Immunohistochemical investigation of chordomas: histogenetic and differential diagnostic aspects

Endoscopic Endonasal Management of Skull Base Chordomas: Surgical Technique, Nuances, and Pitfalls

Chordoma is a rare primary bone tumor derived from transformed notochord remnants. It has a local aggressive behavior and high recurrence rates. Treatment of skull base chordomas is complex and challenging. Control of the disease relies mainly on surgical excision of the tumor, sometimes followed by high-dose radiation therapy. The main surgical goal is to achieve maximal tumor removal with minimal morbidity. Development of the expanded endoscopic endonasal approach has improved surgical and prognostic results of skull base chordomas. This article highlights important aspects of approach selection, technique, and nuances of surgical management of this tumor.

IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING AND HISTOPATHOLOGICAL FEATURES OF A SKULL BASE CHORDOMA IN A CAT

An 8-year-old domestic short-haired cat was presented with anorexia, lethargy, ataxia and one episode of consciousness loss. A midline vertically orientated, biconcave, extra-axial mass originating from the basioccipital bone was detected on magnetic resonance images of the head. The mass was T1W iso- to hypointense when compared with normal grey matter, T2W hyperintense with small areas of isointensity and heterogeneously enhanced with contrast. Multiple signal voids were observed on T2^* images. Histopathological evaluation confirmed a chordoma. To the authors' knowledge this is the first report of the imaging characteristics of a chordoma affecting the skull base in a cat.

Three-dimensional endoscopy in transnasal transsphenoidal approach to clival chordomas

BACKGROUND

The purpose of this prospective, observational study was to evaluate the management of skull base chordomas surgically resected via a 3D-endoscopic transnasal approach.

METHODS

Thirteen consecutive patients were observed and only 9 were surgically treated using a 3D-endoscopic transnasal approach assisted by a novel 3D visualization system.

RESULTS

Nine consecutive male patients (mean age, 57.4 years) underwent exclusive 3D-endoscopic transnasal transsphenoidal resection of clival chordomas; gross total resection was achieved in 66.6% of cases (6 of 9 patients), near-total resection in 11.2% (1 of 9 patients), and partial resection in 22.2% (2 of 9 patients). The complications observed were 2 cases of postoperative cerebrospinal fluid (CSF) leaks and 1 case of temporary VI cranial nerve palsy.

CONCLUSION

No discomfort was recorded; when a dura opening was required, 3D vision allowed an accurate intradural sharp dissection and a precise repair of the skull base. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1814-E1819, 2016.

The expanding role of the endonasal endoscopic approach in pituitary and skull base surgery: A 2014 perspective

BACKGROUND

The past two decades have been the setting for remarkable advancement in endonasal endoscopic neurosurgery. Refinements in camera definition, surgical instrumentation, navigation, and surgical technique, including the dual surgeon team, have facilitated purely endonasal endoscopic approaches to the majority of the midline skull base that were previously difficult to access through the transsphenoidal microscopic approach.

METHODS

This review article looks at many of the articles from 2011 to 2014 citing endonasal endoscopic surgery with regard to approaches and reconstructive techniques, pathologies treated and outcomes, and new technologies under consideration.

RESULTS

Refinements in approach and closure techniques have reduced the risk of cerebrospinal fluid leak and infection. This has allowed surgeons to more aggressively treat a variety of pathologies. Four main pathologies with outcomes after treatment were identified for discussion: pituitary adenomas, craniopharyngiomas, anterior skull base meningiomas, and chordomas. Within all four of these tumor types, articles have demonstrated the efficacy, and in certain cases, the advantages over more traditional microscope-based techniques, of the endonasal endoscopic technique.

CONCLUSIONS

The endonasal endoscopic approach is a necessary tool in the modern skull base surgeon's armamentarium. Its efficacy for treatment of a wide variety of skull base pathologies has been repeatedly demonstrated. In the experienced surgeon's hands, this technique may offer the advantage of greater tumor removal with reduced overall complications over traditional craniotomies for select tumor pathologies centered near the midline skull base.

Endoscopic endonasal approach in the management of skull base chordomas--clinical experience on a large series, technique, outcome, and pitfalls

Skull base chordomas represent very interesting neoplasms, due to their rarity, biological behavior, and resistance to treatment. Their management is very challenging. Recently, the use of a natural corridor, through the nose and the sphenoid sinus, improved morbidity and mortality allowing also for excellent removal rates. Prospective analysis of 54 patients harboring a skull base chordoma that were managed by extended endonasal endoscopic approach (EEA). Among the 54 patients treated (during a 72 months period), 21 were women and 33 men, undergoing 58 procedures. Twenty-two cases (40%) were recurrent and 32 (60%) newly diagnosed chordomas. Among the 32 newly diagnosed chordomas, a gross total resection was achieved in 28 cases (88%), a near total (>95% of tumor) in 2 cases (6%), a partial (>50% of tumor) in 2 cases (6%). Among the 22 recurrent chordomas, resection was complete in 7 cases (30%), near total in 7 (30%), and partial in 8 (40%). The global gross total resection rate was 65% (35/54 cases). Four patients (11%) recurred and 4 (11%) progressed within a mean follow-up of 34 months (range 12-84 months). Four patients (11%) were re-operated; one patient (1.8%) died due to disease progression, one patient (1.8%) died 2 weeks after surgery due to a massive bleeding from an ICA pseudo aneurysm. CSF leakage occurred in four patients (8%), and meningitis in eight cases (14%). No new permanent neurological deficit occurred. The EEA management of skull base chordomas requires a long and gradual learning curve that once acquired offers the possibility of either similar or better resection rates as compared to traditional approaches while morbidity is improved.

ENDOSCOPIC ENDONASAL APPROACH FOR CLIVAL CHORDOMAS

OBJECTIVE

Cranial base chordomas are difficult lesions to treat. The endoscopic endonasal approach (EEA) takes advantage of the natural sinus corridor and may provide a less invasive approach for these midline tumors.

METHODS

Patients undergoing EEA for chordomas were selected from a database of more than 800 consecutive patients undergoing EEA at the University of Pittsburgh Medical Center and were retrospectively evaluated. Additionally, a systematic review of the literature of endoscopic endonasally resected chordomas was performed and compared with our personal experience.

RESULTS

Twenty patients (8 females and 12 males) underwent 26 endoscopic EEAs for cranial base chordomas. Eight chordomas (40%) were recurrent. Treatment of the 12 newly diagnosed chordomas included 8 total resections (66.7%), 2 near total resections (16.7%), and 2 subtotal resections (16.7%). Treatment of the 8 recurrent chordomas included 1 gross total resection (12.5%), 2 near total resections (25.0%), and 5 subtotal resections (62.5%). Two patients (10%) had recurrences, and 5 patients (25%) progressed during the mean follow-up period of 13 months (range, 1–45 months). Five patients (25%) underwent re-resection, 1 patient was lost to follow-up, and 1 patient died secondary to progression of disease. There was 1 intraoperative vascular complication with no sequelae. The cerebrospinal fluid leak rate was 25%, and there were no cases of bacterial meningitis. The incidence of a new permanent neurological complication was 5%. A systematic review of the literature yielded a total of 26 cases of chordomas resected via a completely endoscopic endonasal technique.

CONCLUSION

Endoscopic endonasal resection of cranial base chordomas is safe once adequate experience is gained with the technique. This approach provides the potential for, at the least, similar resections compared with traditional cranial base approaches while potentially limiting morbidity.

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.

The endoscopic transnasal transsphenoidal approach for the treatment of cranial base chordomas and chondrosarcomas

OBJECTIVE

We report our experience with endoscopic transsphenoidal or extended endoscopic transsphenoidal approaches for the treatment of cranial base lesions such as clival chordomas and chondrosarcomas.

METHODS

Between May 1998 and April 2004, 11 patients (four were recurrences because they previously had been treated with surgery and/or radiotherapy) underwent transnasal transsphenoidal endoscopic surgery for cranial base chordomas and chondrosarcomas at the Neurosurgical Department of Bellaria Hospital in Bologna. The transsphenoidal endoscopic approach and the ethmoid-pterygo-sphenoidal endoscopic approach were used to accomplish resection of the lesions involving the clivus and extending up to the parasellar region and to the petrous apex, or within the cavernous sinus.

RESULTS

Patient follow-up periods ranged from 15 to 69 months (mean, 27 mo). Three patients died of chordoma progression at 20, 14, and 10 months, respectively, after endoscopic treatment. One patient experienced two recurrences; the first was treated using a new endoscopic approach, whereas the second, 1 year later, was treated by means of a far lateral approach. Four patients underwent postoperative proton beam radiotherapy, whereas one underwent a conventional megavoltage x-radiation therapy. However, postoperative radiotherapy was not administered in the two patients treated for cranial base chondrosarcoma.

CONCLUSION

The flexibility of this new technique with respect to the classical microscopic transsphenoidal approach permits us to widen the horizon of surgical management of aggressive cranial base tumors such as clival chordomas and chondrosarcomas.

Update on the cytogenetics and molecular genetics of chordoma

Chordoma is a rare mesenchymal tumour of complex biology for which only histologic and immunohistochemical criteria have been defined, but no biomarkers predicting the clinical outcome and response to treatment have yet been recognised. We herein review the interdisciplinary information achieved by epidemiologists, neurosurgeons and basic scientists on chordoma, usually a sporadic tumour, which also includes a small fraction of familial cases. Main focus is on the current knowledge of the genetic alterations which might pinpoint candidate genes and molecular mechanisms shared by sporadic and familiar chordomas. Due to the scarcity of the investigated tumour specimens and the multiple chromosome abnormalities found in tumours with aberrant karyotypes, conventional cytogenetics and Fluorescence In Situ Hybridization failed to detect recurrent chordoma-specific chromosomal rearrangements. Genome-wide approaches such as Comparative Genomic Hybridization (CGH) are yet at an initial stage of application and should be implemented using BAC arrays either genome-wide or targeting selected genomic regions, disclosed by Loss of Heterozygosity (LOH) studies. An LOH region was shown by a systematic study on a consistent number of chordomas to encompass 1p36, a genomic interval where a candidate gene was suggested to reside. Despite the rarity of multiplex families with chordoma impaired linkage studies, a chordoma locus could be mapped to chromosome 7q33 by positive lod score in three independent families. The role in chordomagenesis of the Tuberous Sclerosis Complex (TSC) genes has been proved, but the extent of involvement of TSC1 and TSC2 oncosuppressors in chordoma remains to be assessed. In spite of the scarce knowledge on the genetics and molecular biology of chordoma, recent initiation of clinical trials using molecular-targeted therapy, should validate new molecular targets and predict the efficacy of a given therapy. Comparative genetic and biomolecular studies should enhance the molecular taxonomy of chordoma which might have a prognostic significance and better orient the therapeutic options.

Parachordoma or chordoma periphericum? Case report of a tumor of the thoracic wall

We report the findings from an aspiration biopsy and resection of a chordoma-like tumorous mass in the wall of the thorax of a 36-yr-old man with immunohistochemical, ultrastructural, and cytogenetic studies. The 4-cm oval tumor was an incidental finding on physical examination, and no other lesions were identified after comprehensive radiologic studies. The aspirate was composed of sheets and nests of cells with distinct borders in a myxoid and fibrillary extracellular matrix. The neoplastic cells were uniform and round or polygonal with abundant pale blue vacuolated cytoplasm and small round, central or eccentric nuclei. On electron microscopy, mitochondrial rough endoplasmic reticulum complexes were seen in neoplastic cells. These features were similar to those of a conventional chordoma. However, the cytogenetic pattern, 43, XY ,-1, -2, der (5)t(1p;5q), -6, add(8p) ,add(10q), was not typical. In addition, the neoplastic cells were positive for vimentin, S-100, AE1/AE3, CAM 5.2, and CK 19; were focally positive for EMA and smooth muscle actin; and were negative for cytokeratin 1 and 10 (34 beta E12), CK 7, CK 8 (35H 11B), CK 17, and CK 20. The cytogenetic and immunohistochemical patterns were different from conventional chordoma and its peripheral counterpart, chordoma periphericum, suggesting the diagnosis of parachordoma. To the best of our knowledge, this is the first report of fine-needle aspiration of this newly defined and rare entity.

Giant vertebral notochordal rest: a lesion distinct from chordoma: discussion of an evolving concept

A 14-year-old boy with severe back pain for several years is described. Roentgenograms, bone scans, and computed tomographic scans of the spine were normal, but magnetic resonance imaging studies showed a lumbar vertebral body lesion, confined to the bone, with low T1- and high T2-weighted signal intensities. Histologically, the lesion consisted of sheet-like notochordal-type tissue, containing physaliphorous cells but lacking the usual features of chordoma. A diagnosis of giant notochordal rest was made. A review of prior possible examples of this recently described and controversial entity is made with a discussion of its embryologic foundations and distinction from chordoma.

Stereotactic fractionated radiotherapy for chordomas and chondrosarcomas of the skull base

PURPOSE

To investigate the treatment outcome of patients suffering from skull base chordoma or chondrosarcoma after fractionated stereotactic radiotherapy.

METHODS AND MATERIALS

We report 45 patients treated for chordoma or chondrosarcoma with postoperative fractionated stereotactic radiotherapy between 1990 and 1997. Patients had CT and MRI for 3D treatment planning performed under stereotactic guidance. Median dose at isocenter was 66.6 Gy for chordomas and 64.9 Gy for chondrosarcomas. MRI imaging was obtained in intervals after therapy to evaluate local relapse. Survival was calculated according to the Kaplan-Meier method.

RESULTS

All chondrosarcomas had achieved and maintained local control and recurrence-free status at follow-up of 5 years. Local control rate of chordomas was 82% at 2 years and 50% at 5 years. Survival was 97% at 2 years and 82% at 5 years. At maximum follow-up of 8 years local control and survival rate of chordomas was 40% (82%). Clinically significant late toxicity developed in one patient.

CONCLUSIONS

Our results demonstrate the feasibility of fractionated photon beam therapy and its success in the treatment of skull base tumors. Modern 3D treatment techniques provide superior results compared to conventional techniques. The role of high-precision radiotherapy compared to particle beam therapy in the treatment of these tumors is not yet fully clear and further research is needed.

Stereotactic radiosurgery for chordoma and chondrosarcoma: further experiences

PURPOSE

Skull base chordomas and chondrosarcomas pose management challenges owing to their critical location, locally aggressive nature, and high recurrence rate despite multimodality treatment. We used stereotactic radiosurgery as primary or adjuvant therapy to achieve safe and effective therapeutic irradiation.

METHODS AND MATERIALS

At an average of 4 years (range 1-7), we evaluated 15 patients (nine with chordomas and six with chondrosarcomas) who had gamma-knife radiosurgery as an adjunct (13 patients) or as an alternative to microsurgical resection (two patients). Patient age varied from 7 to 70 years (mean 38). There was a distinct male preponderance (2:1). Thirteen patients had undergone between one and four resections. Using conformal radiosurgical planning, a maximum tumor dose of 24-40 Gy (mean 36) and a tumor margin dose of 12-20 Gy (mean 18) was given to a mean tumor volume of 4.6 ml.

RESULTS

Eight patients showed clinical improvement, three remained stable, and four died. Two of the four patients who died had tumor progression remote from the radiosurgery volume; two patients died of unrelated disorders. Among 11 surviving patients, follow-up imaging showed a reduction in tumor size in five, no further tumor growth in five, and an increase in the size of the tumor in one. The patient with further tumor growth after radiosurgery subsequently underwent repeat resection.

CONCLUSION

Despite the formidable management challenge posed by these neoplasms, our long-term evaluation has shown that radiosurgery is a safe and effective treatment for patients with small volume tumors.

Detection and distribution of the carbohydrate binding protein galectin-3 in human notochord, intervertebral disc and chordoma

Galectin-3 is an endogenous carbohydrate-binding protein which plays a role in cell differentiation, morphogenesis and cancer biology. We investigated the occurrence and distribution of galectin-3 in the embryonic and fetal human notochord, the developing human vertebral column, adult intervertebral discs and in six chordomas, which are tumors thought to originate from notochordal remnants. By means of Western blots, the expression of galectin-3 was confirmed in tissue probes from the vertebral column region beginning with the 8th gestational week. These results were supported by immunohistochemical data which revealed the presence of galectin-3 in the cytoplasm of cells of the notochord also from the 8th gestational week onwards. Notochordal immunostaining became stronger with increasing gestational age. A persisting notochordal remnant in an adult intervertebral disc and various cells of the nucleus pulposus also contained galectin-3. All chordomas showed moderate or strong immunoreactivity irrespective of their cellular composition. Subcellularly, galectin-3 was localized mostly in the cytoplasm, while a subset of tumor cells also showed nuclear distribution. Differences in staining patterns of chordoma cells could not, in general, be correlated to any histological features of these tumors.

Chordomas and chondrosarcomas of the cranial base: results and follow-up of 60 patients

The management of chordomas and chondrosarcomas involving the cranial base remains controversial. The options for therapy include biopsy, partial resection, radical resection, and various forms of radiotherapy. In this article, we analyze the outcome of 60 patients with cranial base chordoma or chondrosarcoma treated with extensive surgical resection between 1984 and 1993. Forty-six patients had chordomas, and 14 had low-grade chondrosarcomas; 50% of these patients had been treated previously. Preoperative studies included computed tomography, magnetic resonance imaging, cerebral angiography, and balloon occlusion test of the internal carotid artery, as indicated. Magnetic resonance imaging was performed on all patients during follow-up. The surgical approaches used for tumor resection were predominantly the following: subtemporal, transzygomatic, transcavernous, and transpetrous apex; subtemporal and infratemporal; extended frontal; and extreme lateral transcondylar. Staged operations with a combination of approaches were used when necessary (52% of cases) to remove a tumor more completely. Statistical analysis was done by the chi 2 test and correlation matrix. Sixty-seven percent of the patients had total or near-total resection. Twenty percent of the patients received postoperative radiotherapy. Eleven patients died during the postoperative follow-up period, nine with chordomas and two with chondrosarcomas. Three patients died because of systemic complications within 3 months after surgery, five died because of tumor recurrence, one died from unrelated causes, and two died from late complications of radiotherapy. The recurrence-free survival rate for all tumors was 80% at 3 years and 76% at 5 years. Chondrosarcomas had a better prognosis than chordomas (recurrence-free survival rates, 90% at 5 years and 65% at 5 years, respectively; P = 0.09). Patients who had undergone previous surgery had a greater risk of recurrence (5-year recurrence-free survival rate, 64%) than did patients who had not undergone previous surgery (5-year recurrence-free survival rate, 93%; P < 0.05). Patients with total or near-total resection had a better 5-year recurrence-free survival rate (84%) than did patients with partial or subtotal resection (64%) (P < 0.05). Postoperative leakage of cerebrospinal fluid was the most frequent complication (30% of patients) and was found to increase the risk of permanent disability. Patients who had undergone previous radiotherapy had a greater risk of death in the postoperative period (within 3 months of their operations) and during follow-up. However, total or near-total resection did not increase the rate of postoperative disability.(ABSTRACT TRUNCATED AT 400 WORDS)

Intermediate filament typing of the human embryonic and fetal notochord

In order to characterize human notochordal tissue we investigated notochords from 32 human embryos and fetuses ranging between the 5th and 13th gestational week, using immunohistochemistry to detect intermediate filament proteins cytokeratin, vimentin and desmin, the cytokeratin subtypes 7, 8, 18, 19 and 20, epithelial membrane antigen (EMA), and adhesion molecules pan-cadherin and E-cadherin. Strong immunoreactions could be demonstrated for pan-cytokeratin, but not for desmin or EMA. Staining for pan-cadherin and weak staining for E-cadherin was found on cell membranes of notochordal cells. Also it was demonstrated that notochordal cells of all developmental stages contain the cytokeratins 8, 18 and 19, but not 7 or 20. Some cells in the embryonic notochord also contained some vimentin. Vimentin reactivity increased between the 8th and 13th gestational week parallel to morphological changes leading from an epithelial phenotype to the chorda reticulum which represents a mesenchymal tissue within the intervertebral disc anlagen. This coexpression reflects the epithelial-mesenchymal transformation of the notochord, which also loses E-cadherin expression during later stages. Our findings cannot elucidate a histogenetic germ layer origin of the human notochord but demonstrate its epithelial character. Thus, morphogenetic inductive processes between the human notochord and its surrounding vertebral column anlagen can be classified as epithelial-mesenchymal interactions.

Myasthenia gravis in a man with a history of chordoma: Observations of muscle-like antigens in chordoma

A 67-year-old white man with a remote history of a chordoma of the clivus presented with myasthenia gravis. We investigated the possibility that these conditions were related immunologically. Tissue sections of various chordoma specimens were reacted with dilutions of patient serum and control serum by an indirect immunoperoxidase method. In addition, sections were reacted with antibodies to muscle antigens. Of six chordomas, five reacted positively to patient serum. None reacted to control serum. One chordoma reacted positively to desmin, and all six reacted positively to myoglobin. We propose that the patient may have produced antibody to muscle-like antigens of the chordoma that subsequently cross-reacted with acetylcholine receptor and led to clinical myasthenia gravis.

Chordoma of the mobile spine. A clinicopathologic analysis of 40 patients

BACKGROUND

Chordomas are lobulated neoplasms composed of physaliphorous cells and their precursors; some have atypical, epithelioid, or spindle cell features. Fewer than one-sixth of chordomas arise in the mobile (cervical, thoracic, or lumbar) spine. Forty-eight percent originate in the sacrococcygeal region and 39% in the sphenoocciput.

METHODS

The study included 40 patients, 27 men and 13 women (2:1), with chordoma of the mobile spine. Their clinical and histopathologic features are described.

RESULTS

Nineteen tumors (48%) were located in the cervical spine, 7 (17%) in the thoracic spine, and 14 (35%) in the lumbar area. Most patients underwent subtotal removal of the tumor and postoperative irradiation. Variations in histologic appearance, including an occasional chondroid background, did not affect biologic behavior. Twenty-three patients (58%) were alive 5 years after surgery. Eventually, 25 patients (63%) died of tumor. Metastasis developed in two patients (5%). In contrast to some other studies metastasis was a rare occurrence.

CONCLUSION

Chordoma of the mobile spine is a slow-growing, recurring neoplasm of low metastatic potential that incapacitates by locally aggressive growth.

Chordoma involving the skin: an immunohistochemical study of 11 cases

Immunohistochemical properties were studied in 16 lesions from 11 patients with chordoma involving the skin. There were nine men and two women ranging from 21 to 62 years old (mean, 42.6). The initial tumor was sacrococcygeal in 10 cases and nasopharyngeal in 1 case. Three lesions represented a direct extension from the primary tumor to the skin, and 13 lesions were examples of local recurrences in the skin. Immunohistochemically, all lesions showed positivity for keratin, whereas 14 lesions were positive for vimentin and 12 for protein S-100. Epithelial membrane antigen was positive in four instances and carcinoembryonic antigen was negative in all studies. No significant difference was observed between the immunoprofile of cases of direct extension and those of local recurrences. Overall, the remarkable triple positivity for keratin, vimentin, and protein S-100 was observed in 11 lesions from eight different cases (73%). This study confirmed the utility of immunohistochemistry in the differential diagnosis of chordoma from tumors with similar histologic characteristics encountered in the skin.

Expression of intermediate filaments in chordomas. An immunocytochemical study of five cases

An immunocytochemical investigation has been carried out on five cases of chordoma (2 of the sacrum, 2 in the spheno-occipital bone and 1 in the parapharyngeal area) to study the expression of the 5 classes of intermediate filaments (IF): cytokeratin (CK), desmin (DES), GFAP, neurofilaments (NF) and vimentin (VIM). Our results show that constant coexpression of CK, NF and VIM does occur in chordomas, whereas DES and GFAP are not demonstrable in tumor cells. The three detected IF are invariably present in all cell types but not in intracellular vacuoles or in the extracellular mucoid substance. The pattern of immunoreactivity of chordomas appears very unique as very few other neoplasms demonstrate the simultaneous occurrence of 3 distinct IF. Only choroid plexus tumors have been shown to manifest CK-NF-VIM immunoreactivity. The complex immunophenotype of chordomas may be related to their supposed origin from the notochord which normally undergoes conspicuous changes in location and morphology during embryonal development. Such changes might require the contemporary presence of multiple IF; IF expression, in fact, is known to be related to cell function and morphology. Notochordal cells and their neoplastic counterpart may consequently express an IF pattern which reflects unique architectural and morphological variations occurring during embryonal and tumor growth. Together with the speculative value of the detection of CK, NF and VIM in chordomas, the unusual immunocytochemical pattern of these tumors might provide useful diagnostic tool in differential diagnosis.

Sarcomatous transformation in cranial chordoma

In a study of 52 patients with cranial chordoma treated at the Mayo Clinic over a 19-year period (1966-1984), two tumors showed anaplastic features, both de novo, i.e., unassociated with prior irradiation. The incidence of anaplastic transformation was thus 4%. Immunohistochemistry showed the mixed mesenchymal-epithelial phenotype typical of chordoma in portions of both tumors, but loss of reactivity for keratin and epithelial membrane antigen was noted in anaplastic components. The study indicates that sarcomatous change in chordoma is a rare event that may occur de novo and is associated with the loss of immunophenotypic features of epithelial differentiation.

Chondroblastoma of bone. A clinical, radiological, light and immunohistochemical study

The clinical and morphological findings of 53 chondroblastomas in the files of the Bone Tumour Registry of Westphalia are presented. The mean age of all patients was 19.2 years. The male-to-female ratio was 1.5:1. Forty-two of the tumours (79.8%) were located in the long tubular bones and short tubular bones of the hands and were closely related to the growth plate. Six cases (11.3%) were found in the flat bones, 4 cases (7.5%) in the tarsal bones and 1 case (1.9%) in the craniofacial bones. The characteristic radiological feature of 44 investigated lesions was a mostly eccentric radiolucency with a geographic pattern of bone destruction and matrix calcifications. Periosteal reaction was evident in 9% of the cases. Most tumours demonstrate the typical morphological features of chondroblastoma, but 3 cases resembled a giant cell tumour. In 2 cases a haemangiopericytoma-like growth pattern was observed. Nine of the tumours had an aneurysmal bone cyst-like component. Vascular invasion was seen in 1 case. Immunohistochemically most cells in 30 of the cases and fetal chondroblasts in 3 cases were strongly positive with vimentin and S-100 protein. Collagen type II was positive in the chondroid matrix of the tumours and in fetal cartilage tissue; collagen type VI was present focally around individual tumour cells and was always seen in the chondroid matrix of the lesions and in fetal cartilage. These findings support the cartilaginous nature of these tumours. In paraffin sections, 46.6% of the cases revealed a distinct positive reaction of some tumour cells with the monoclonal cytokeratin antibody KL1 (molecular weight 55-57 kDa). Only 4 of them demonstrated a coexpression with the other monoclonal cytokeratin antibody CK (clone MNF 116, molecular weight 45-56.5 kDa). In paraffin sections all fetal chondroblasts were negative with both cytokeratin antibodies. Frozen sections of 3 tumours showed a strong positive reaction with both cytokeratin antibodies in many chondroblasts, indicating an "aberrant" cytokeratin expression. Osteoclast-like giant cells stained positive with leucocyte-common antigen (LCA) and with the macrophage-associated antibody KP1, but were negative with the other macrophage-associated antibody MAC 387. Recurrence rate was 10.7%. The clinical course of all tumours was benign.

Chromosomal abnormalities in two chordomas

Cytogenetic analyses of two sacral chordomas are reported. Both tumors showed clonal chromosome abnormalities, including numerical and structural aberrations. The modal chromosome numbers were 36 and 72, respectively. The hypodiploid tumor had a single structural abnormality identified as a der(21)t(1;21)(q21;q22). The near-triploid tumor had numerous structural rearrangements, including a der(21)t(2;21)(q11;q22), which involves the same band of chromosome 21 as the translocation in the first tumor. Prophasing was a prominent cytogenetic feature of this tumor. The consistent involvement of band 21q22 in translocations in two chordomas suggests a possible specific association of this chromosome region with chordoma. Protooncogenes ETS2 and ERG have been mapped to this chromosome band.

Cellular variant of extraskeletal myxoid chondrosarcoma of abdominal wall--a case report with comparative immunohistochemical study on cartilaginous collagenous proteins in various myxoid mesenchymal tumors

A rare cellular variant of recurrent extraskeletal myxoid chondrosarcoma occurring in the right lower abdominal wall of a 70-year-old man, is presented with emphasis on a characteristic distribution pattern of cartilaginous collagen proteins in the stroma. While the primary and the first recurrent tumors showed the typical histology of extraskeletal myxoid chondrosarcoma, the later tumor, which recurred 14 years after the first resection, comprised mostly compact nodules of proliferating anaplastic cells with little mucoid stroma. Some areas presented a hemangiopericytomatous pattern. A few nodules possessed abundant myxoid stroma. Immunohistochemically, type II collagen was demonstrated in the stroma of some cellular areas, and type VI collagen was intensely stained around individual tumor cells both in cellular and myxoid areas. In a comparative immunohistochemical study, the same distribution pattern of cartilaginous collagen proteins was observed only in skeletal myxoid chondrosarcomas, but not in other mesenchymal tumors with abundant myxoid stroma. These findings seem to support the cartilaginous nature of extraskeletal myxoid chondrosarcoma, and will facilitate the differential diagnosis of soft-tissue tumors with myxoid stroma.

A histomorphologic and immunohistochemical study of chordoma in twenty ferrets (Mustela putorius furo)

The histomorphologic and immunohistochemical features of chordoma in 20 ferrets were evaluated. The mean age was 3.4 years, and, in the cases for which sex was known, females (n = 10) outnumbered males (n = 5) two to one. All 20 tumors occurred on the tip of the tail. Nineteen of 20 tumors (95%) were composed of three tissue components, often arranged concentrically with lobules of physaliferous cells at the periphery, trabecular bone in the center, and cartilage in between. The bone often contained marrow and hematopoietic cells. One tumor lacked chondromatous or osseous tissue. Immunohistochemical results were consistent with previous studies of chordoma. All 20 tumors (100%) were positive for keratin and vimentin intermediate filaments; 15 (75%) were positive for S-100 protein; and 17 (85%) were positive for neuron specific enolase. This neoplasm shares morphologic and immunohistochemical features with "classic," as well as chondroid chordoma, of human beings, making it a potential animal model.

Classical and chondroid chordoma. A light-microscopic, histochemical, ultrastructural and immunohistochemical analysis of the various cell types

The aim of the present investigation was to characterize the various cell types of classical and chondroid chordomas. Eight cases of classical chordoma, 1 case of sacrococcygeal chordoma with chondroid areas and 2 cases of spheno-occipital chondroid chordoma were studied. Ultrastructurally and immunohistochemically (immunoreactivity for cytokeratins, epithelial membrane antigen [EMA], tissue polypeptide antigen [TPA] and human milk fat globule protein [HMFG]) the 3 cell types (physaliferous, epithelial-like, and spindle-shaped) recognized light-microscopically presented features of epithelial differentiation and rather formed a continuous spectrum than being distinct cell types. The chondroid areas of the chondroid chordomas had similar ultrastructural and immunohistochemical properties except for the lack of immunoreactivity for EMA and HMFG. The results of the critical electrolyte concentration technique according to Scott and Dorling indicated that there was no difference in the sulfated glycosaminoglycan content between classical and chondroid chordomas: all the tumors contained chondroitin sulfate. The presence of chondroitin sulfate, immunoreactivity for vimentin and S-100 protein and areas of cartilaginous differentiation in three cases indicate a relationship both to chondromatous tumors and to normal notochord, from which chordoma is believed to originate.

Fine-needle aspiration cytology of an unusual primary lung tumor, chondrosarcoma: case report

A case of primary chondrosarcoma of the lung diagnosed by fine-needle aspiration biopsy (FNAB) cytology in a 78-yr-old male is presented. A mass detected on chest x-ray and defined by CT scan was subjected to a preoperative percutaneous fine-needle aspiration under fluoroscopic guidance. The distinctive cytologic features of pleomorphic cells nestled in lacunae surrounded by a chondromyxoid background resulted in a diagnosis of chondrosarcoma. The left upper lobectomy specimen confirmed the FNAB diagnosis and identified the tumor as arising from the left upper lobe bronchus.

Microtubular aggregates in the rough endoplasmic reticulum of sacrococcygeal chordoma

A tumor with the light microscopic and immunohistologic characteristics of chordoma in the sacrococcygeal region in a 48-year-old man was examined by electron microscopy and immunohistochemistry for tubulin. A large population of cells exhibited prominent parallel arrays of long, straight microtubules in the rough endoplasmic reticulum in addition to the well-described ultrastructural features of chordoma. Immunoreaction to tubulin recognized in the juxtanuclear regions of the large number of tumor cells was in accordance with the ultrastructural localization of the microtubular aggregates. This seems to be the first report of microtubular aggregations in rough endoplasmic reticulum in classic chordoma. Furthermore, the present electron microscopic and immunohistochemical findings suggest that tubulin is a constituent of the unusual structures.