Patterns of brachyury expression in chordomas.

INTRODUCTION: Chordomas are rare malignant midline tumors, presumed to arise from notochordal remnants. This was further suggested by the discovery of the brachyury in chordomas pathogenesis. Its immunohistochemical expression has become the principal adjunct in the diagnosis of chordomas. However, studies about brachyury expression in chordomas are not fully comparable, mainly because they use different primary antibodies. Thus, the aim of this study is to investigate the expression of brachyury expression in a series of chordomas in conjunction to clinicopathological characteristics and to review the relevant literature providing all the details needed in the immunohistochemical study of brachyury. MATERIALS AND METHODS: This is a retrospective study of 62 chordomas, diagnosed over a 22-year period. No dedifferentiated or poorly differentiated cases were included. A monoclonal primary antibody (clone A-4) was used and brachyury expression was evaluated by the H-score. Clinicopathological parameters studied were age, sex, tumor localization, decalcification status and tissue age. Fetal notochords were used for comparison. RESULTS: Mean H-score of nuclear brachyury expression was 129.8. The tissue age significantly influenced brachyury expression, the older samples expressing less brachyury. Decalcification demonstrated a trend to weaken brachyury expression. Clinical characteristics were not correlated with the patterns of brachyury expression. Notochords were negative. Literature review reveals several polyclonal antibodies used and a positivity of 75%-100% in chordomas with even more variable results in notochords. CONCLUSION: In chordomas, as in other tumor types, an uniformization of studies about brachyury expression is needed, by considering the clone used, and the decalcification and the age of the sample, given the growing importance of brachyury in diagnosis and therapeutic steps.

EM proves invaluable in the confirmation of chordoma in the sacral mass of a middle-aged man.

A case of a 47-year-old male with a sacral spine mass was investigated by histology, immunohistochemistry (IHC), and electron microscopy (EM). The light microscopy of the first core biopsy revealed scant cellularity with spindle and round cells with eosinophilic cytoplasm within a fibromyxoid background. Immunostaining with pancytokeratin, cytokeratin 19, and S100 was nonspecific. Another biopsy was attempted to obtain a more definitive diagnosis. Light microscopy of the second core had scant cellular material. However, the tissue was specifically requested for ultrastructural evaluation and revealed features diagnostic of chordoma. After definitive diagnosis, radical resection of the mass was performed. This case illustrates how EM was instrumental in the definitive diagnosis before radical resection in a case that was not clear by hematoxylin and eosin (H&E) and IHC alone.

Chondroid chordoma of the skull base: immunohistochemical and ultrastructural study of two cases with special reference to microtubules within rough-surfaced endoplasmic reticulum.

Two cases of skull base chordoma (case 1, a 57-year-old woman; case 2, a 69-year-old woman) were investigated immunohistochemically and ultrastructurally. The tumors showed histopathological features typical of chondroid chordoma and contained both classical chordomatous and hyaline cartilaginous components. Tumor cells were immunoreactive for cytokeratin, vimentin, and S-100 protein, but negative for microtubule-associated protein 2 and class III beta-tubulin (tub-B3). Tumor cells of case 2 were immunoreactive for tau-protein and class II beta-tubulin (tub-B2), whereas those of case 1 were negative. Ultrastructurally, tumor cells in both cases showed the presence of abundant glycogen granules, well-developed intracellular organelles, and desmosome-like junctions. In case 2, several microtubules were closely packed and ran parallel or in random directions within the dilated cisterns of rough-surfaced endoplasmic reticulum (rough ER). "Microtubules within rough ER" has been described in several neoplasms, including classical and chondroid chordomas. Although previous reports documented the tub-B3 immunoreactivity in chordomas, our results suggested that, in our case 2, the predominant isoform of beta-tubulin in microtubules within rough ER was not tub-B3 but tub-B2.

MRI Signal Intensity and Electron Ultrastructure Classification Predict the Long-Term Outcome of Skull Base Chordomas.

BACKGROUND AND PURPOSE: MR imaging is a useful and widely used evaluation for chordomas. Prior studies have classified chordomas into cell-dense type and matrix-rich type according to the ultrastructural features. However, the relationship between the MR imaging signal intensity and ultrastructural classification is unknown. We hypothesized that MR imaging signal intensity may predict both tumor ultrastructural classification and prognosis. MATERIALS AND METHODS: Seventy-nine patients with skull base chordomas who underwent 95 operations were included in this retrospective single-center series. Preoperative tumor-to-pons MR imaging signal intensity ratios were calculated and designated as ratio on T1 FLAIR sequence (RT1), ratio on T2 sequence (RT2), and ratio on enhanced T1 FLAIR sequence (REN), respectively. We assessed the relationships among signal intensity ratios, ultrastructural classification, and survival. RESULTS: Compared with the matrix-rich type group, the cell-dense type chordomas showed lower RT2 (cell-dense type: 1.90 ± 0.38; matrix-rich type: 2.61 ± 0.60 P < .001). The model of predicting cell-dense type based on RT2 had an area under the curve of 0.83 (95% CI, 0.75-0.92). In patients without radiation therapy, both progression-free survival (P = .003) and overall survival (P = .002) were longer in the matrix-rich type group than in the cell-dense type group. REN was a risk factor for progression-free survival (hazard ratio = 10.24; 95% CI, 1.73-60.79); RT2 was a protective factor for overall survival (hazard ratio = 0.33; 95% CI, 0.12-0.87); and REN was a risk factor for overall survival (hazard ratio = 4.76; 95% CI, 1.51-15.01). CONCLUSIONS: The difference in MR imaging signal intensity in chordomas can be explained by electron microscopic features. Both signal intensity ratios and electron microscopic features may be prognostic factors.

[Chordomas]. / Les chordomes.

Chordoma is a rare bone tumor, believed to derive from notochordal rests, which generally arises at the two extremities of axial skeleton. We present a literature review on chordomas. Diagnosis has been greatly improved by MRI and immunohistochemistry. Conversely, complementary immunohistochemistry, cytometry and cytogenetic techniques have failed to improve prognosis evaluation. Radical surgery with free surgical margins is the most accurate curative treatment. Progress in radiotherapy should offer new therapeutic perspectives in the future. The recognition of new entities such as giant notochordal rest or hamartoma, and notochordal cells benign tumor, can lead to confusion since there is no consensus regarding their nature and whether or not they correspond to chordoma precursors. Prudence should be the rule in order to avoid overtreatment.

Prognostic Value of a Category Based on Electron Microscopic Features of Clival Chordomas.

OBJECTIVE: Skull base chordomas are clinically malignant because of the difficulty of total removal and the high recurrence rate. Because the disease-free survival after surgery is currently unpredictable, there is a need for new parameters, obtained from histologic analyses of the resection specimen, that allows a risk stratification of patients with chordoma. METHODS: In recent years, electron microscopic diagnoses were introduced into the clinical practice for the diagnosis of chordoma in our department. Clinical outcomes and electron microscopic features were retrospectively reviewed in the study. The electron micrograph shows that clival chordoma can be divided into cell-dense type (CDT) and matrix-rich type (MRT). Of all the patients with chordoma, complete data from 27 patients were obtained. There were 12 patients in the CDT group and 15 patients in the MRT group. The paraffin-embedded tissue samples were stained with Ki-67 antibody. The prognostic values of electron microscopic classification were compared between the 2 groups. RESULTS: There were no statistical differences in the gender (P = 0.704) and age distribution (P = 0.243) between the 2 groups. There was also no statistical difference concerning the constitution of primitive tumors and recurrent tumors between the 2 groups (P = 0.706). The CDT group had a higher mortality rate than the MRT group (P = 0.037). The tumors in the CDT group were prone to recurrence and the need for reoperation within 1 year after surgery, which is statistically different from that in the MRT group (P < 0.001). Chordoma tumors of 23 patients (85.2%) stained positive for Ki-67. CDT chordomas had a higher Ki-67 proliferation index than the MRT chordomas (P = 0.013). CONCLUSIONS: The present study demonstrates the utility of the ultrastructural features in the prognostic outcome of patients with chordoma. According to the ultrastructures of chordomas, they can be divided into CDT and MRT. CDT chordoma cells have a more aggressive proliferative ability. Patients with CDT have a poor prognostic factor in clival chordoma, which has a higher risk of recurrence and a shorter survival.

Chondroid chordoma. Electron-microscopic study of two cases.

Chondroid chordoma is an unusual tumor composed of an admixture of chondromatous and chordomatous tissue usually located in the spheno-occipital region. This tumor shares many of the clinical and histologic features of classic chordoma and chondrosarcoma and has been shown to have a better prognosis than either of these lesions. To the best of our knowledge, no ultrastructural studies have been performed in the 26 cases of chondroid chordoma published previously. We document the ultrastructural features of two examples of chondroid chordoma. Certain features such as prominent and dilated rough endoplasmic reticulum, intracytoplasmic glycogen aggregates, and abundant fibrillogranular matrix are common to chordoma, chondrosarcoma, and chondroid chordoma. The presence of well-formed tonofilament desmosome complexes as well as complexes composed of alternating profiles of rough endoplasmic reticulum and mitochondria were seen only in chordoma and chondroid chordoma, but not in cartilaginous tumors. Of particular interest was the finding of crystalline, tubular structures within the rough endoplasmic reticulum of both cases of chondroid chordoma, a finding not described previously. The distinction of chondroid chordoma from classical chordoma is said to be a difficult one at the light-microscopic level, and we suggest that these intraergastoplasmic tubular structures might constitute an extremely helpful differential marker.

Chordomas of the mediastinum: clinicopathologic, immunohistochemical, and ultrastructural study of six cases presenting as posterior mediastinal masses.

Six cases of chordomas presenting as primary posterior mediastinal tumors are described. Three patients were female, and three were male between the ages of 8 and 65 years (mean, 40.6 years). In all cases, the tumors presented radiographically as relatively well-circumscribed, encapsulated soft tissue masses that did not seem to be related to the thoracic or dorsal spine. Only in one case, focal infiltration of bone at the level of T6-T7 was observed at the time of surgery. Histologically, the lesions showed a spectrum of features that ranged from sheets and cords of large cells with abundant vacuolated cytoplasm to small, stellate cells embedded within an abundant mucoid matrix. In one case, the cell population showed more pronounced nuclear atypia with loss of cytoplasmic vacuolization, frequent mitotic figures, necrosis, and solid areas characterized by a perivascular distribution of atypical spindle cells set against a myxoid stroma. Another case showed features of chondroid chordoma, with an immature chondroid-appearing matrix surrounding the atypical tumor cells. Immunohistochemical studies in all cases showed positive staining of the tumor cells with CAM 5.2 and broad-spectrum keratin, epithelial membrane antigen (EMA) and vimentin, and, to a lesser extent, with S-100 protein. Stains for muscle actin, carcinoembryonic antigen (CEA), and desmin were negative. Ultrastructural examination in two cases showed a spectrum of features that varied from large cells with abundant cytoplasm containing scattered ribosomes, glycogen granules, Golgi apparatti, abundant intermediate filaments, and small lumen formation with immature microvilli to smaller cells with elongated cytoplasmic processes, fewer intermediate filaments, rare desmosome type intercellular junctions, and complexes of mitochondria/rough endoplasmic reticulum. On clinical follow-up, two patients died with metastases to the lungs, chest wall, and liver from 1 to 3 years after diagnosis, and two patients are alive and well without evidence of disease after 3 and 16 years. Chordoma should be entertained in the differential diagnosis of posterior mediastinal tumors. Application of immunohistochemical stains or electron microscopy will be of aid in separating them from other conditions that may histologically closely resemble these lesions.

Malignant fibrous histiocytoma within a recurrent chordoma. A light microscopic, electron microscopic, and immunohistochemical study.

A histologically typical chordoma and its four recurrences (3.5, 4, 7, and 7.5 years later) were operated from the spinal canal and I-III lumbar vertebrae of a 49-year-old woman. In addition to the typical areas of chordoma, pleomorphic areas resembling malignant fibrous histiocytoma also were seen in the fourth recurrence. The chordoma-like areas of the fourth recurrence displayed typical epithelial features: clusters of epithelial-like cells, electron microscopically demonstrable vacuoles lined by microvilli and desmosomes, and cytokeratin positivity in immunostaining. The areas in the fourth recurrence that resembled malignant fibrous histiocytoma lacked epithelial features as judged by electron microscopy. They also were negative for cytokeratin but contained, instead, vimentin type of intermediate filaments. The results show that the sarcomatous areas as seen in the recurrent chordoma lack epithelial cell features of chordoma and suggest the possibility of altered differentiation pathway of the tumor stem cell or emergence of a new malignant cell population within the recurrent tumor.

Cytogenetic analysis of a parachordoma.

We report the cytogenetic and histopathological findings in a 7-year-old female child with an intranasal tumor that is most consistent with a parachordoma. Karyotypic analysis of the tumor revealed clonal numerical and structural chromosome abnormalities. Seven cells displayed recurrent changes: der(2)t(2;4), del(3q), and the loss of chromosomes 9, 10, 20, and 22. Four cells showed a loss of chromosome 17. To the best of our knowledge, these are the first clonal chromosome abnormalities described in parachordoma.

A comparative ultrastructural study of chondrosarcoma, chordoid sarcoma, chordoma and chordoma periphericum.

The present study is based on electron microscopical examinations of 15 conventional chondrosarcomas, 1 clear cell chondrosarcoma, 3 mesenchymal chondrosarcomas, 2 so-called chordoid sarcomas (extraskeletal myxoid chondrosarcoma), 4 sacrococcygeal chordomas, 2 ecchordoses and 1 neoplasm of tibia with features of a true peripheral chordoma (parachordoma). The neoplastic cells from various types of chondrosarcoma shared a number of features with nonneoplastic chondrocytes as e.g. a well-developed rough endoplasmic reticulum and microvillous cytoplasmic processes. In clear-cell chondrosarcoma, glycogen accumulation in the tumour cells was a prominent feature. The cells of mesenchymal chondrosarcoma usually showed the characteristics of immature mesenchymal cells. In contrast, chordomas commonly contained physaliferous cells with two types of vacuoles in their cytoplasm. The first type can be most adequately characterized as intracytoplasmic pseudoinclusions of intercellular substance, whereas the other type, glycogen-containing, single membrane-bound vacuoles most probably correspond to autophagosomes (cytolysosomes). Only vacuoles of the first type were recorded in the so-called chordoid sarcoma. They were also seen in chondrosarcomas. In contrast, both types of vacuoles were identified in the above-mentioned tibial tumour which, in addition, showed even other cytological characteristics of chordoma. The findings presented here have demonstrated distinct structural relationships between chordoid sarcoma and chondrogenic tumours. On the other hand, our observation of the uncommon tibial neoplasm indicates the possibility that tumours identical with chordoma may occur at sites other than the axial skeleton.

The nature of cytoplasmic vacuoles in chordoma cells. A correlative enzyme and electron microscopic histochemical study.

Enzyme histochemical study revealed that a sacrococcygeal chordoma not only was rich in oxidoreductive enzymes but also in the enzymes (phosphorylase, hexokinase, phosphoglucomutase, glucose phosphate isomerase and UDP-glucose dehydrogenase) leading to the synthesis of stromal glycosaminoglycans from glycogen. UDP-glucose dehydrogenase is particularly important in oxidizing UDP-glucose to UDP-glucuronic acid, the building block of hyaluronic acid and chondroitin sulfates. These enzymatic activities were consistent with the ultrastructural findings of abundant membrane-bound glycogen as well as large intracytoplasmic vacuoles with occasional residual glycogen particles. Furthermore, ultrastructural histochemical study using high iron diamine (HID) specifically localized the sulfated glycosaminoglycans (SG) extracellularly as well as intracellularly in distended Golgi saccules and 187-320 nm mature secretory vesicles. No HID staining was noted in the large intracytoplasmic vacuoles or rough endoplasmic reticulum. This study not only supports the hypothesis that the vacuoles of physaliphorous cells are the result of breakdown and utilization of membrane bound glycogen in the biosynthesis of SG, but also demonstrates that intracellular synthesis and storage of SG in chordoma are not in large vacuoles as previous investigators have believed.

Ecchordosis physaliphora and chordoma: a comparative ultrastructural study.

A comparative study of the ultrastructure of two cases of ecchordosis physaliphora and of two chordomas demonstrated outstanding similarities in the cells composing these two entities. Chordoma cells possessed a more prominent Golgi apparatus, an endoplasmic reticulum-mitochondria complex, plasmalemmal infoldings, nuclear irregularities and a larger extracellular space with abundant matrix, reflecting their expanding neoplastic nature. Ecchordosis cells had nuclear inclusions, dense-core membrane-bound granules and subcytoplasmalemmal linear densities, not previously described. Both ecchordosis and chordoma cells have morphologic features of both epithelial and mesodermal character. This study supports the concept that chordomas arise from heterotopic notochordal remnants in the cranio-vertebral canal.

Microtubule aggregates in a clival chordoma.

We report a case of a clival chordoma in a 21-year-old man that ultrastructurally demonstrated large numbers of microtubule aggregates within the rough endoplasmic reticulum. Histologically, the tumor demonstrated classic chordoma architecture characterized by numerous physaliphorous cells and an abundant extracellular matrix. The tumor cells stained strongly for cytokeratin, S100 protein, and epithelial membrane antigen, indicative of the epithelial origin of this tumor. Ultrastructurally, the most conspicuous feature of this tumor consisted of parallel bundles of criss-crossing microtubules within the rough endoplasmic reticulum. These microtubules had a diameter of approximately 27 nm and did not demonstrate an internal structure. To our knowledge, this is the first report of microtubule aggregates in a spheno-occipital chordoma. We note that microtubule aggregates have been described in a number of different entities, and though proposed as a specific feature of "chondroid chordoma," they are a nonspecific finding.

Chordoma: diagnosis by fine-needle aspiration biopsy with histologic, immunocytochemical, and ultrastructural confirmation.

Five cases of chordoma, diagnosed by fine-needle aspiration (FNA) biopsy, are presented. Four cases were histologically confirmed, and in one, immunocytochemical and ultrastructural studies were performed on both the aspirate and tissue specimen. Four cases presented as sacral masses, while in the fifth case, a destructive lesion of the clivus extended into the soft tissues of the lateral neck. A spectrum of cytomorphologic features was encountered including the presence of abundant microtissue fragments and cells in a dissociate pattern, often with abundant metachromatic extracellular matrix. Stellate and cuboidal cells often contained intracytoplasmic vacuoles of varying sizes. Intranuclear inclusions, mitotic figures, and anisonucleosis were prominent features of several cases. Immunoperoxidase studies on a single case demonstrated cytoplasmic staining for low- and high-molecular-weight cytokeratins, vimentin, and epithelial membrane antigen, while glial fibrillary acidic protein and carcinoembryonic antigen were negative. Ultrastructural features included the presence of mitochondrial endoplasmic reticulum complexes, occasional desmosome-like junctions, and abundant extracellular matrix adherent to the tumor cells. We believe the cytomorphologic findings are characteristic and, when taken in concert with immunocytochemical and ultrastructural studies, allow differentiation of chordoma from other primary or metastatic neoplasms occurring in bone. As demonstrated in our series, chordoma is often an unsuspected diagnosis. We believe that FNA biopsy of these lesions can lead to a correct preoperative diagnosis and may also be utilized to document recurrence and thus facilitate the evaluation and management of patients with these lesions.

Chondroid chordoma: fine-needle aspiration cytology with histopathological, immunohistochemical, and ultrastructural study of two cases.

Chondroid chordoma is a controversial and confusing entity that was originally described by Heffelfinger et al. (Cancer 1973; 32:410-420) as a biphasic malignant neoplasm possessing elements of both chordoma and cartilaginous tissue. Fine-needle aspiration (FNA) cytology of chondroid chordoma has not been described. The aim of our investigation was to characterize the chondroid area of chondroid chordoma and to compare the FNA features with those of well-differentiated chondrosarcoma. Clival and cervical spine chondroid chordomas were studied with light microscopy, immunohistochemistry, and electron microscopy. Chondroid chordomas demonstrated an epithelial nature by immunohistochemistry and ultrastructural studies. The FNA smears showed low cellularity, with loosely arranged or dispersed round cells in a myxoid background. Although the smears were similar to those of well-differentiated chondrosarcomas, they showed a positive reaction for epithelial markers. These findings reveal that chondroid chordoma is a variant of chordoma which possesses a hyaline matrix. Immunohistochemical demonstration of epithelial markers is useful to distinguish it from chondrosarcoma. Diagn. Cytopathol. 1999; 21:335-339.

Cytologic, cytochemical, immunocytochemical and ultrastructural diagnosis of a sacrococcygeal chordoma in a fine needle aspiration biopsy specimen.

The cytologic, cytochemical, immunocytochemical and ultrastructural findings on the aspirated material are presented for the case of a 57-year-old man with sacrococcygeal chordoma diagnosed by fine needle aspiration biopsy. Cytologically, two types of cellular elements were differentiated: medium-sized cells with few cytoplasmic vacuoles and classic physaliferous cells. Both types showed marked cytoplasmic positivity for keratin and S-100 protein; the absence of nuclear positivity in the physaliferous cells was notable. Ultrastructural study demonstrated the existence of true intracytoplasmic vacuoles and frequent rough endoplasmic reticulum-mitochondria complexes. The cytologic differential diagnosis with chondrosarcoma, myxoid liposarcoma, ependymoma and metastases of mucosecretory carcinomas is reviewed.

Intracisternal microtubular aggregates in classic (non chondroid) chordoma.

A case of unequivocal and classic (non chondroid) chordoma with cells including microtubular aggregates is reported. Parallel arrays of straight or slightly curved and evenly spaced 22-26 nm microtubules, showing a fine periodicity and without internal structure, were confined within dilated cisternae. These cisternae were characterized by a single layered limiting membrane, without associated ribosomes. This is the second reported occurrence of such microtubules in a spheno-occipital classic chordoma. It emphasizes the nonspecificity of this finding namely in reference to extraskeletal myxoid chondrosarcoma or chondroid chordoma. Furthermore, intracytoplasmic true lumina were found to partly account for the cellular vacuolar character on light microscopy, an observation generally underscored in chordoma cells.

Chordoma in a cat.

A chordoma within the deep musculature adjacent to C3 and C4 was excised from a 14-year-old castrated domestic cat. Metastatic chordoma developed in a prescapular lymph node 10 months later. At necropsy 11 months after complete excision of the primary tumor, metastases were found in both retropharyngeal lymph nodes.