Clinicopathological features with outcomes of a series of conventional and proximal-type epithelioid sarcomas, diagnosed over a period of 10 years at a tertiary cancer hospital in India

Prognostic nomogram in patients with epithelioid sarcoma: A SEER-based study

OBJECTIVE

The prognostic factors for patients with epithelial sarcoma remain unclear. The study aims to develop a practical clinical nomogram that predicts prognosis in patients with ES using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

We extracted clinical data from 2004 to 2015 from the SEER database about patients with ES. All patients were randomly divided into training cohort and validation cohort. Kaplan-Meier analyses were used to compare outcomes between different subgroups. In order to estimate the chance of survival for patients with ES, we developed a nomogram. Nomogram performance was evaluated by discrimination and calibration. Additionally, an analysis of decision curves was conducted to evaluate the clinical usefulness of this newly developed model.

RESULTS

In the primary cohort,320 met the inclusion criteria to be entered into this study. The median OS was 66.000 months (range 34.704 to 94.296 months), and the 1-, 3-, and 5-year OS rates were 70.7%, 56.1%, and 50.4%, respectively. For the validation cohort, we studied 136 consecutive patients. Age, primary site, grade, AJCC (American Joint Committee on Cancer) T, AJCC M, and surgery were included in the nomogram. The C-index values for the training set and validation set were 0.817 and 0.832, respectively. The calibration plots showed good agreement between the prediction and the observation. Based on the clinical decision curve, the model has a good clinical net benefit for ES patients.

CONCLUSIONS

It is the first study that developed an effective survival prediction model for patients with ES. Using this nomogram can assist in clinical decision-making as it has satisfactory accuracy. Even so, additional external validation is needed.

Proximal-type epithelioid sarcoma of vulva – Case series of a rare tumor

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Proximal-type Epithelioid sarcoma of the vulva is a rare, aggressive soft tissue neoplasm seen in young and middle-aged females.

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Biopsy of the lesion with immunohistochemistry aids in diagnosis and differentiating from benign mimics.

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Loss of INI1 is characteristic and seen in the majority.

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Surgery is the mainstay of management in localized disease.

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Recently, Tazemetostat has obtained accelerated FDA approval for use in locally advanced and metastatic settings.

Epithelioid sarcoma (ES) is rare and aggressive soft tissue neoplasm characterized by tumor cells showing epithelioid morphology and immunohistochemically, characteristic loss of INI1/ SMARCB1 in most cases. The proximal-type ES usually involves the deeper soft tissues of the vulva or perineum is an extremely rare entity with diagnostic challenges. Surgery is the mainstay of treatment in localized diseases. Radiation and chemotherapy are used in the advanced and metastatic setting, however, their role in the adjuvant setting is uncertain. Anthracycline and gemcitabine-based chemotherapy are given in metastatic and recurrent tumors. We report 4 cases of ES treated over a period of 6 years at our center. All the cases initially presented at a local hospital with vulvar swelling with a benign mimic (3/4) or squamous cell carcinoma (1/4). The median age of diagnosis was 34 years (range 17–80). The diagnosis was established with epithelioid morphology of tumor cells and immunohistochemically characteristic loss of INI1/SMARCB1 in all cases. 3 cases were treated with upfront surgery and two of them received adjuvant radiotherapy. One case received upfront palliative therapy due to lung metastasis at the time of presentation. On median follow-up of 24 months (2–63), 2 cases were disease-free. One case had a recurrence in the lungs and chest wall after a disease-free interval of 63 months. She underwent surgical excision of metastatic deposits, however developed second lung recurrence after 3 months and is being treated with Adriamycin-based chemotherapy. All patients are alive at the last follow-up.

A case of retroperitoneal tumor displaying epithelial differentiation, prominent myxoid stroma and loss of INI1/SMARCB1

The clinicopathological spectrum of INI1 deficient tumors is expanding. Epithelioid sarcoma (ES) is a rare sarcoma of uncertain differentiation, more often occurring in the extremities and uncommonly in the deep soft tissues. Histopathologically, it manifests in the form of classical, proximal, or hybrid types, the latter two characterized by rhabdoid cytomorphology. Immunohistochemically, ESs display loss of INI1/SMARCB1 and genetically associated with high percentage of SMARCB1 deletions

We report an extremely uncommon case of a retroperitoneal tumor in a 42-year-old male, who presented with abdominal discomfort. Radiologic imaging disclosed a 12 cm-sized retroperitoneal mass without involvement of any organ parenchyma. The patient underwent tumor excision with left-sided nephrectomy at another hospital. A review of the paraffin-embedded tissue sections revealed a multinodular tumor, composed of dyscohesive epithelioid tumor cells and focally arranged in cords, containing moderate to abundant, eosinophilic cytoplasm, vesicular nuclei, containing prominent nucleoli, including cells with rhabdoid cytomorphology, in a conspicuous myxoid stroma. A focal tumor area resembled proximal-type of ES. Immunohistochemically, tumor cells displayed positivity for pan cytokeratin (AE1/AE3), epithelial membrane antigen (EMA), vimentin and focally for CA125, while these were negative for CD34, S100 protein, CKIT, DOG1, and INI1/SMARCB1.

To the best of our knowledge, this constitutes the first case of a malignant tumor with epithelioid morphology, displaying myxoid matrix and loss of INI1/SMARCB1, resembling a myxoid variant of an epithelioid sarcoma and myoepithelioma-like tumor of the vulvar tumor, occurring in the retroperitoneum. A review of similar cases, differential diagnosis and treatment-associated implications are presented.

Epithelioid sarcoma of the parapharyngeal space: A case report

Epithelioid sarcoma (ES) was first described by Enzinger in 1970. It is a rare variant of soft tissue sarcoma with a 5-year overall survival (OS) rate of 50%. Here, we reported a case of epithelioid sarcoma in the parapharyngeal space of an adult, resulting in a favorable prognosis after chemotherapy and radiation therapy. A 34-year-old female who complained of pharynx pain and discomfort was suspected of having a tumor in the right parapharyngeal space by CT scan. Excision biopsy suggested epithelioid sarcoma. Clinical and radiological studies did not reveal tumor distant metastasis in the patient. After excisional biopsy, the patient underwent chemotherapy and external beam radiation treatment. She has remained alive for 2 years and 7 months without recurrence since her last treatment. In this paper, we also provide a detailed review of the role of radiotherapy in the treatment of epithelioid sarcoma in previously reported cases.

Myxoepithelioid tumour with chordoid features: a clinicopathological, immunohistochemical and genetic study of 14 cases of SMARCB1/INI1-deficient soft-tissue neoplasm

AIMS

Complete loss of SMARCB1/INI1 in soft-tissue tumours such as malignant rhabdoid tumour, epithelioid sarcoma, myoepithelial tumour of soft tissue and extraskeletal myxoid chondrosarcoma is often associated with high-grade malignancy and poor prognosis. The diagnosis is sometimes challenging, owing to histological similarities, so careful differential diagnosis is required. Therefore, soft-tissue tumours with complete SMARCB1/INI1 loss could potentially include an unknown entity.

METHODS AND RESULTS

We analysed 160 cases of SMARCB1/INI1-deficient soft-tissue tumour, and found 14 cases that were not classifiable into already existing categories and had common clinical and histological features. These involved two male and 12 female patients, ranging in age from 20 years to 61 years. The tumours were located in the the puboinguinal region (n = 13) and pelvic cavity (n = 1). Histologically, the tumours showed relatively uniform epithelioid to spindle-shaped cells with myxoid stroma. All tumours showed immunoreactivity for brachyury, epithelial membrane antigen, and progesterone receptor, and 12 of 14 cases did so for oestrogen receptor. Variable positive staining for α-smooth muscle actin, S100 and glial fibrillary acidic protein (GFAP) was seen. NR4A3 and EWSR1 gene rearrangements were not detected in 13 and 11 examined cases, respectively. Clinical follow-up data for the 14 patients showed that 13 were alive without disease and one had been lost to follow-up; four patients developed local recurrence and/or metastases.

CONCLUSION

The designation 'myxoepithelioid tumour with choroid features' (METC) was proposed as a tumour with intermediate malignancy controllable with appropriate treatment, including the entity of myoepithelioma-like tumour of the vulvar region. METC represents a novel and independent subset that is histologically, biologically and clinically distinct from already existing SMARCB1/INI1-deficient soft-tissue tumours.

SMARCB1/INI1-deficient tumors of adulthood

The SMARCB1/INI1 gene was first discovered in the mid-1990s, and since then it has been revealed that loss of function mutations in this gene result in aggressive rhabdoid tumors. Recently, the term "rhabdoid tumor" has become synonymous with decreased SMARCB1/INI1 expression. When genetic aberrations in the SMARCB1/INI1 gene occur, the result can cause complete loss of expression, decreased expression, and mosaic expression. Although SMARCB1/INI1-deficient tumors are predominantly sarcomas, this is a diverse group of tumors with mixed phenotypes, which can often make the diagnosis challenging. Prognosis for these aggressive tumors is often poor. Moreover, refractory and relapsing progressive disease is common. As a result, accurate and timely diagnosis is imperative. Despite the SMARCB1/INI1 gene itself and its implications in tumorigenesis being discovered over two decades ago, there is a paucity of rhabdoid tumor cases reported in the literature that detail SMARCB1/INI1 expression. Much work remains if we hope to provide additional therapeutic strategies for patients with aggressive SMARCB1/INI1-deficient tumors.

Early clinical and metabolic response to tazemetostat in advanced relapsed INI1 negative epithelioid sarcoma

Epithelioid sarcoma (ES) is a rare soft tissue sarcoma with an incidence of 0.05 per 100,000 population in the USA. It is characterized by multiple local recurrences and regional lymph nodes form the commonest site of metastases. The function of Integrase Inhibitor 1 (INI1) protein is lost in more than 90% of cases, which was the basis for the introduction of tazemetostat into the therapeutic armamentarium for management of advanced ES. The efficacy and manageable toxicity profile of tazemetostat have been demonstrated recently, leading to its accelerated approval for treatment of advanced ES. We report one of the first real-world cases of relapsed, metastatic ES treated with tazemetostat. The patient attained partial response with the therapy and is tolerating the drug well without serious toxicities.

Distal-type epitheloid sarcoma mimicking a wart in a child: A diagnosis not to be missed

Epithelioid sarcoma is a rare soft-tissue tumor that occurs mainly in children and young adults. It typically presents as a subcutaneous or deep dermal mass in distal extremities. Due to its benign-appearing clinical presentation, infrequent occurrence, and histologic similarities with other pathologies, the diagnosis of epithelioid sarcoma in its early stages can be extremely difficult and can be easily confused with benign lesions such as warts or foreign body granuloma. In this paper, we report the case of a 12-year-old boy with a distal-type epithelioid sarcoma of the hand and wish to emphasize the difficulties of diagnosing this potentially lethal tumor both clinically and histologically.

Role of immunohistochemistry in gynec oncopathology including specific diagnostic scenarios with associated treatment implications

Over the years, immunohistochemistry has emerged as a powerful tool for a more precise diagnosis of certain tumors in gynecologic oncopathology and resolving certain diagnostic dilemmas with significant treatment implications. Certain specific immunohistochemical (IHC) markers have been useful in the more correct identification of rare tumors, characterized by specific molecular signatures. Immunohistochemistry has also been useful in the identification of underlying genetic events, characterizing various tumors, as well as precancerous lesions. This review will focus upon the judicious application of various IHC antibody markers in gynec oncopathology, including authors' experience during "sign-outs" and especially during interaction with other oncology colleagues within the institutional disease management group. The updated references were retrieved from PubMed.

Epithelioid Sarcoma-From Genetics to Clinical Practice

Epithelioid sarcoma is a mesenchymal soft tissue sarcoma often arising in the extremities, usually in young adults with a pick of incidence at 35 years of age. Epithelioid sarcoma (ES) is characterized by the loss of SMARCB1/INI1 (integrase interactor 1) or other proteins of the SWI/SNF complex. Two distinct types, proximal and distal, with varying biology and treatment outcomes, are distinguished. ES is known for aggressive behavior, including a high recurrence rate and regional lymph node metastases. An optimal long-term management strategy is still to be defined. The best treatment of localized ES is wide surgical resection. Neo-adjuvant or adjuvant radiotherapy may be recommended, as it reduces the local recurrence rate. Sentinel lymph node biopsy should be considered in ES patients. Patients with metastatic ES have a poor prognosis with an expected median overall survival of about a year. Doxorubicin-based regimens are recommended for advanced ES. Tazemetostat, an EZH2 methyltransferase, has shown promising results in ES patients. Novel therapies, including immunotherapy, are still needed.

Proximal-type epithelioid sarcoma of the oral cavity: a case report and literature review

Proximal-type epithelioid sarcoma (PES) is an exceedingly rare malignant tumor of soft tissue; PES within the oral cavity is even rarer. Pathologic examination is the primary diagnostic modality, and surgical treatment is recommended as the preferred method for the treatment of PES. Currently, there is a paucity of literature that systematically reports on PES in the oral cavity. Here, we describe a 42-year-old man with PES in the oral cavity, which showed positivity for vimentin, cytokeratin, CD31, S-100 but did not express BCL-2, HMB-45, or desmin. We performed a wide excision and neck dissection, and then used the free anterolateral thigh flap to reconstruct the defect in the soft tissue. Furthermore, we review the current literature with regard to diagnosis and treatment of PES.

Epithelioid sarcoma in the chest wall: a case report and literature review

BACKGROUND

Epithelioid sarcoma (ES) is a rare variant of soft tissue sarcoma. The proximal type of ES occurs in various locations. We present a resected case with proximal-type ES that occurred in the chest wall and discuss the relevant literature.

CASE PRESENTATION

A 47-year-old woman was referred for a 6-month history of a right anterior chest mass with tenderness. Chest computed tomography showed an invasive chest wall mass with calcification surrounding the third rib. Aspiration biopsy cytology suggested malignancy. We performed wide resection, including the middle part of the pectoralis major muscle, the pectoralis minor muscle, the third and fourth ribs, and reconstruction of the chest wall, using a 2-mm polytetrafluoroethylene patch. Severe deformation of the chest wall was avoided. Postoperative physical therapy of the shoulder was effective for the continuous pain and weakness of the arm. She has remained alive for 1 year and 10 months without recurrence. Our literature review showed five previously reported cases of ES in the chest wall, and all of these were surgically resected. Two of these patients suffered from frequent local recurrence and died of disease.

CONCLUSIONS

ES in the chest wall is rare. Previous reports have indicated that surgical resection with tumor-free margins is essential for treatment. We performed complete resection of the tumor in our case, and a polytetrafluoroethylene patch was effective for reconstructing the deficit in the chest wall.

Can radical margins improve prognosis in primary and localized epithelioid sarcoma of the extremities?

INTRODUCTION

Epithelioid sarcoma (ES) has a tendency to locally recur, spread proximally, and metastasize, in particular to lymphnodes and lungs. The aim of this report is to study the role of surgery and the extent of margins required for optimal management of patients with localized epithelioid sarcoma of the extremities.

MATERIAL AND METHODS

We retrospectively evaluated 77 patients affected by ES of the extremities treated at two different Institutions.

RESULTS

Twenty-two patients had metastasis at diagnosis. Estimated survival was 65.5% at 5 years and 50.9% at 10 years, with a better prognosis in patients with localized disease at diagnosis (P < 0.001). Among patients with localized disease, a significantly better survival was found in patients with primary tumors in which radical surgical margins were achieved (P = 0.043). Among 47 patients presenting with primary tumors, local recurrence-free rate was 72.9% at 5 years, and 61.9% at 10 years, with a better local control achieved in patients with radical margins were achieved (P = 0.026).

DISCUSSION

We believe that the best approach to improve both local control and survival is to aim for radical margins in patients with primary tumors. Therefore, the best chance for cure is if the first treatment is the right treatment, which we believe to be radical margins.

Epithelioid sarcoma of the plantar fascia mimicking Morbus Ledderhose - A severe pitfall for clinical and histopathological misinterpretation

Plantar fibromatosis, also known as Morbus Ledderhose, is a well known and frequently encountered disorder of the planta pedis. When conservative treatment fails, surgical therapy with complete resection is the therapeutical procedure of choice. Soft tissue sarcoma is a heterogeneous and rare malignant disease of the musculoskeletal system with over 50 histopathological subtypes which can potentially arise in any localization but is most commonly found at the extremities. Here, we report the case of an epithelioid sarcoma of the sole of the foot which was initially and repeatedly clinically and histopathologically misinterpreted as plantar fibromatosis, receiving insufficient resection and subsequently ending in amputation of the lower leg.

INI Expressing Epithelioid Sarcoma with Osteoclastic Giant Cells in a Child: A Case Report with Summary of Prior Published Cases

BACKGROUND

Epithelioid sarcoma is a heterogeneous tumor with 2 subtypes, classic and proximal. The proximal variant is more aggressive and occurs in proximal location in young adults.

CASE REPORT

We present a proximal epithelioid sarcoma in the leg of an 8 year old girl with rhabdoid morphology and scattered osteoclastic giant cells. Nuclear INI-1 was retained. Despite wide local excision, local recurrence occurred at 8 months. Following re-excision, she developed a chest wall metastasis after 9 months.

CONCLUSION

Epithelioid sarcoma, proximal type with osteoclastic giant cells in the pediatric age group has not been reported previously and should be considered in the differential diagnoses of tumors with epithelioid cell morphology and scattered osteoclastic giant cells. Retained INI expression helped to differentiate this tumor from malignant rhabdoid tumor.

Points to notice during the diagnosis of soft tissue tumors according to the "Clinical Practice Guideline on the Diagnosis and Treatment of Soft Tissue Tumors"

To adequately treat soft tissue tumors, an accurate initial diagnosis is essential. In this article, we describe the notable points during initial diagnoses as outlined by the "Clinical Practice Guideline on the Diagnosis and Treatment of Soft Tissue Tumors". Clinical findings including pain and tumor size, growth speed, and depth, may be important in the diagnosis. In general, malignant soft tissue tumors tend to be larger than 5 cm in size, to occur in deep layers, and grow quickly. However, there are many exceptions. Magnetic resonance images can show characteristics of soft tissue tumors, but most of these are non-specific. The most reliable diagnostic procedure is histological examination. Therefore, a biopsy is mandatory. A core needle biopsy can be performed under local anesthesia at an outpatient clinic without the need for imaging guidance. In cases with deep-seated tumors, an image-guided biopsy is recommended. Incisional biopsies are also widely used procedures. In an incisional biopsy, the skin incision should be parallel to the long axis of the extremities. A meticulous hemostasis must be carried out to prevent post-biopsy hemorrhaging. If adequate hemostasis cannot be achieved, a drain is placed within the incision or at the closest possible site along the incision. Indications for an excisional biopsy are limited to superficial soft tissue tumors, less than 3 cm in size, located at a suitable distance from the nearest vital structure. Furthermore, an excisional biopsy should only be carried out after imaging studies are complete.

Indian data on bone and soft tissue sarcomas: A summary of published study results

Bone sarcomas are rare tumors, approximating 0.2% of all cancers, with osteosarcoma (OGS), chondrosarcoma, and Ewing sarcoma being the most common cancers in this subset. The formation of disease management groups/clinics focused on sarcomas has resulted in better understanding and management of these uncommon tumors. Multiple large-scale retrospective data from Tata Memorial Hospital (TMH) and All India Institute of Medical Sciences have reported outcomes comparable to Western data in the field of OGS and Ewing sarcoma, with interesting prognostic factors identified for further evaluation. Soft tissue sarcomas are a rare heterogeneous group of tumors, more than 50 different tumor entities. The common subtypes identified in India include Ewing sarcoma and synovial sarcoma. Valuable work regarding brachytherapy has been done by radiation oncologists from the TMH, especially in pediatric patients.

Management of Epithelioid Sarcoma of the Inguinal Region with Vascular Invasion

Epithelioid sarcoma (ES) is a rare clinically polymorphic tumor that mimics both benign and malignant conditions. It presents with dermal or subcutaneous nodules on the extremities in young adults. We present here a case of epithelioid sarcoma of the inguinal region infiltrating the femoral vessels. Biopsy is diagnostic and good histopathological evaluation is critical in management.

Successful Treatment with Pazopanib for Multiple Lung Metastases of Inguinal Epithelioid Sarcoma: A Case Report

Epithelioid sarcoma is a rare soft tissue sarcoma and usually resistant to chemotherapy. It has high rates of local recurrence and distant metastasis, and the prognosis after metastasis is poor. We report a case of multiple lung metastases of an epithelioid sarcoma originating in the inguinal area that we treated with the multikinase inhibitor pazopanib. The patient was a 38-year-old male who began to experience discomfort in his left inguinal area. Magnetic resonance imaging showed a tumor extended from the medial aspect of the wing of the left ilium along the iliopsoas muscle to its site of insertion on the femur. The histopathological diagnosis with a biopsy was proximal-type epithelioid sarcoma. Although a positron emission tomography examination showed fluorodeoxyglucose accumulation in the left inguinal tumor, there was no distant metastasis. Wide resection by a combined iliac resection procedure was performed. Twelve months after surgery, computed tomography revealed multiple nodules and a diagnosis of bilateral multiple lung metastases was made. Treatment with pazopanib 800 mg was started. After 2.5 months of treatment, a clear reduction in the size of the pulmonary metastases was shown. Thirty months after the start of pazopanib treatment, most of the metastases have disappeared, and no development of new lesions has been seen. Therefore, it appeared that pazopanib was capable of serving as one of the choices of therapeutic agents that should be taken into consideration for the treatment of advanced epithelioid sarcoma.

Prognostic Value of Relevant Clinicopathologic Variables in Epithelioid Sarcoma: A Multi-Institutional Retrospective Study of 44 Patients

Background

Epithelioid sarcoma (ES) is an extremely rare soft tissue sarcoma. Recently, the proximal variant has been reported to be a more aggressive subtype; however, as most reports of ES have involved small case series, the actual prognostic implications remain unclear. We investigated the clinicopathological features of patients with ES to identify the prognostic factors that influence survival.

Methods

We retrospectively analyzed the clinicopathological features of 44 patients with ES who had been treated at our institutions between 1991 and 2011. Among these patients, 26 were diagnosed histologically as having classic-type ES, whereas the remaining 18 had proximal-type ES. Thirty-three of the patients, all without distant metastases, underwent curative surgery, and the remaining 11 with distant metastases (M1) received palliative treatment.

Results

The proximal subtype was significantly correlated with a proximal tumor location, distant metastases at presentation, presence of rhabdoid cells, a higher tumor grade, and vascular invasion. The overall survival (OS) rate at 5 years for the 44 patients was 45 %. A superficial tumor location and lymph node metastases (N1) at presentation were independently predictive of local recurrence-free survival (LRFS), and N1 and M1 tumors were independently predictive of distant metastasis-free survival and OS, respectively. The proximal subtype was associated with unfavorable LRFS and OS, although not to a statistically significant degree.

Conclusions

Proximal-type ES has significantly more aggressive clinicopathological features than classic-type ES, and lymph node or distant metastasis has the most critical impact on prognosis.

Cutaneous malignant rhabdoid tumor in the palm of an adult

Malignant rhabdoid tumor is a rare tumor occurring mostly in the neonatal kidneys and central nervous system. Cutaneous malignant rhabdoid tumors are extremely rare in adults. The aim of the study was to report on the clinical, histologic, and immunophenotypic characteristics of this cutaneous malignant rhabdoid tumor which developed in an adult. A 27-year-old male complained of a right palm neoplasm that had been present for 6 months, which was initially diagnosed as an epithelioid sarcoma by biopsy. However, detailed investigation with immunohistochemistry enabled us to make a diagnosis of a rhabdoid tumor. The patient underwent radical abrasion, chemotherapy, and irradiation, and has survived for 1 year without relapse. Only 20 adult cases have been reported thus far in the English literature. We are reporting the 21^st case, who remains disease-free at 12 months. Complete resection and local irradiation may increase survival, because there is no standard and reliable curative chemotherapeutic regimen.

Proximal-type epithelioid sarcoma of the scrotum: 18F-FDG PET/CT imaging

Proximal-type epithelioid sarcoma is an uncommon but aggressive soft-tissue malignancy involving proximal body parts especially perineum and genitalia of adult patients. This entity is a variant form of the conventional epithelioid sarcoma, which is frequently encountered at extremities of adolescents or young adults. The authors present a case of proximal-type epithelioid sarcoma of the scrotum with comprehensive staging and monitoring with PET/CT.

Proximal-type epithelioid sarcoma: case report of an unusual presentation

Epithelioid sarcoma, first described by Enzinger in 1970, classically presents in young adults and usually arises in the distal extremities. The proximal-type variant, first described in 1997 as a rare aggressive form of sarcoma, usually arises more proximally. It carries a higher mortality rate than classical limb epithelioid sarcoma and is often resistant to multimodal treatment. We report the case of a 27-year old male who had a delayed diagnosis of proximal-type epithelioid sarcoma of the forearm. This was originally thought to be a necrotising soft tissue infection and was unfortunately metastatic at the time of eventual diagnosis. The clinical and histopathological features of this challenging tumour are discussed and the relevant literature is reviewed.

Revisiting chordoma with brachyury, a "new age" marker: analysis of a validation study on 51 cases

CONTEXT

Chordoma is a rare, notochordal tumor with a characteristic histomorphology and immunohistochemical profile. At times, it presents a diagnostic challenge, especially in small biopsies. Brachyury, a nuclear transcription factor, is a recently described immunohistochemical marker for diagnosing chordomas.

OBJECTIVE

To study the sensitivity and specificity of brachyury in diagnosing chordomas by comparing its expression in axial chordomas with nonchordomatous tumors.

DESIGN

Fifty-one axial chordomas, accessioned during a 10-year period, and 58 nonchordomatous tumors were subjected to brachyury staining by immunohistochemistry.

RESULTS

The 51 chordomas occurred in 36 men and 15 women. Sitewise, 34 cases (66.7%) occurred in the sacrococcyx, 9 (17.6%) in the spine, and 8 (15.7%) in the skull base. Histologically, 34 cases (66.7%) were classical chordomas, 13 cases (25.5%) had a dominant chondroid component, and 2 cases each (3.9%) were chondroid chordomas and dedifferentiated chordomas, respectively. Brachyury staining was positive in 46 of the 51 chordomas (90.2%) and negative in all 58 nonchordomatous tumors. The dedifferentiated area in 2 chordomas was negative for brachyury staining. Fourteen of 15 chordomas with chondroid component showed positive brachyury staining. Immunohistochemical expression of other markers, included cytokeratin (positive in 23 of 23 cases; 100%), epithelial membrane antigen (positive in 22 of 22 cases; 100%) and S100 protein (positive in 18 of 21 cases; 85.7%).

CONCLUSION

Exclusive brachyury expression in more than 90% of chordomas indicates its value as a unique, specific marker with other sensitive markers like cytokeratin, epithelial membrane antigen, and/or S100 protein in substantiating a diagnosis of chordoma, including on small biopsies.