on the basis of other radiological and clinical findings.     

Imaging findings in pseudocystic osteosarcoma

OBJECTIVE: Our purpose was to describe four female patients with osteosarcoma whose clinical and imaging findings primarily suggested either simple or aneurysmal bone cyst. All lesions were osteolytic, intracompartmental, and expanded bone without periosteal reaction. None of the patients presented during the peak age incidence for osteosarcoma. From imaging to histologic diagnosis, the discovery of osteosarcoma ranged from 1 week to 3 years. CONCLUSION: Atypical osteosarcoma may rarely mimic simple or aneurysmal bone cyst radiologically and may show a nonmalignant rate of growth. It may be more frequently encountered in females and may not present during the peak age incidence for osteosarcoma. Microscopically, the tumors were not cystic, necrotic, or telangiectatic but were conventional osteosarcoma and osteoclast-rich osteosarcoma.     

Imaging features of subperiosteal aneurysmal bone cyst

PURPOSE: To analyze the imaging features of subperiosteal aneurysmal bone cyst. MATERIAL AND METHODS: The imaging material of 6 patients with biopsy-proved subperiosteal aneurysmal bone cyst was reviewed. Evaluation included patient demographics, lesion location and size, radiographic features, and intrinsic characteristics on CT and MR images. Review of histologic specimens was carried out by an experienced musculoskeletal pathologist. RESULTS: All lesions were located at the surface of long tubular bones (femur 3, tibia 2, humerus 1): 3 involved the diaphysis, 2 the dia/metaphysis, and 1 exclusively the metaphysis. Lesion size ranged from 2.5 to 6 cm in maximum diameter. Radiographs and CT images always showed a superficial bone defect, which on radiographs demonstrated irregular margins in 4 cases. All lesions caused an interrupted periosteal reaction (shell 3, trabeculated shell 1, Codman angle 2). MR images always showed a multicystic appearance with a hypointense rim, contrast-enhancing cyst walls, and fluid levels. Edema of adjacent soft tissues was present in all cases. CONCLUSION: Aneurysmal bone cyst in a subperiosteal location can demonstrate an aggressive radiographic appearance. MR imaging appears to be most valuable in the differential diagnosis, since it can demonstrate typical morphological features of the underlying process.     

Mycetoma: comparison of MR imaging with CT

Magnetic resonance (MR) images obtained in 18 patients with pathologically confirmed mycetoma in the body (n = 4) or lower extremity (n = 14) were retrospectively reviewed and compared with computed tomographic (CT) scans in 15 patients and surgical findings in 10. T1-weighted images showed an infiltrating mass (same signal intensity as muscle) involving skin, subcutaneous fat, muscles, tendons, and other tissues. On T2-weighted images, the mass and affected structures showed moderately increased signal intensity. Bone marrow involvement was detected in seven patients and was best visualized on T1-weighted images. CT showed moderate enhancement of the infiltrative process in all patients. Bone changes, seen in nine, included coarse trabeculation, periosteal reaction, endosteal proliferation, and patchy destruction. MR imaging and CT were comparable and correlated well with surgery in showing the extent of soft-tissue involvement. Early bone changes (important for therapy planning for pedal mycetoma) were seen only at CT. The study showed that MR imaging is sensitive for assessing the extent of mycetoma in the soft tissues. CT should be the method of choice for staging pedal lesions because it can be used to detect early bone involvement.     

From the archives of AFIP. Imaging of giant cell tumor and giant cell reparative granuloma of bone: radiologic-pathologic correlation.

The radiologic features of giant cell tumor (GCT) and giant cell reparative granuloma (GCRG) of bone often strongly suggest the diagnosis and reflect their pathologic appearance. At radiography, GCT often demonstrates a metaepiphyseal location with extension to subchondral bone. GCRG has a similar appearance but most commonly affects the mandible, maxilla, hands, or feet. Computed tomography and magnetic resonance (MR) imaging are helpful in staging lesions, particularly in delineating soft-tissue extension. Cystic (secondary aneurysmal bone cyst) components are reported in 14% of GCTs. However, biopsy must be directed at the solid regions, which harbor diagnostic tissue. These solid components demonstrate low to intermediate signal intensity at T2-weighted MR imaging, a feature that can be helpful in diagnosis. Multiple GCTs, although rare, do occur and may be associated with Paget disease. Malignant GCT accounts for 5%-10% of all GCTs and is usually secondary to previous irradiation of benign GCT. Treatment of GCT usually consists of surgical resection. Recurrence is seen in 2%-25% of cases, and imaging is vital for early detection. Recognition of the spectrum of radiologic appearances of GCT and GCRG is important in allowing prospective diagnosis, guiding therapy, and facilitating early detection of recurrence.