Aneurysmal bone cyst. A review of 123 cases including primary lesions and those secondary to other bone pathology

A group of 639 bone lesions was reviewed in order to study the features of the aneurysmal bone cyst and its association with other conditions. A diagnosis of primary aneurysmal bone cyst not associated with any other bone lesion was made in 87 patients. In 36 additional patients the gross and microscopic changes of aneurysmal bone cyst were identified as part of some other solid bone lesion. Fourteen of these additional cases were associated with giant cell tumor (96 cases studied), six with chondroblastoma (41 cases studied), three with chondromyxoid fibroma (45 cases studied), two with nonossifying fibroma (68 cases studied), four with osteoblastoma (61 cases studied), one with fibrosarcoma (50 cases studied), three with fibrous histiocytoma (45 cases studied), two with osteosarcoma (100 cases studied), and one with fibrous dysplasia (42 cases studied). The age, site, and sex distribution of the cases associated with another lesion compares closely with that of the solid lesion concerned, supporting the concept that the aneurysmal bone cyst component is secondary.

Magnetic resonance imaging of cartilaginous tumors: a retrospective study of 79 patients

OBJECTIVE

Hyaline cartilaginous tumors are characterized by extremely high signal intensity on T2-weighted images. Recently, some distinctive MR features of cartilaginous bone tumors were reported in small series. Low signal intensity septa surrounding high signal intensity cartilage lobules were seen on T2-weighted images in low-grade chondrosarcomas. On spin-echo T1-weighted images after Gd contrast injection, marked 'septal' or 'ring-and-arc' enhancement was observed in low-grade chondrosarcomas and enchondromas. The purpose of this study was to determine sensitivity and specificity of these MR findings in diagnosis of cartilaginous tumors, and to assess the value of MR in diagnostic workup of these lesions.

MATERIALS AND METHODS

Retrospective evaluation of MR findings in 79 cartilaginous tumors and in 79 non-cartilaginous tumors. All lesions were biopsy proven. Each MR examination was independently reviewed by two experienced radiologists without knowledge of clinical data, radiographic and/or CT findings, or histological diagnosis. All lesions were evaluated for morphology (lobular or non-lobular), presence of a high signal intensity mass on T2-weighted images, presence of low signal intensity septa separating high signal intensity lobules on T2-weighted images, and evidence of septal ('ring-and-arc') enhancement.

RESULTS

None of the reviewed parameters is useful in diagnosing osteochondromas. Since osteochondromas have a characteristic appearance on plain radiography, the value of MR imaging in the workup of these lesions remains limited. MR findings in enchondromas have a low specificity and a low sensitivity. Low-grade chondrosarcomas, often hard to diagnose on plain radiography and difficult to differentiate from enchondromas, are characterized by the MR tandem of 'low signal intensity septa on T2-weighted images' together with 'septal or ring-and-arc enhancement' (sensitivity 92.3%, specificity 76.5%). High-grade chondrosarcomas are easily recognized on plain radiography.

CONCLUSIONS

In differentiating cartilaginous from non-cartilaginous tumors, MR features are highly specific but lack sensitivity. Grading potentials of MR parameters are promising due to the high accuracy in diagnosing low-grade chondrosarcomas.

Chondromyxoid fibroma of the skull base: a tumor which may be confused with chordoma and chondrosarcoma. A report of three cases and review of the literature

Three cases of chondromyxoid fibroma arising in the skull base are reported. The tumors arose in females 34, 65, and 66 (median 55) years of age. Two women presented with headaches, and one with nasal obstruction. Radiographic studies revealed that all three lesions were expansile soft tissue masses centered in the clivus, at least 4 cm in greatest diameter. One lesion involved primarily the clivus, the others extended from the clivus into the sphenoid and ethmoid sinuses. Two of the three cases were initially misdiagnosed as chordoma or chondrosarcoma. The initial treatment was curettage of gross disease in all three cases. One patient also received radiation therapy. One patient had local progression of disease, which was treated with surgery and radiation therapy. All patients are clinically free of disease 11 to 26 months following the most recent treatment. Chondromyxoid fibroma can and should be distinguished from chondrosarcoma and chordoma, two tumors which more commonly arise in the skull base and which have the potential to metastasize.

Chondroblastoma and clear cell chondrosarcoma: radiological and MRI characteristics with histopathological correlation

OBJECTIVE

To analyze and compare the radiological and magnetic resonance imaging (MRI) appearances of chondroblastoma and clear cell chondrosarcoma with histopathological correlation.

DESIGN AND PATIENTS

Twelve patients with histologically proven chondroblastoma and of another four patients with clear cell chondrosarcoma were investigated by radiographs and MRI (T1-, T2-weighted sequences, intravenous gadolinium application). Additionally, the clinical and radiologic data of seven cases of clear cell chondrosarcoma without available MRI were considered. The localization, calcification of tumor matrix, periosteal reaction, cortical bone and patterns of bone destruction were analyzed according to the Lodwick radiological grading system (LRGS). The signal intensity on T1- and T2-weighted sequences, characteristics of contrast enhancement, associated bone marrow edema, soft tissue reaction and joint involvement were evaluated. Histopathological specimens were available in all cases.

RESULTS

The age of patients with chondroblastoma (range 15-59 years, mean 22.3 years) was lower than that of those with clear cell chondrosarcoma (range 19-61 years, mean 36.6 years), and the lesions were smaller in the chondroblastoma group (range 1-4 cm, mean 2.3 cm) than in patients with clear cell chondrosarcoma (range 3-7.5 cm, mean 5.2 cm). The chondroblastomas were more confined to the epiphysis (10/12) than the clear cell chondrosarcomas. All chondroblastomas and clear cell chondrosarcomas except one were classified as grade 1A or 1B according to the LRGS; one clear cell chondrosarcoma was judged as grade 2. Signal intensity of the tumors on MRI was very heterogeneous in both groups. High signal intensity on T2-weighted MR images in chondroblastoma mostly corresponded to areas with aneurysmal bone cyst components and in clear cell chondrosarcoma to islands of hyaline cartilage. Contrast enhancement occurred in all tumors and tended to be more intense with clear cell chondrosarcoma. Chondroblastoma was more frequently associated with bone marrow edema (11/12), periosteal reaction (10/12), soft tissue reaction (7/12) and synovitis (3/12).

CONCLUSION

Chondroblastoma occurs in younger patients, is smaller than clear cell chondrosarcoma and is more confined to the epiphysis. The overlap of signal intensity and contrast enhancement patterns does not allow a reliable differentiation of the two tumors by MRI. Chondroblastomas are typically associated with bone marrow edema, periosteal reaction and soft tissue reaction.

S-100 protein immunostaining in the differential diagnosis of chondroblastoma

In an effort to investigate the utility of immunostaining for S-100 protein in the differential diagnosis of chondroblastoma, the expression of S-100 protein in nine chondroblastomas was compared with that in six giant cell tumors, six aneurysmal bone cysts, four giant cell reparative granulomas, six cases of fibrous dysplasia, two cases of osteitis fibrosa cystica, two nonossifying fibromas, and one clear cell chondrosarcoma. Five enchondromas, three typical chondrosarcomas, and one mesenchymal chondrosarcoma were also included as control tumors. The proliferating stromal cells in seven of the nine chondroblastomas stained for S-100 protein, as did the lacunar chondrocytes in all of the enchondromas and chondrosarcomas and rare stromal cells in the clear cell chondrosarcoma. In contrast, none of the other tumefactive bone lesions included in this study demonstrated S-100 protein immunoreactivity. These results suggest that immunohistochemical assessment of S-100 protein may be a method for diagnostically separating chondroblastoma from pathologic entities that could be histologically confused with it in the presence of limited biopsy material. However, clear cell chondrosarcoma would appear to represent an exception to this general statement.

Chondroblastoma: classic and confusing appearance at MR imaging

PURPOSE

To define the characteristics of chondroblastoma at magnetic resonance (MR) imaging and the combination of findings that are diagnostic for chondroblastoma.

MATERIALS AND METHODS

From January 1987 through December 1992, 22 patients with histologically confirmed chondroblastoma and prior MR imaging examinations were seen. Patients included 16 men and six women, aged 10-58 years (median, 17 years). Retrospective analysis of findings at MR imaging, plain radiography, computed tomography, and bone scanning was performed.

RESULTS

Low to intermediate heterogeneous signal intensity, lobular internal architecture, and fine lobular margins were well defined with high-resolution T2-weighted (repetition time > or = 1,500 msec, echo time > or = 70 msec) MR imaging. Adjacent bone-marrow and soft-tissue edema and periosteal reactions were more dramatically demonstrated on MR images than on radiographs. Bone marrow edema was prominent in all but five cases. Obvious periosteal reaction and adjacent soft-tissue edema were visible in 17 cases.

CONCLUSION

Knowledge of the MR imaging findings of chondroblastoma will allow accurate diagnosis and help avoid confusion with infection and aggressive neoplasms.

Misleading aggressive MR imaging appearance of some benign musculoskeletal lesions

After plain radiography has been performed, magnetic resonance (MR) imaging is considered the modality of choice for the evaluation of suspected musculoskeletal lesions because of its exquisite sensitivity to changes in the signal intensity of marrow and soft tissue. That sensitivity, however, may lead to an overestimation of the aggressiveness and extent of some benign bone lesions, particularly in children. Such lesions include chondroblastoma, osteoid osteoma, eosinophilic granuloma, and stress fractures. Potentially misleading MR features commonly seen include prominent marrow edema, soft-tissue edema, and apparent mass effect adjacent to the bone lesion. Features that these lesions have in common that may explain the MR findings include associated inflammatory reactions caused by the lesions and their occurrence in childhood, when the periosteum is more loosely attached. Knowledge of the potential pitfalls encountered with MR imaging may help explain the discrepancy between the radiographic and MR appearances of these benign lesions and avoid misplaced reliance on MR imaging for a diagnosis. Radiography remains the single most valuable modality in determining a differential diagnosis for bone lesions.

Malignant transformation of fibrous dysplasia into chondroblastic osteosarcoma

A case of malignant transformation of polyostotic fibrous dysplasia into maxillary chondroblastic osteosarcoma is presented. The clinical, radiographic, CT, MR imaging features and pathological findings of polyostotic fibrous dysplasia and its malignant transformation are described. Malignant transformation of fibrous dysplasia is rare and has not previously been described in the English literature in this location in McCune-Albright syndrome and in the absence of radiation treatment.

Chondroblastoma of the hands and feet

OBJECTIVE

To review the imaging findings, age and gender distribution of chondroblastoma of the hands and feet.

DESIGN AND PATIENTS

Twenty-five cases of pathologically proven chondroblastoma of the hands and feet were reviewed. Available imaging modalities included radiographs (n=24), CT (n=3), MRI (n=5), and radionuclide bone scintigraphy (n=1). The following imaging features for each case were tabulated: location, presence of sclerotic margin, calcification, expansion, presence of fluid/fluid levels on cross-sectional imaging and surrounding edema on MRI. The images were evaluated for skeletal maturity using closure of the physeal plate in the region as a standard.

RESULTS

The average age at time of diagnosis was 23 years (range 7-57 years). Eighty-four percent (n=21) of the patients were skeletally mature. Males (20 of 25) outnumbered females by a ratio of 5:1. The bones of the foot accounted for 22 cases: calcaneus (n=8), talus (n=8), metatarsals (n=3), and the cuboid (n=3). The bones of the hand accounted for three cases: phalanx (n=1), triquetrum (n=1), and a metacarpal (n=1). Radiographically all lesions were osteolytic with identifiable calcification in 54% (13 of 24). Fluid/fluid levels were seen in four of five cases on MRI. Edema on MR images was seen in 40% (2 of 5). The size of the lesions ranged from 2 to 41 cm(2).

CONCLUSION

Chondroblastomas of the hands and feet share many of the radiographic characteristics seen in the long bones, but manifest in skeletally mature patients with a higher male to female ratio than in long bone chondroblastoma. Talar and calcaneal lesions were encountered only in males. Chondroblastoma of the wrist and hand appears to be exceptionally rare.

Chondroblastoma: MR characteristics with pathologic correlation

PURPOSE

The purpose of this study was to describe the MR findings of chondroblastoma with pathologic correlation.

METHOD

In 22 patients with pathologically proven chondroblastoma, MR signal characteristics were correlated with pathological findings.

RESULTS

On T2-weighted images, 12 (55%) lesions were hyperintense with hypointense areas in 9 lesions, whereas 10 (45%) were hypointense. Therefore, 19 of 22 (86%) lesions with pathologic correlation had hypointense areas entirely (n = 10) or partly (n = 9) on T2-weighted images. On gadolinium-enhanced images, 13 (59%) lesions showed lobular enhancement and 9 (41%) showed marginal and septal enhancement. Low signal intensity on T2-weighted MR images was most strongly associated with an abundance of immature chondroid matrix, hypercellularity of the chondroblasts, calcifications, and hemosiderin on histology.

CONCLUSION

Chondroblastoma was found to show hypointense portions on T2-weighted images. Signal intensity on T1- and T2-weighted MR images in chondroblastoma was dependent on the amounts of histopathological components.

Benign chondroid neoplasms of bone

Benign cartilage lesions discussed in this article include osteochondroma (solitary, epiphyseal, and multiple), chondroblastoma, periosteal chondroma, and chondromyxoid fibroma. These lesions often demonstrate imaging appearances strongly suggesting the above diagnosis, particularly the "ring and arc" mineralization characteristic of cartilage lesions, which reflects their underlying pathology. This article emphasizes the imaging spectrum of these lesions with a multimodality approach.

Extremity bone tumors: evaluation by P-31 MR spectroscopy

High-resolution P-31 MR spectra were obtained in four patients with bone tumors of their distal extremities. In one case the tumor, a Ewing sarcoma of the tibia, was investigated during clinical remission after radiation therapy and chemotherapy. The other three cases - one low-grade chondrosarcoma of the tibial head, one malignant fibrous histiocytoma of the tibia, and one chondroblastoma of the medial femoral condyle - showed clinically active tumor growth, with corresponding increased metabolism as demonstrated by bone scintigraphy. The spectra of the three active tumors indicated a comparably high adenosine triphosphate content, similar to previously published spectra from animal tumors or human tumors implanted into animals. There were also high resonances of inorganic phosphate and low resonances of phosphocreatine; there were definite peaks in the phosphodiester and phosphomonoester regions, indicating the existence of these metabolites in the tumors. Slight but definite changes in the metabolite content were observed in one tumor after chemotherapy. The spectra of the unaffected leg did not show any well-resolved P-31 signals, which is typical for healthy bone. These are the first P-31 MR spectra of human bone tumors measured in patients to our knowledge.

Vertebral chondroblastoma

OBJECTIVE

To determine the age distribution, gender, incidence, and imaging findings of vertebral chondroblastoma, and to compare our series with findings from case reports in the world literature.

DESIGN AND PATIENTS

Case records and imaging findings of nine histologically documented vertebral chondroblastomas were retrospectively reviewed for patient age, gender, vertebral column location and level, morphology, matrix, edema, soft tissue mass, spinal canal invasion, and metastases. Our findings were compared with a total of nine patients identified from previous publications in the world literature. The histologic findings in our cases was re-reviewed for diagnosis and specifically for features of calcification and secondary aneurysmal bone cyst (ABC). Clinical follow-up was requested from referring institutions.

RESULTS

Nine of 856 chondroblastomas arose in vertebrae (incidence 1.4%; thoracic 5, lumbar 1, cervical 2, sacral 1). There were six males and three females ranging in age from 5 to 41 years (mean 28 years). Satisfactory imaging from seven patients revealed the tumor to arise from the posterior elements in four and the body in three. All tumors were expansive, six of seven were aggressive, and the spinal canal was significantly narrowed by bone or soft tissue mass in six. In one patient canal invasion was minimal. Calcification was pronounced in two and subtle in four. The sole nonaggressive-appearing tumor was heavily mineralized. Bony edema and secondary ABC were not seen on MR imaging. None of the cases had microscopic features of significant secondary ABC. Calcification, and specifically "chicken wire" calcification, was identified in two patients. Pulmonary metastases occurred in none.

CONCLUSIONS

Vertebral chondroblastoma is a rare neoplasm that presents later in life than its appendicular counterpart. On imaging it is aggressive in appearance with bone destruction, soft tissue mass, and spinal canal invasion. The lesions contain variable amounts of mineral. Secondary aneurysmal cyst bone formation was not a feature in our study group.

Chondroblastoma during the growing age

Chondroblastoma is a benign tumor of bone with a relatively high incidence in older children and adolescents. The regions of the shoulder, hip, and knee are mainly affected, with preference for the epiphysis. Treatment currently consists of excochleation, bone grafts, and sometimes adjuvant therapy such as phenol cauterization or cryosurgery. Because the tumor often is localized near a joint or growth plate, functional impairment and growth disturbances could be expected. Recurrences also are a major concern. A brief overview is given, as well as a presentation of 116 cases in the growing age group from the material of the Dutch Bone Tumor Committee. It seems justified to conclude that most lesions will heal with proper excochleation and bone graft, but there is a reasonable chance of recurrence. Loss of function as well as growth disturbances were not commonly seen in our series. One case of metastasis was found.

Giant cell reparative granuloma and other giant cell lesions of the bones of the hands and feet

The present paper is a clinico-pathologic study of 52 osteolytic lesions containing giant cells, affecting the hands and feet and comprising 11 giant cell reparative granulomas, nine giant cell tumors, six chondroblastomas, and 26 aneurysmal bone cysts. The nature of osteolytic lesions of hands and feet must be carefully established in order to plan appropriate treatment without damaging the surrounding structures. Giant cell reparative granuloma has to be distinguished from other lesions containing giant cells. Clinical and radiologic findings proved of limited diagnostic value; the definitive diagnosis can be established only by histologic examination. Surgical treatment is discussed.

Inflammatory reaction in chondroblastoma

OBJECTIVE

The objective of this study was to evaluate the inflammatory reaction accompanying chondroblastoma and to define the value of the finding in clinical practice.

DESIGN

We reviewed the clinical, radiographic, and magnetic resonance (MR) findings in six patients with histologically proven chondroblastoma.

RESULTS

In all cases, MR imaging showed marrow and soft tissue edema. In four of six cases, periosteal reaction related to intra-osseous edema was more clearly demonstrated on MR imaging than on radiographs. Follow-up MR studies after surgery were available in three patients and all showed disappearance of inflammatory responses such as marrow and soft tissue edema, and reactive synovitis.

CONCLUSION

We propose that these inflammatory reactions of chondroblastomas are important signs for detecting residual tumor in recurrences after surgery, as well as for making a precise diagnosis. The MR changes may also be valuable in demonstrating eradication of the tumor.

Cytophotometric studies of the nuclear DNA content in cartilaginous tumors

The histopathological differentiation between chondromas and low-grade malignant chondrosarcomas can be difficult. For this reason we studied in 37 different cartilaginous tumors the mitotic index and the Feulgen DNA content using a scanning-integration cytophotometric technique. In 23 chondromas the Feulgen DNA content was diploid and showed a unimodal normal distribution. The number of mitoses was 0--0, 5%. The nuclei of a chondroblastoma were also diploid and the Feulgen DNA content was normally distributed. The mitotic index was 1% and few tetraploid nuclei, which were probably G2 nuclei, were observed. In two chondromyxoid fibromas, the average Feulgen DNA content was diploid and normally distributed. Several tetraploid nuclei were noted. The mitotic index was respectively 0.25% and 1.75%. Recurrence was noted in the first case. The Feulgen DNA content and mitotic index were clearly different in the chondrosarcomas. The distribution of the DNA content was bimodal or unimodal in low-grade chondrosarcomas. The mitotic index was less than 3%. In high-grade malignant chondrosarcomas, the histograms were broad unimodal or aneuploid. The mitotic index was above 5%.

Chondroblastoma of the temporal bone. Case report and literature review

Chondroblastoma is a rare tumor of bone that represents approximately 1% of all primary bone tumors. In the temporal bone, only 33 have been reported. We present a case of chondroblastoma of the temporal bone, followed by a literature review and analysis of reported cases. We conclude that the best chance for a prolonged disease-free interval is total excision using a combined otolaryngologic and neurosurgical approach.

Benign chondroblastoma of the temporal bone

Benign chondroblastoma is a rare tumor in the temporal bone. It occurs preponderantly in middle-aged men as a mass in the postero-superior region of the ear canal and is accompanied by hearing loss. On pathologic examination, giant cells and focal regions of chondroid differentiation are noted. After the extent of the tumor has been determined, the treatment is surgical removal. Preoperative irradiation may be helpful. Long-term follow-up is essential.

Chondroblastoma of the temporal bone: a clinicopathologic study of five cases

Chondroblastoma is a rare benign bone tumor. It commonly affects the epiphysis of long bones during the second and third decades of life. Chondroblastoma of the temporal bone is extremely rare. We reviewed five cases of chondroblastoma arising in the temporal bone. Four cases were female and one was male. The ages ranged from 41 to 60 years (mean, 53.6 years). All cases involved the temporal bone. Three involved the left side and two the right. Chief complaints were long-standing localized pain and hearing difficulty. A sharply demarcated lobulated mass was the main radiological finding. Microscopic findings were those of chondroblastoma of usual locations. Two cases showed aneurysmal bone cyst-like areas. Immunohistochemical studies for CD34, CD99, S-100 protein and cytokeratin were performed. Tumor cells were diffusely positive for S-100 protein in three cases and weakly positive for cytokeratin in one case. CD34 and CD99 were negative in all cases. In summary, chondroblastoma of the temporal bone is rare and occurs in older age group than reported cases of chondroblastoma of the usual location in the literature.

CT evaluation of primary epiphyseal bone abscesses

We reviewed the clinical, radiographic, and computed tomographic (CT) findings in eight children with a histologically proven diagnosis of epiphyseal or apophyseal osteomyelitis. In all cases the femur was involved: in five the osteomyelitis was localized in the femoral condyle, in two it was in the greater trochanter, and in one it was in the femoral head epiphysis. In four of the six cases of epiphyseal involvement there was associated joint effusion or septic arthritis. CT examination may demonstrate a serpentine tract, a sequestrum, cortical destruction or adjacent soft tissue swelling and can differentiate osteomyelitis from other epiphyseal lucent lesions, particularly chondroblastoma and osteoid osteoma. CT yielded important new diagnostic information in seven of the eight patients, failing to do so in only one. In one case, CT showed a wooden splinter in an abscess cavity, which had been mistaken for a sequestrum. When combined with accurate clinical and laboratory information and good quality plain radiographs, CT can lead to an early diagnosis of epiphyseal infection. Early diagnosis helps avoid delays in initiating antibiotic or surgical treatment caused by the unusual (epiphyseal or apophyseal) location of the bone abscess.

Metaphyseal and diaphyseal chondroblastomas

OBJECTIVE

Epiphyseal/apophyseal locations are important diagnostic radiological features of chondroblastomas (CB). Although the tumor may secondarily involve the metaphysis, reports of primary metaphyseal or diaphyseal CB without any epiphyseal or apophyseal involvement are exceptionally rare and frequently present as a diagnostic dilemma. The purpose of this study was to present seven cases of pure metaphyseal and/or diaphyseal CB along with a review of pertinent literature.

METHODS

A retrospective review of databases at two major referral centers revealed 390 cases of CB between 1960 and 2009. Out of these, seven histologically proven CB cases (1.8%) were found to be radiologically located in metaphysis and/or diaphysis, without involving the epiphysis and/or apophysis, and formed the study cohort.

RESULTS

There were four males and three females (age range 2-25 years). Locations included proximal femur (n = 1), distal femur (2), proximal humerus (2), clavicle (1), and proximal radius (1). All lesions showed marginal sclerosis. A periosteal reaction was seen in five cases (71%), cortical expansion in four cases (57%), and chondroid matrix in four cases (57%). A CT (two cases) demonstrated a matrix in both cases. An MR (one case) showed extensive perilesional edema. Bone scan (one case) showed intense uptake.

CONCLUSION

Pure metaphyseal and/or diaphyseal CB are exceedingly rare. A presumptive diagnosis may be considered in the appropriate age group in the presence of chondroid matrix, perilesional edema, periosteal reaction, and marginal sclerosis. Regardless of all the diagnostic possibilities, biopsy may still be required. However, knowledge of this entity will help make the final diagnosis and guide the correct treatment.

Markers aiding the diagnosis of chondroid tumors: an immunohistochemical study including osteonectin, bcl-2, cox-2, actin, calponin, D2-40 (podoplanin), mdm-2, CD117 (c-kit), and YKL-40

Chondroid tumors comprise a heterogenous group of benign to overt malignant neoplasms, which may be difficult to differentiate from one another by histological examination. A group of 43 such tumors was stained with nine relevant antibodies in an attempt to find consistent marker profile(s) for the different subgroups. Archival material from three extraskeletal myxoid chondrosarcomas, five chordomas, five chondromyxoid fibromas, five chondroblastomas and 25 chondrosarcomas was stained with antibodies against osteonectin, bcl-2, cox-2, actin, calponin, D2-40 (podoplanin), mdm-2, CD117 (c-kit) and YKL-40. All 25 chondrosarcomas showed a positive staining reaction for D2-40, none for actin and CD117, and a partial reactivity for bcl-2 (36%). Chondroblastomas (5/5) and chondromyxoid fibromas (2/5) were the only tumors with a positive reaction for actin, and all chondroblastomas (n=5) and extraskeletal myxoid chondrosarcomas (n=3) were positive for bcl-2. In contrast to all other tumors, two of three extraskeletal myxoid chondrosarcomas were also positive for CD17 and negative for osteonectin, cox-2, mdm-2 and actin. All five chordomas were negative for D2-40 and positive for mdm-2 and YKL-40. The diagnosis of chondrosarcoma may be aided by its positivity for D2-40 and YKL-40 and its lack of reactivity for actin and CD117. This should be seen in the light of no reaction for D2-40 in chordomas and a corresponding lack of reaction for osteonectin, cox-2, mdm-2 and actin in extraskeletal myxoid chondrosarcomas. A convincing immunoreactivity for calponin and/or actin in chondromyxoid fibromas and chondroblastomas may also be helpful in differentiating these tumors from chondrosarcomas.

Chondromyxoid fibroma of paranasal sinuses: report of two cases presenting with nasal obstruction

Chondromyxoid fibroma (CMF) is a rare, benign cartilaginous tumor that often occurs in the metaphyses of long bones. Tumors of the craniofacial bones are extremely rare and most often involve the mandible and the maxilla. This report presents the clinicopathological and radiological features of two unusual cases of CMF arising in the paranasal sinuses that presented with nasal obstruction. The tumors arose in the sphenoid and ethmoid sinuses and were treated by curettage and resection, respectively. One of the two patients was 20 days old, suggesting a possible congenital origin.