Chondroid chordoma versus low-grade chondrosarcoma of the base of the skull: can immunohistochemistry resolve the controversy?

Coccygeal chordoma in a degu: case report and review of the literature

An 8-y-old, intact female degu ( Octodon degus) was presented with a slow-growing mass on the tail tip. The mass was completely removed by partial caudectomy. Histologically, the last coccygeal vertebra was replaced by a lobulated neoplasm composed of large clear polygonal cells embedded in a myxoid alcian blue-positive matrix with highly vacuolated cytoplasm (physaliferous cells) and intracytoplasmic periodic acid-Schiff-positive granules. The neoplasm exhibited the morphologic features of a "classic" chordoma of humans, which is 1 of 3 distinct chordoma subtypes. Immunohistochemistry revealed dual expression of cytokeratin AE1/AE3 and vimentin, consistent with a diagnosis of chordoma. Chordomas are uncommon slow-growing neoplasms in humans and animals, arising from notochordal remnants. Depending on their subtype and location, they can have a high local recurrence rate and metastatic risk. Chordoma should be included in the differential diagnosis of a soft tissue mass on the tail of a degu, similar to the clinical situation in ferrets.

Pituitary fossa chondrosarcoma: An unusual cause of a sellar suprasellar mass masquerading as pituitary adenoma

Background

Chondrosarcoma is a mesenchymal malignant tumor composed of tumor cells producing cartilage. It is more commonly found in older age group and usually affects the axial skeleton. Intracranial chondrosarcoma is extremely rare, and chondrosarcoma arising from the sellar region are even rarer with only a few cases described in the literature. We report a case of chondrosarcoma mimicking a sellar suprasellar mass with parasellar extension.

Case Description

A 22-year old male presented with generalized intermittent headache along with diplopia and diminished visual acuity without any history of sexual dysfunction or galactorrhea. His endocrine tests were within normal limits. Magnetic resonance imaging of the brain revealed a large mass which was apparently arising from the sella with a significant suprasellar and left parasellar component with mild compression over the left optic chiasm and deviation of infundibulum to the right. The patient underwent pterional craniotomy and decompression of the mass. The pathologic diagnosis was chondrosarcoma. The patient received postoperative radiotherapy.

Conclusion

This case demonstrates that chondrosarcoma of the sellar region may mimic clinical, endocrinological, and radiological features of more commonly encountered lesions in this region such as nonfunctioning pituitary tumor, craniopharyngioma, meningioma, or chordoma. We discuss the origin, areas of involvement, management, and long-term prognosis of these rare tumors.

State-of-the-Art Imaging in Human Chordoma of the Skull Base

Purpose of Review

Chordoma are rare tumours of the axial skeleton which occur most often at the base of the skull and in the sacrum. Although chordoma are generally slow-growing lesions, the recurrence rate is high and the location makes it often difficult to treat. Both computed tomography (CT) and magnetic resonance imaging (MRI) are crucial in the initial diagnosis, treatment planning and post-treatment follow-up.

Recent Findings

Basic MRI and CT characteristics of chordoma were described in the late 1980s and early 1990s. Since then, imaging techniques have evolved with increased resolution and new molecular imaging tools are rapidly evolving. New imaging tools have been developed not only to study anatomy, but also physiologic changes and characterization of tissue and assessment of tumour biology. Recent studies show the uptake of multiple PET tracers in chordoma, which may become an important aspect in the diagnosis, follow-up and personalized therapy.

Summary

This review gives an overview of skull base chordoma histopathology, classic imaging characteristics, radiomics and state-of-the-art imaging techniques that are now emerging in diagnosis, treatment planning and disease monitoring of skull base chordoma.

A historical recount of chordoma

Chordoma, a rare bone tumor that occurs along the spine, has led scientists on a fascinating journey of discoveries. In this historical vignette, the authors track these discoveries in diagnosis and treatment, noting events and clinicians that played pivotal roles in our current understanding of chordoma. The study of chordoma begins in 1846 when Rudolf Virchow first observed its occurrence on a dorsum sellae; he coined the term “chordomata” 11 years later. The chordoma’s origin was greatly disputed by members of the scientific community. Eventually, Müller’s notochord hypothesis was accepted 36 years after its proposal. Chordomas were considered benign and slow growing until the early 1900s, when reported autopsy cases drew attention to their possible malignant nature. Between 1864 and 1919, the first-ever symptomatic descriptions of various forms of chordoma were reported, with the subsequent characterization of chordoma histology and the establishment of classification criteria shortly thereafter. The authors discuss the critical historical steps in diagnosis and treatment, as well as pioneering operations and treatment modalities, noting the physicians and cases responsible for advancing our understanding of chordoma.

Paediatric Chordomas

Paediatric chordomas are rare malignant tumours arising from primitive notochordal remnants with a high rate of recurrence. Only 5 % of them occur in the first two decades such less than 300 paediatric cases have been reported so far in the literature. In children, the average age at diagnosis is 10 years with a male-to-female ratio closed to 1. On the opposite to adults, the majority of paediatric chordomas are intracranial, characteristically centered on the sphenooccipital synchondrosis. Metastatic spread seems to be the prerogative of the under 5-year-old children with more frequent sacro-coccygeal locations and undifferentiated histology. The clinical presentation depends entirely on the tumour location. The most common presenting symptoms are diplopia and signs of raised intracranial pressure. Sacrococcygeal forms may present with an ulcerated subcutaneous mass, radicular pain, bladder and bowel dysfunctions. Diagnosis is suspected on computerised tomography showing the bone destruction and with typically lobulated appearance, hyperintense on T2-weighted magnetic resonance imaging. Today, treatment relies on as complete surgical resection as possible (rarely achieved because of frequent invasiveness of functional structures) followed by adjuvant radiotherapy by proton therapy. The role of chemotherapy has not been proven. Prognosis is better than in adults and depends on the extent of surgical resection, age and histology subgroup. Biological markers are still lacking to improve prognosis by developing targeted therapy.

Skull base chondroid chordoma: atypical case manifesting as intratumoral hemorrhage and literature review

OBJECTIVE

Chondroid chordoma (CC) is a rare but commonest subtype of chordoma with little reported clinical information. The present study summarizes and updates present knowledge of CC.

METHODS

Literature search for demographic data and clinical appearance of cranial CCs except for those entirely confined to the sinonasal region.

RESULTS

A total of 48 English language papers published from 1968-2013 were retrieved describing 132 CCs as skull base tumors. The male-to-female ratio was 1:1. The mean age at diagnosis was 43 years, predisposing to the third to fifth decades of life. The clival (34%) and spheno-occipital (29%) regions were the most frequent sites of origin followed by the sellar (12%) and sphenoid (5%) regions. Intratumoral calcification and bony erosion were identified as the characteristic neuroimaging findings. Surgical resection by the transcranial, transsphenoidal, transnasal, transpharyngeal, or transpalatal route with or without adjuvant radiotherapy was the main treatment option. The initial treatment outcome was satisfactory in 82% of cases with considerably better prognosis compared with typical chordomas.

CONCLUSION

CC is a distinct entity to be discriminated from the typical type of chordoma. There are no distinguishing features on magnetic resonance imaging between CC and typical chordoma. Intratumoral calcification and concurrent bony erosion on neuroimaging should suggest the possibility of CC. Extensive surgical resection and adjuvant radiotherapy can achieve satisfactory outcome.

Chondroid chordoma in an atypical location

Chondroid chordoma is an extremely rare tumour with an annual incidence of around 0.1 cases per 100,000population. Involvement of the thoracic vertebrae may be present in 2-5% of cases. Definitive diagnosis usually requires a suitable distinction between this and other mesenchymal tumours such as chondrosarcomas, so immunohistochemical analysis is virtually mandatory. In spite of its slow-growing nature, chondroid chordoma tends to relapse, and it may eventually become malignant, often jeopardising the patient's prognosis. Although surgery remains the main therapeutic approach, research into the molecular and genetic aspects of this tumour is ongoing. These new advances are likely to improve future oncology therapies by complementing surgery and radiotherapy, changing the currently poor prognosis. We report the case of a patient with a chondroid chordoma involving the thoracic vertebrae and pleural cavity, and the treatment performed.

Cervical chondroid chordoma in a standard dachshund: a case report

A ten-year-old male standard dachshund was presented with a history of neck pain and progressive gait disturbances. Following a neurological examination and diagnostic imaging, including CT, a neoplastic lesion involving the third and fourth cervical vertebrae was suspected. The lesion included an extradural mass on the right side of the spinal canal causing a local compression of the cervical cord. Surgery, using a modified dorsal laminectomy procedure, was performed in order to decompress the cervical spinal cord. Histopathological examination of the extradural mass indicated that the tumour was a chondroid chordoma. Following discharge, the quality of life for the dog was very good for a sustained period, but clinical signs recurred at 22 months. The dog was euthanased 25 months post-surgery. On post-mortem examination, a regrowth of neoplastic tissue was found to have infiltrated the bone and spinal cord at C3-C4. This is the first report to show that palliative surgery can offer successful long-lasting treatment of chondroid chordoma of the cervical spine in the dog.

Chordoma in the tail of a ferret

A chordoma is an uncommon tumor that originates from the remnants of the notochord and most commonly involves the cranial and caudal regions of the axial skeleton. Chordoma has been described in laboratory animals such as dogs, rats, minks, and ferrets. This report describes a case of a chordoma in the tail of a ferret. Grossly, a grayish-white, expansile, subcutaneous soft-tissue mass was observed in the tail. Histopathologically, the mass was a loosely placed, nodular, unencapsulated neoplasm within the dermis. In the mass, tumor lobules were intermingled with fibrous tissues. Fibrous tissues contained abundant extracellular basophilic material that was consistent with mucin. The tumor was composed of a close pack of adipocyte-like vacuolated cells (physaliferous cells). The cells were centrally or eccentrically located round nuclei and eosinophilic cytoplasm with large vacuoles. Immunohistologically, neoplastic cells were positive for vimentin and S-100 protein. Based on histopathologic findings and special staining characteristics, this case was diagnosed as chordoma.

Chordoid meningioma: a clinicopathologic study of 11 cases at a single institution

Chordoid meningioma is an uncommon variant of meningioma, which histologically bears a great resemblance to chordoma and often follows an aggressive clinical course. We examine clinicopathologic features of 11 cases of this rare tumor to further elucidate its behavior. Thirteen specimens of chordoid meningioma belonging to 11 patients were obtained at a single institution from 1995 to 2009. Correlations of histologic parameters, immunohistochemical study, and clinical features were assessed. This series included six men and five women with a mean age of 60.8 years at first surgery. Aside from one patient (case 5) who died of disease immediately after the first operation, the mean postoperative follow-up period for the other 10 patients was 41.4 months. Two patients each had a local tumor recurrence. The mean time to recurrence was 10.4 years. No systemic manifestations of Castleman syndrome, such as iron-refractory hypochromic/microcytic anemia and dysgammaglobulinemia, were found. Six tumors (46%) were classified as benign (grade I) and seven tumors (54%) atypical (grade II), if based solely on histologic grading irrespective of chordoid or clear cell components in our cases. Lymphoplasmacytic infiltrate was moderate in one tumor (7%), mild in eight tumors (62%), and absent in four tumors (31%). The inflammatory cells were predominantly T cells (CD3+), with only scarce B cells (CD20+). There was a wide range of MIB-1 labeling indices (0.3-25.8%, mean 7.5%), which increased following tumor recurrence. Our study demonstrates that chordoid meningiomas are not always associated with Castleman's Syndrome, and that this histologic category can be seen in the elderly as opposed to only in younger age groups.

Immunohistochemical comparison of chordoma with chondrosarcoma, myxopapillary ependymoma, and chordoid meningioma

Chordoma originates from embryonic notochordal remnants in the midline along the spinal axis and is characterized by cords and lobules of neoplastic cells arranged within myxoid matrix. Because of histologic similarities with myxoid matrix and overlapping immunohistochemical profile, chondrosarcoma, myxopapillary ependymoma, and chordoid meningioma enter in the histologic differential diagnosis at this site. Therefore, the judicious use of a panel of selected immunostains is unquestionably helpful in diagnostically challenging cases. To find useful immunohistochemical markers for assisting in differential diagnosis between chordoma and other tumors with chordoid morphology, an immunohistochemical study using D2-40, epithelial membrane antigen (EMA), pan-cytokeratin (panCK), glial fibrillary acidic protein (GFAP), S-100 protein, galectin-3, neural cell adhesion molecule (NCAM), beta-catenin, E-cadherin, and carcinoembryonic antigen was performed on 14 chordomas, 7 chondrosarcomas, 9 myxopapillary ependymomas, and 4 chordoid meningiomas. Chordoma typically showed positive for EMA and panCK and negative for D2-40 and GFAP; whereas chondrosarcoma revealed positive for D2-40, and negative for EMA, panCK, and GFAP; myxopapillary ependymoma positive for GFAP and negative for EMA; and chordoid meningioma positive for EMA, and negative for panCK and GFAP. On the basis of our immunohistochemical study, a panel of D2-40, EMA, panCK, and GFAP allowed the correct recognition of all tumors examined. Other immunohistochemical markers including S-100 protein, galectin-3, NCAM, beta-catenin, E-cadherin, and carcinoembryonic antigen were of little value in differential diagnosis. In summary, the best immunohistochemical markers useful for the evaluation of tumors with chordoid morphology were D2-40, EMA, cytokeratin, and GFAP. D2-40 was a true chondroid marker to be useful for the differential diagnosis with chordoma.

Brachyury, SOX-9, and podoplanin, new markers in the skull base chordoma vs chondrosarcoma differential: a tissue microarray-based comparative analysis

The distinction between chondrosarcoma and chordoma of the skull base/head and neck is prognostically important; however, both have sufficient morphologic overlap to make delineation difficult. As a result of gene expression studies, additional candidate markers have been proposed to help in separating those entities. We sought to evaluate the performance of new markers: brachyury, SOX-9, and podoplanin alongside the more traditional markers glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen. Paraffin blocks from 103 skull base/head and neck chondroid tumors from 70 patients were retrieved (1969-2007). Diagnoses were made based on morphology and/or whole-section immunohistochemistry for cytokeratin and S100 protein yielding 79 chordomas (comprising 45 chondroid chordomas and 34 conventional chordomas), and 24 chondrosarcomas. A tissue microarray containing 0.6 mm cores of each tumor in triplicate was constructed using a manual array (MTA-1; Beecher Instruments). For visualization of staining, the ImmPRESS detection system (Vector Laboratories) with 2-diaminobenzidine substrate was used. Sensitivities and specificities were calculated for each marker. Core loss from the microarray ranged from 25 to 29% yielding 66-78 viable cases per stain. The classic marker, cytokeratin, still has the best performance characteristics. When combined with brachyury, accuracy improves slightly (sensitivity and specificity for detection of chordoma 98 and 100%, respectively). Positivity for both epithelial membrane antigen and AE1/AE3 had a sensitivity of 90% and a specificity of 100% for detecting chordoma in this study. SOX-9 is apparently common to both notochordal and cartilaginous differentiation, and is not useful in the chordoma-chondrosarcoma differential diagnosis. Glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen did not outperform other markers, and are less useful in the diagnosis of chordoma vs chondrosarcoma. Podoplanin still remains the only positive marker for chondrosarcoma, though its accuracy is less than previously reported.

A Case of Coccygeal Chondroid Chordoma in a Cat: Morphological and Immunohistochemical Features

In August 2007, a 4-year-old, intact, female Domestic Shorthair cat was examined for a mass on the tip of the tail. Histological examination performed after apical caudectomy revealed a neoplasm affecting the distal part of the last coccygeal vertebra. The neoplasm consisted of lobules of physaliferous cells surrounding cartilaginous tissue and a central core of trabecular bone. A diagnosis of chondroid chordoma was made based on histomorphological features and immunohistochemical results. Chondroid chordoma has been previously reported in humans, rats, ferrets, and mink. To the authors' knowledge, chondroid chordoma has not been reported in cats. Neither recurrence nor metastasis was reported 7 months after surgery.

Cervical Spinal Chordoma with Chondromatous Component in a Dog

A 7-year-old male Belgian Shepherd dog was presented with sudden onset of lateral recumbency and tetraparesis. At the level of the third cervical vertebra, magnetic resonance imaging demonstrated an intrameningeal and intramedullary mass lesion. The animal was subsequently euthanatized. A necropsy revealed a semitranslucent solid mass infiltrating dorsal and ventral dura mater and the spinal cord. Histologic examination revealed a lobulated pleomorphic mass, mainly resembling undifferentiated cartilage interspersed by spindle-shaped and polygonal cells with highly vacuolated cytoplasm (physaliphorous cells). Immunohistochemistry of the tumor cells demonstrated dual expression of vimentin and cytokeratin. Based on the histologic and immunohistochemical results, the diagnosis of a chordoma with chondromatous component was made.

Chordoma and chondrosarcoma gene profile: implications for immunotherapy

Chordoma and chondrosarcoma are malignant bone tumors characterized by the abundant production of extracellular matrix. The resistance of these tumors to conventional therapeutic modalities has prompted us to delineate the gene expression profile of these two tumor types, with the expectation to identify potential molecular therapeutic targets. Furthermore the transcriptional profile of chordomas and chrondrosarcomas was compared to a wide variety of sarcomas as well as to that of normal tissues of similar lineage, to determine whether they express unique gene signatures among other tumors of mesenchymal origin, and to identify changes associated with malignant transformation. A HG-U133A Affymetrix Chip platform was used to determine the gene expression signature in 6 chordoma and 14 chondrosarcoma lesions. Validation of selected genes was performed by qPCR and immunohistochemistry (IHC) on an extended subset of tumors. By unsupervised clustering, chordoma and chondrosarcoma tumors grouped together in a genomic cluster distinct from that of other sarcoma types. They shared overexpression of many extracellular matrix genes including aggrecan, type II & X collagen, fibronectin, matrillin 3, high molecular weight-melanoma associated antigen (HMW-MAA), matrix metalloproteinase MMP-9, and MMP-19. In contrast, T Brachyury and CD24 were selectively expressed in chordomas, as were Keratin 8,13,15,18 and 19. Chondrosarcomas are distinguished by high expression of type IX and XI collagen. Because of its potential usefulness as a target for immunotherapy, the expression of HMW-MAA was analyzed by IHC and was detected in 62% of chordomas and 48% of chondrosarcomas, respectively. Furthermore, western blotting analysis showed that HMW-MAA synthesized by chordoma cell lines has a structure similar to that of the antigen synthesized by melanoma cells. In conclusion, chordomas and chondrosarcomas share a similar gene expression profile of up-regulated extracellular matrix genes. HMW-MAA represents a potential useful target to apply immunotherapy to these tumors.

D2-40 functions as an effective chondroid marker distinguishing true chondroid tumors from chordoma

Chordomas and low-grade chondrosarcomas of the central nervous system share many histological features, generating, at times, considerable diagnostic difficulty and, not infrequently, requiring immunohistochemical analysis for appropriate classification. While both chordomas and chondrosarcomas stain positively for S100, only chordomas typically express epithelial antigens like cytokeratins and epithelial membrane antigen. Positive or negative staining with these latter two markers currently represents the only immunohistochemical technique that effectively distinguishes chordomas from chondrosarcomas. A marker that is reliably positive in chondrosarcomas and negative in chordomas has, to date, not been reported. D2-40 is a monoclonal antibody initially developed against M2A, a fetal testis-related antigen now known as podoplanin (aggrus), which has been found to stain a diverse collection of both benign and malignant tissues. In this study, we systematically investigated D2-40 immunoreactivity in a series of 22 chordomas, 20 chondrosarcomas, and 12 enchondromas, in conjunction with cytokeratin and S100 immunostaining. We found that D2-40 robustly and reliably immunostains low-grade chondroid neoplasms (100% of enchondromas and 94% of grades I and II chondrosarcomas), but not chordomas. By contrast, we observed generally strong and diffuse cytokeratin positivity in all cases of chordoma, but not in cases of enchondroma or low-grade chondrosarcoma. Thus, we show that D2-40 behaves as a chondroid marker differentiating true chondroid neoplasms from chordoma. We also demonstrate D2-40 immunoreactivity in two cases of chordoid meningioma and, in doing so, tentatively provide a means to distinguish this tumor from chordoma.

Brachyury, a crucial regulator of notochordal development, is a novel biomarker for chordomas

Chordomas are malignant tumours that occur along the spine and are thought to derive from notochordal remnants. There is significant morphological variability between and within chordomas, with some showing prominent areas of chondroid differentiation. Our microarray data from a broad range of connective tissue neoplasms indicate that, at the transcriptional level, chordomas resemble cartilaginous neoplasms. Here we show that chordomas express many genes known to be involved in cartilage development, but they also uniquely express genes distinguishing them from chondroid neoplasms. The brachyury transcription factor, known to be involved in notochordal development, is only expressed by chordomas. Using a polyclonal antibody, we show that brachyury is expressed in the embryonic notochord and in all 53 chordomas analysed, labelling both chondroid and chordoid areas of these tumours. In contrast, the protein was not detected in over 300 neoplasms, including 163 chondroid tumours. Brachyury was not detected in the nucleus pulposus, arguing against the hypothesis that this tissue derives directly from the notochord. These data provide compelling evidence that chordomas derive from notochord and demonstrate that brachyury is a specific marker for the notochord and notochord-derived tumours.

Recurrent and metastatic clivus chordoma: systemic palliative therapy retards disease progression

We report on a male patient with progressive and metastatic clivus chordoma treated over a period of 9 years by a multidisciplinary approach. Within the first 4 years, the patient underwent surgery four times. Thereafter, he received radiotherapy and subsequent chemotherapy. Stabilization of disease was achieved repeatedly for variable periods under local radiotherapy, systemic chemotherapy, immunomodulatory and anti-angiogenic therapy with isotretinoin and interferon-alpha, followed by thalidomide. Due to the occurrence of brain and lung metastases 8 years after initial diagnosis, liposomal doxorubicin was added to thalidomide. At the last follow-up control the patient had stable disease, with no progression of the intracranial tumor and regression of pulmonary metastases. He is in a good physical, psychological and neurological condition with a Karnofsky score of 80. Our observations show that multimodal therapy including a systemic palliative approach is associated with long quiescent intervals in recurrent chordoma and with regression of its metastases. Use of substances with high efficacy on tumor tissue and low toxicity, allowing long-term administration, seems promising in similar situations.

Chordoma: radiological-pathological correlation

This review correlates the imaging findings and histological appearances seen in chordomas in a series of patients presenting at our institution, together with a published literature review. A parallel presentation of photographs of imaging findings and microscopic histological findings is made, with the aim being to enhance recognition of this uncommon but clinically significant entity.

Skull base chordoma

PURPOSE

Our purpose was to discuss the optimal treatment and outcomes for patients with skull base chordomas.

METHODS

We reviewed the pertinent literature for this study.

RESULTS

Skull base chordomas usually arise in the clivus and are rarely completely resectable. Therefore, most are treated with radiotherapy (RT). Because of the risk of severe late complications, the dose is often limited with conventional photon RT, and the probability of cure is low. Proton RT alone or combined with photon RT (proton/photon RT) offers the advantage of improved dose distribution and the ability to treat the tumor to a higher dose without exceeding normal tissue tolerance. The 10-year local control rate after proton/photon RT is approximately 40% to 50%. The probability of local control is related to minimum tumor dose and dose inhomogeneity.

CONCLUSIONS

Skull base chordoma is a rare neoplasm that is rarely cured after surgery alone or combined with conventional RT. Proton/photon RT offers the advantage of increasing the tumor dose while minimizing the dose to normal tissues, thus reducing the risk of late complications. The optimal treatment may be photon/proton RT alone or combined with a gross total resection, when feasible.

Coccygeal chordoma in a dog

A 4-cm diameter spherical mass was removed from the region of the second coccygeal vertebra of a 6-year-old female Doberman Pinscher dog. The mass had been present for 7 months and was described as multilobular and smooth. Histologically, the neoplasm consisted of small spindle-shaped cells surrounding lobules of large vacuolated polygonal cells. Mucin was present within most lobules. The large polygonal cells stained positively with antibodies against vimentin, cytokeratin, and S-100 protein. Although the spindle-shaped cells stained positively with antibodies against vimentin, they only occasionally contained cytokeratin. The histology and immunohistochemistry are consistent with that reported for chordoma. Although 4 chordomas have previously been reported in dogs, this is the first case in which immunohistochemistry has been used to support the histological diagnosis. Neither recurrence nor metastasis was reported 10 months after surgical excision.

Chordoma in the sella turcica

A 75-year-old man presented with a rare case of chordoma in the sella turcica of the skull base. He had been treated for hypertension and chronic renal failure since 1990. Computed tomography detected a tumor in the sella turcica in 1994, but the patient had no clinical complaints and the serum pituitary hormone levels were normal. He died of disseminated intravascular coagulation, myocardial infarction, pulmonary infection, and multiple cerebral infarctions in 2000. At autopsy, the tumor in the sella turcica was 3.1 cm in greatest diameter and had compressed the pituitary gland posteriorly. Histological examination found oval cells and vacuolated short spindle-shaped cells which showed morphological changes similar to myxoma cells. The tumor was lobulated by narrow connective tissues. The tumor did not contain any cartilaginous tissue components, and was stained positively for epithelial membrane antigen but negatively for S-100 protein. The final diagnosis was chordoma. There was no association between the tumor and the cause of death.

A multidisciplinary team approach to skull base chordomas

OBJECT

A multidisciplinary team devised a protocol for long-term care of patients with skull base chordomas. In this study they describe their approach.

METHODS

Forty-two patients presented between 1986 and 1998 and were treated by maximum surgical cytoreduction and photon radiation therapy. Tumor volume-doubling time determined on the basis of magnetic resonance imaging, immunostaining, and cell proliferation (Ki67 labeling index [LI]) studies indicated growth rates of individual chordomas. The best outlook was associated with the greatest extent of tumor removal achieved during the first operation. There were no deaths associated with patients who underwent first-time surgery, but there was a 7.1% mortality rate associated with those who underwent subsequent operations. Cerebrospinal fluid leaks, additional cranial nerve palsies, and pharyngeal wound problems were the most difficult management problems encountered after second and subsequent surgeries. The time interval between operations was usually between 2 years and 3 years after the first surgery; very few patients required a second surgery, with a quiescent period in excess of 5 years. Life-table 5- and 10-year survival rates were 77% and 69%, respectively.

CONCLUSIONS

The authors believe that this series of skull base chordomas provides new insights into the management of these lesions, particularly with regard to techniques that increase survival times and studies that aid in formulating prognoses.

Skull base chordomas: correlation of tumour doubling time with age, mitosis and Ki67 proliferation index

The aim of the study was to assess the relationship between the rate of clinical tumour growth and various histological features, including Ki67 labelling index, in skull base chordoma. Cases of skull base chordoma from 19 patients (six female, 13 male; age range 8-63 years) were reviewed and the diagnosis confirmed based on histological and immunohistochemical features. In each biopsy cellularity, pleomorphism, mitotic activity, apoptotic bodies, necrosis and inflammatory cell infiltrate were graded and Ki67 labelling index (LI) calculated as a measure of proliferation. Tumour doubling time was assessed by quantitative analysis of tumour volumes in post-operative magnetic resonance images and correlated with age, sex, histological parameters and Ki67 LI. It was shown that increasing patient age, the presence of mitotic figures or a Ki67 LI in excess of 6% were associated with faster growing tumours.

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.

Keratin subsets and monoclonal antibody HBME-1 in chordoma: immunohistochemical differential diagnosis between tumors simulating chordoma

Thirty-five chordomas and more than 100 other tumors that have to be considered in the differential diagnosis, were immunohistochemically analyzed using a panel of antibodies including those to subsets of keratins (K), HBME-1, a monoclonal antibody recognizing an unknown antigen on mesothelial cells, and neuroendocrine markers. The patterns of immunoreactivities in chordoma were compared with those in renal cell carcinoma, colorectal mucinous adenocarcinoma, pituitary adenoma, skeletal chondrosarcoma, and extraskeletal myxoid chondrosarcoma (ESMC). Chordomas were consistently positive for keratin cocktail AE1/AE3, and for the individual keratins K8 and K19, and nearly always positive for K5, but they showed negative or only sporadic reactivity for K7 and K20. The keratin K8 and K19 reactivity was retained in those chordomas showing solid sheets of epithelioid, spindle cells, or cartilaginous metaplasia, and in one of two cases showing overtly sarcomatous transformation. In comparison, keratins were never present in skeletal chondrosarcoma, although K8 and to a lesser extent K19 were seen in occasional cases of ESMC with chordoid features. HBME-1 reacted strongly with chordoma and skeletal chondrosarcoma but was almost never positive in renal or colorectal carcinoma. These carcinomas lacked K5-reactivity, in contrast to chordoma. Chordomas were also consistently positive for neuron-specific enolase and occasionally focally for synaptophysin, but never for chromogranin. In contrast, pituitary adenomas regularly expressed the full spectrum of neuroendocrine markers and differed from chordoma by having a narrower repertoire of keratins, often showing negative or focal keratin 8- or AE1/AE3 reactivity and being almost always K19-negative. These findings indicate that chordoma can be immunohistochemically separated from tumors that can resemble it. Immunohistochemistry is especially useful in the diagnosis of small biopsy specimens that offer limited material for morphological observation.

Skull base chordomas: a management challenge

Because of their critical location, invasive nature, and aggressive recurrence, skull base chordomas are challenging and, at times, frustrating tumors to treat. Both radical surgical removal and high-dose radiation therapy, particularly proton beam therapy, reportedly are effective in tumor control and improve survival rates. The authors posit that these tumors are best treated with radical surgery and proton-photon beam therapy. During the last 5 years, they treated 25 patients (15 females and 10 males) who harbored pathologically diagnosed skull base chordomas. The mean age of the patients was 38.4 years (range 8-61 years). Previous surgery or radiation therapy was performed at other institutions in seven and two patients, respectively. The authors performed 33 surgical procedures on 23 patients. Radical removal (defined as absence of residual tumor on operative inspection and postoperative imaging) was achieved in 10 patients; subtotal resection (defined as resection of > 90% of the tumor) was achieved in 11 patients; and partial resection (defined as resection of < 90% of the tumor) was achieved in two patients. Radical surgical removal included not only the excision of soft-tumor tissue, but also extensive drilling of the adjacent bone. Adjuvant therapy consisted of postoperative combined proton-photon beam therapy (given to 17 patients and planned for one patient) and conventional radiation therapy (two patients); three patients received no adjunct therapy. To date, four patients have died. One patient who had undergone previous surgery and sacrifice of the internal carotid artery died postoperatively from a massive stroke; one patient died from adenocarcinoma of the pancreas without evidence of recurrence; and two patients died at 25 and 39 months of recurrent tumor. Permanent neurological complications included third cranial nerve palsy (one patient) and hemianopsia (one patient); radiation necrosis occurred in three patients. Of the 21 patients followed for more than 3 months after surgery, 16 have had no evidence of recurrence and five (including the two mortalities noted above) have had recurrent tumors (four diagnosed clinically and one radiologically). The mean disease-free interval was 14.4 months. A longer follow-up period will, hopefully, support the early indication that radical surgical removal and postoperative proton-photon beam therapy is an efficacious treatment. The use of skull base approaches based on the tumor classification introduced in this paper is associated with low mortality and morbidity rates.