Epithelioid sarcoma: clinical, MR imaging and pathologic findings

An infected chronic expanding haematoma treated with hip disarticulation

This is a report of an anticoagulated patient with septic shock caused by an infected chronic expanding haematoma (CEH) that required hip disarticulation as a means of definitive surgical source control. As far as we know, we did not find any report of an infected giant CEH in the lower extremity as large as in the present patient.

Delayed diagnosis of pediatric intra-articular epithelioid sarcoma: a case report and literature review

BACKGROUND

Epithelioid sarcoma (ES) is a rare form of mesenchymal malignancy that rarely occurs in children. Only seven cases of intra-articular epithelioid sarcoma have been reported in the medical literature.

CASE PRESENTATION

In this report, we presented the case of a 13-year-old girl with a delayed diagnosis of ES in the left knee. Her initial diagnosis was mistaken for Pigmented Villonodular Synovitis (PVNS) but ruled out later by the first biopsy. However, the lesion rapidly regrew again after arthroscopy, raising suspicions of malignancy. A comprehensive histochemistry examination was conducted again, leading to the diagnosis of INI-1 negative epithelioid sarcoma. Unfortunately, the girl passed away seven months later due to early metastasis of the tumor.

CONCLUSION

Careful consideration should be given to the differential diagnosis of pediatric patients presenting with monoarthritis. This report highlights the importance of early and accurate diagnosis and underscores the necessity for effective treatments for epithelioid sarcoma. Surgical resection or radical surgery is recommended, while novel treatment strategies targeting EZH2 show promise.

Epithelioid Sarcoma of the Spine: A Review of Literature and Case Report

Epithelioid sarcoma is a rare malignant mesenchymal tumor that represents less than 1% of soft-tissue sarcomas. Despite its slow growth, the overall prognosis is poor with a high rate of local recurrence, lymph-node spread, and hematogenous metastasis. Primary epithelioid sarcoma arising from the spine is extremely rare, with limited data in the literature. We review the existing literature regarding spinal epithelioid sarcoma and report a case of epithelioid sarcoma arising from the spinal cord. A 54 year old male presented with a 1-month history of progressive left upper-limb weakness and numbness. Magnetic resonance imaging (MRI) of the spine showed an enhancing intramedullary mass at the level of T1 also involving the left T1 nerve root. Systemic radiological examination revealed no other lesion at presentation. Surgical excision of the mass was performed, and histology was consistent with epithelioid sarcoma of the spine. Despite adjuvant radiotherapy, there was aggressive local recurrence and development of intracranial metastatic spread. The patient died of the disease within 5 months from presentation. To the best of our knowledge, spinal epithelioid sarcoma arising from the spinal cord has not yet been reported. We review the challenges in diagnosis, surgical treatment, and oncologic outcome of this case.

Imaging findings of primary epithelioid sarcoma of adrenal gland: a case report and literature review

Epithelioid sarcoma (ES) is a rare soft tissue malignant tumor with an uncertain histogenetic origin. It usually arises in soft tissues of the extremities, while ES in adrenal gland is extremely rare. There is no special clinical manifestation in the early stage, so it may be misdiagnosed and delay the treatment. We reported a 69-year-old male with an adrenal ES. The tumor was completely resected, and two months later, positron emission tomography-computed tomography(PET/CT) noted recurrence at the tumor bed and multiple metastases. The patient has been treated with chemotherapy with good effects. We summarize the radiological findings and immunohistochemical indexes of primary epithelioid sarcoma of adrenal gland, which may be useful to promote disease awareness and help to distinguish among other lesions.

Review of primary superficial soft tissue mesenchymal tumors of malignant or intermediate biological potential

The majority of the sarcomas are deep in location, larger than 5 cm in size, and heterogenous in imaging appearance. However, when sarcomas occur superficially, these typical features may be absent, failing to alert the radiologist to a malignancy and mimicking one of the more numerous benign superficial tumors that make up the bulk of soft tissue mass evaluations. This manuscript will discuss the current role of imaging in recognizing features concerning for superficial soft tissue sarcomas. Provided is an overview of the demographic, clinical, and imaging features of the most commonly encountered superficial soft tissue sarcomas, including undifferentiated pleomorphic, leiomyosarcoma, synovial sarcoma, liposarcoma, myxofibrosarcoma, dermatofibrosarcoma protuberans, epithelioid sarcoma, and angiosarcoma. A less common but primary superficial tumor, angiomatoid fibrous histiocytoma, is also reviewed as the diagnosis may be confounding both clinically and on imaging studies.

Neoplastic Elbow Diseases and Mimickers

Tumors around the elbow are infrequent, and delayed diagnosis is a common theme because of the low incidence and lack of familiarity. However, just like any other site, the radiologic work-up of musculoskeletal tumors around the elbow remains the same, with plain films the first investigation in a patient with a suspected bone tumor and ultrasound the first modality to evaluate a soft tissue lump. The management of both bone and soft tissue tumors around the elbow is unique because of a large number of important structures in an anatomically confined space and little normal tissue to spare without severely compromising the joint's function. Many benign nonneoplastic entities can mimic bone and soft tissue tumors on imaging. It is important to keep the characteristic imaging appearance in mind while formulating a differential diagnosis to avoid an unnecessary additional work-up. This article reviews the most common benign and malignant bone and soft tissue tumors around the elbow, mimickers, imaging features, and current therapeutic concepts.

Overview of malignant soft-tissue sarcomas of the limbs

Although soft-tissue masses are common, sarcomas are rare malignant neoplasms showing variable mesenchymal differentiation and can occur at any anatomical site. Limb soft-tissue sarcomas (STS) are rare, but often lethal tumours. Although there are scores of historical pathological subtypes, this article will deal with the commonest: liposarcoma, leiomyosarcoma (LMS), undifferentiated pleomorphic sarcoma (UPS), synovial sarcoma, myxofibrosarcoma, malignant peripheral nerve sheath tumour (MPNST), epithelioid sarcoma, alveolar rhabdosarcoma, angiosarcoma and radiation-induced sarcoma (RIS). Following a review of >4,000 adult patients with limb sarcoma from our specialist soft-tissue tumour database, we summarise the literature and their imaging findings, with emphasis on radiological hallmarks that can aide in diagnosis and management. Increased awareness of sarcoma when challenged with a new mass in the extremity can ensure timely and appropriate treatment.

Imaging of Pediatric Soft Tissue Tumors and Tumor-like Conditions

Lumps and bumps are frequently seen in children, and the vast majority are a result of trauma, infection, or inflammation. True soft tissue neoplastic lesions are rare; however, their wide and complex classifications make these lesions challenging to manage. Imaging features are usually nonspecific, and a reasonable list of differential diagnoses can be generated following consideration of the clinical presentation, age, and anatomical location of the lesion. In this article, we offer a practical approach to diagnosing such lesions by discussing the most common three benign and malignant lesions in different anatomical regions stratified by age with emphasis on certain features that might aid in the diagnosis such as depth, multiplicity, calcification, or other specific imaging feature.

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.

Diagnosis and management of primary malignant tumors in the upper extremity

Bone and soft tissue sarcomas of the upper extremity are relatively uncommon. In many cases, they are discovered incidentally during evaluation of traumatic injuries or common ailments such as rotator cuff tendonitis or tennis elbow. Thus, it is important for all orthopedic surgeons to understand the differential diagnosis, workup, and treatment for upper extremity lesions. An appreciation of the clinical and radiographic features of primary malignant lesions aids in identifying patients that need referral to an orthopedic oncologist and a multidisciplinary team.

Epithelioid Sarcoma of the External Auditory Canal: An Uncommon Tumor at an Unusual Site and a Brief Overview of the Literature

We present a case (41 years old pregnant female) with epithelioid sarcoma arising in the left external auditory canal. On immunohistochemistry, the tumor cell diffusely expressed cytokeratins and showed patchy expression of ERG and CD34. The neoplastic cells demonstrated uniform loss of INI1-expression. Epithelioid sarcoma arising in the external auditory canal is rare. Awareness that ES may rarely arise at unusual sites is of critical importance in order to apply a broad enough panel in the immunohistochemical study, so a misdiagnosis of carcinoma can be avoided.

An Extremely Rare Epithelioid Sarcoma Arising from the Infratemporal Fossa: A Case Report and Literature Review

INTRODUCTION

Epithelioid sarcoma (ES) is a rare histopathological type of soft tissue sarcoma. They are subcutaneous soft tissue masses that tend to arise in extremity sites (the classic type, formerly referred to as distal type) or proximal midline region of the body (the proximal type), such as the perineum, genital tract, and pelvis. The head and neck regions are rarely affected by ES, but the infratemporal fossa (ITF) is extremely rare. ES involving the ITF has not been reported before in literature. In this paper, the imaging features of ES were reviewed in detail, and the anatomical structure and epidemiology of ITF were briefly introduced.

SOURCES

We performed a systematic search from 3 databases, CNKI(China National Knowledge Internet), FMRS(Foreign Medical Literature Retrieval Service, Shenzhen METSTR Technology CO., Led. China), and PubMed, to obtain literature from January 1970 to July 2020. Epithelioid sarcoma, head and neck regions, infratemporal fossa, diagnostic imaging, anatomy, MRI, and CT were used as keywords for advanced retrieval. A study had to be found eligible for inclusion to be closely related to ES and/or ITF. A total of 129 related pieces of literature were retrieved successfully, of which 37 were closely related to this study. The case report in this article is from the Affiliated Hospital of North Sichuan Medical College. The present study was approved by the institutional review board of the Affiliated Hospital of North Sichuan Medical College and a written informed consent for the publication of the case was obtained from the patient.

CASE PRESENTATION

A 33-year-old man accidentally found a slowly growing, painless mass in the left cheek more than a month ago. On plain computed tomography (CT) scan of the outpatient department, an oval slightly low-density mass with well-defined and uniform boundary in the infratemporal fossa was revealed, and on the contrast-enhanced scan, it was homogeneous and moderately enhanced. Initially, the CT appearance favored benign lesions. However, the possibility of a malignant tumor can not be excluded completely. Finally, the patient was referred to the inpatient department a tumor arose from IF and underwent a selective operation. The tumor was completely removed. Histologic findings were compatible with epithelioid sarcoma. Post-operatively, the patient received 2 cycles of radiotherapy, and there was no evidence of recurrence after 6 months follow- up.

CONCLUSION

The imaging manifestations of ES are various. The anatomic structure of ITF is complex and the pathological types are various. It should be very careful in the qualitative diagnosis of tumors from the ITF, and advanced imaging techniques will be useful in imaging diagnosis.

Ultrasonography of Pediatric Superficial Soft Tissue Tumors and Tumor-Like Lesions

Ultrasonography (US) is usually the first imaging examination performed to evaluate palpable or visible superficial soft tissue lesions that are common in children. Although clinical assessments, such as age at presentation, clinical course, and overlying skin discoloration, are important for the differentiation of pediatric soft tissue lesions, US allows a specific diagnosis of some typical benign lesions and helps in guiding further investigation since it provides detailed information about the lesion location, characterization including solid versus cystic, vascularity, and compressibility. Therefore, sufficient knowledge of the normal anatomy, proper ultrasonographic techniques, and the imaging findings of common and uncommon soft tissue lesions in children are crucial for accurate assessment and management of patients. In this article, we review the techniques and imaging findings focusing on the ultrasonographic features of a variety of superficial soft tissue lesions detected in children.

Ultrasound and Magnetic Resonance Imaging Features of Calcifying Aponeurotic Fibromas

OBJECTIVES

To report characteristic imaging findings of calcifying aponeurotic fibromas (CAFs) on ultrasound (US) and magnetic resonance imaging (MRI).

METHODS

Eight patients with CAF based on our institutional pathology database from 2000 to 2019 were consecutively included. Images were assessed as follows: with plain radiographs for the presence of soft tissue calcifications; with US for the presence of microlithiasis (a nonshadowing hyperechoic focus <3 mm) and discrete calcifications, size, location, margin, echogenicity, and relationship with surrounding structures; and with MRI for the presence of MRI microlithiasis (scattered tiny signal-void dots), margin, signal intensity, contrast enhancement pattern, and relationship with surrounding structures.

RESULTS

Calcifying aponeurotic fibromas occurred most commonly in the foot (n = 5), followed by the hand, ankle, and knee, respectively. Half of the lesions (n = 4) showed intralesional calcifications on plain radiographs. On US, all lesions showed microlithiasis. They involved the subcutaneous (n = 5), perifascial (n = 2), and intermuscular (n = 1) layers. Margins were circumscribed (n = 3) or irregular (n = 5), whereas the echogenicity of the underlying tumor matrix was hyperechoic (n = 4), isoechoic (n = 2), or hypoechoic (n = 2). All lesions were abutting (n = 7) or encasing (n = 1) an adjacent tendon. On MRI, all CAFs showed tiny signal-void dots and irregular margins. Signal intensity was mostly hyperintense (n = 5) on T2-weighted images and all hypointense on T1-weighted images. Three lesions showed heterogeneous contrast enhancement, and 3 showed uneven marginal enhancement.

CONCLUSIONS

A CAF should be considered a differential diagnosis if a soft tissue mass abutting or encasing the tendon or fascia shows US or MRI microlithiasis.

MRI of Rhabdomyosarcoma and Other Soft-Tissue Sarcomas in Children

Soft-tissue sarcomas in children comprise a heterogeneous group of entities with variable manifestation depending on the age of the patient and the location of the tumor. MRI is the modality of choice for evaluating musculoskeletal soft-tissue tumors and plays a paramount role in both initial diagnosis and assessment of tumor response during and after treatment. Conventional MRI sequences, such as T1- and T2-weighted imaging, offer morphologic information, which is important for localizing the lesion and describing anatomic relationships but not accurate for determining its malignant or benign nature and may be limited in differentiating tumor response from therapy-related changes. Advanced multiparametric MRI offers further functional information that can help with these tasks by using different imaging sequences and biomarkers. The authors present the role of MRI in rhabdomyosarcoma and other soft-tissue sarcomas in children, emphasizing a multiparametric approach with focus on the utility and potential added value of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI in characterization and staging, determination of pretreatment extent, and evaluation of tumor response and recurrence after treatment. ^©RSNA, 2020.

Achilles tendon reconstruction with peroneus tendon transfer following epithelioid sarcoma resection: a rare case report at 5 years follow-up

BACKGROUND

Soft-tissue sarcomas (STS) are rare in hand and foot. In this paper we present a case of reconstruction of Achilles tendon defect with peroneus brevis transfer reinforced with medial gastrocnemius fascia and plantaris tendon after excision of a local recurrence of epithelioid sarcoma.

CASE PRESENTATION

Fifty-five years-old female. MRI showed a lump of 5 × 2,5 × 2 cm into Achille's tendon with invasion of the anterior fat tissue but no invasion of the surrounding bones. The patient underwent excision of the tumour and reconstruction of the tendinous defect with peroneus brevis transfer. Surgical technique has been widely described.

DISCUSSION AND CONCLUSIONS

Epithelioid sarcoma arising from the Achilles tendon is an extremely rare malignant tumour in an atypical site and may easily be confused with other soft tissue masses. It presents a technical challenge because of the large tendon defect remaining following wide resection. Reconstruction with peroneus brevis transfer, reinforced with medial gastrocnemius fascia and plantaris tendon, restore appropriate structural continuity and resistance. Functional results are satisfactory.

Post-amputation neuroma of radial nerve in a patient with ephitelioid sarcoma: case report and literature review

Neuroma, also known as traumatic neuroma or amputation neuroma or stump neuroma, is a focal non neoplastic area of proliferative hyperplastic reaction secondary to peripheral nerve damage that commonly occurs after a focal trauma (acute or chronic) or surgery, such as amputation or partial transection. Neuromas are more commonly located in the lower limbs, followed by head and neck; other extremely rare sites include the ulnar nerve followed by the radial nerve and the brachial plexus. A radiologic plan is necessary to recognize soft tissue lesions with a neural origin and whether they are a true tumor or a pseudotumor such as a neuroma, fibrolipoma, or peripheral nerve sheath ganglion. In oncologic patients the appearance of post-surgical neuromas can produce problems in differential diagnosis with local recurrences. Therefore, with a combination of different imaging techniques, mainly ultrasound (US) and magnetic resonance imaging (MRI), it is possible to characterize neurogenic tumours safely, with a great impact on patient management and to plan an appropriate treatment. Here, we report the first case of post-amputation neuroma of radial nerve in a patient with clinical history of ephitelioid sarcoma with a short literature review. (www.actabiomedica.it)

Soft-Tissue Tumors of the Hand-Imaging Features

Imaging studies of the hands and fingers are common, and radiologists are generally comfortable with traumatic and degenerative conditions which arise frequently in daily practice. However, a variety of common and uncommon soft-tissue tumors also occur in the hand, the appropriate diagnosis of which can be a source of confusion for both clinicians and radiologists. These lesions often have overlapping imaging characteristics; however, a structured approach can help provide a focused differential diagnosis and impact further workup and management. We discuss several such tumors, categorizing them as cystic-appearing, noncystic masses along tendons and aponeuroses, adipocytic tumors, vascular lesions, and miscellaneous lesions with imaging features that can aid diagnosis.

Magnetic resonance and computed tomography imaging features of epithelioid sarcoma in children and young adults with pathological and clinical correlation: a report from Children's Oncology Group study ARST0332

OBJECTIVE

To correlate imaging features of epithelioid sarcoma in children and young adults enrolled in Children's Oncology Group study ARST0332 with clinical and pathological findings.

MATERIALS AND METHODS

Fifteen patients (6 males; median age 16.1 years, range 6.5-24.8 years) with epithelioid sarcoma enrolled in ARST0332 had preoperative imaging (MRI, n=10; CT, n=5) that was reviewed by two radiologists who recorded numerous features including presence and percentage of tumor necrosis, presence of surrounding edema, and lymph node involvement. Discrepancies between reviewers were adjudicated by concurrent re-review. We correlated imaging findings with histological assessment of percentage tumor necrosis, proximal- vs. classic-type histology, lymph node involvement and recurrence.

RESULTS

Eleven patients (11/15, 73%) had proximal-type histology tumors. Ten of 14 tumors (71%) had imaging evidence of necrosis. Among the nine tumors with imaging and histological estimates of percentage necrosis, agreement was within 30% (in six tumors there was ≤10% difference between pathology and imaging). All 10 tumors imaged with MRI had surrounding edema. Four patients had biopsy-proven nodal involvement; all had necrotic nodes on imaging. There were four false-positives for nodal involvment by imaging. Twelve patients (12/15, 80%) had recurrences (local only, n=1; local and distant, n=1; distant only, n=10).

CONCLUSION

Proximal-type histology was prevalent in this young cohort with preoperative imaging. Necrosis is common in primary tumors and involved nodes. There is good agreement between histological and imaging estimates of primary tumor necrosis. Surrounding tumor edema is common in this tumor, which is known to spread along fascial planes.

Epithelioid sarcoma arising from the temporal space: A case report

INTRODUCTION

Epithelioid sarcoma is a malignant soft tissue tumor arising from mesenchymal tissue and usually occurs in the extremities. The tumor involving the head and neck region is extremely rare. We present radiologically well-documented case of an epithelioid sarcoma arising from the temporal space.

CASE PRESENTATION

A 35-year-old woman presented with a slowly growing, painless palpable mass in the left temporal area. Ultrasound (US) revealed a lobulated hypoechoic mass with internal vascularity. On magnetic resonance (MR) imaging, the mass showed heterogeneous signal intensity with a central necrotic area and peritumoral infiltration. On the basis of the clinical and radiological characteristics, the lesion was considered to be a malignant tumor originating from soft tissue. An incisional biopsy was performed. The diagnosis of epithelioid sarcoma was based on microscopic examination and immunohistochemical analysis. F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) was used to stage the tumor and demonstrated intense FDG uptake in the mass without regional lymph node or distant metastasis. After the pathologic diagnosis of epithelioid sarcoma, the patient underwent total surgical resection of the tumor followed by postoperative irradiation. There was no evidence of recurrent disease during the follow-up period of 18 months.

CONCLUSION

An epithelioid sarcoma should be considered in the differential diagnosis of a locally aggressive lesion occurring in the temporal space of head and exhibiting a heterogeneous appearance on imaging studies, including a central necrotic area and signal intensity suggestive of infiltration of soft tissue adjacent to the tumor. It is, however, true that head-and-neck involvement is very rare, and the radiological findings are not pathognomonic.

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.

MR Imaging of Soft-Tissue Tumors of the Upper Extremity

Certain soft-tissue tumors seem to be specific to the upper extremity; most are benign. Knowledge of key magnetic resonance features, with clinical history and epidemiologic knowledge, can assist the radiologist in establishing optimal diagnosis. Indeterminate lesions require biopsy to exclude malignancy.

Soft tissue angiofibroma: a case report

Soft tissue angiofibroma is a recently described neoplasm that typically presents as a slowly growing, painless mass in the soft tissues of the lower extremities. Cytogenetic and molecular studies have identified a recurrent t(5;8) translocation. Treatment is simple excision. Existing data suggest that this tumor is benign and has a low rate of local recurrence. The radiologic and pathologic differential diagnoses for this lesion include both benign and malignant lesions, including plantar fibromatosis, tenosynovial giant cell tumor, fibroma of tendon sheath, epithelioid sarcoma, and low-grade myxofibrosarcoma. Proper identification of this benign lesion through radiologic and pathologic correlation is important to prevent misdiagnosis of a low-grade sarcoma.

Epithelioid sarcoma presenting as radial mononeuropathy: anatomical, magnetic resonance neurography and diffusion tensor imaging appearances

The authors report an unusual case of radial mononeuropathy caused by epithelioid sarcoma and describe the anatomical 3-Tesla MR neurography and the functional diffusion tensor imaging findings of the case, which were subsequently confirmed on surgical excision and histopathology.

Imaging of the most frequent superficial soft-tissue sarcomas

Superficial soft-tissue sarcomas are malignant mesenchymal tumors located within the cutaneous and/or subcutaneous layers. Most superficial soft-tissue sarcomas are low-grade tumors; yet, the risk of local recurrence is high, and initial wide surgery is the main prognostic factor. Some of these superficial sarcomas may grow, following an infiltrative pattern, and their real extent may be underestimated clinically. Imaging techniques are useful to determine precisely the real margins of the tumor, especially in cases of clinically doubtful or recurrent or large superficial lesions. Imaging tools enable one to determine the relationship with the superficial fascia separating the subcutaneous layer from the underlying muscle. In our institution ultrasonographic examination is followed by magnetic resonance (MR) imaging when the size of the lesion exceeds 3-5 cm. Imaging assessment is performed prior to biopsy, enabling optimal surgical management. Imaging features of the main superficial sarcomas are detailed in the following article, according to their major locations: those arising in the epidermis and/or dermis, which are most often diagnosed by dermatologists, and the subcutaneous sarcomas.

Epithelioid sarcoma of the neck: case report

Epithelioid sarcoma is an aggressive, malignant tumour of the soft tissue which tends to arise in proximity to large tendons and aponeuroses. We report the case of a patient presenting with an epithelioid sarcoma arising in the neck. A 56-year-old man was referred with a three-year history of a sensory disorder as well as a slowly growing mass in his right neck. The patient underwent resection of the tumour by means of a conservative neck dissection. The final diagnosis, based on the histological and immunohistochemical findings, was epithelioid sarcoma. Radiotherapy was performed after the operation. The post-operative course was uneventful, and there was no local recurrence or distant metastasis.

Pediatric soft-tissue tumors and pseudotumors: MR imaging features with pathologic correlation: part 2. Tumors of fibroblastic/myofibroblastic, so-called fibrohistiocytic, muscular, lymphomatous, neurogenic, hair matrix, and uncertain origin

In the final part of this two-part review article on soft-tissue masses in children, the magnetic resonance (MR) imaging features, clinical findings, and pathologic findings in a wide variety of tumors, including those of fibroblastic/myofibroblastic origin, so-called fibrohistiocytic tumors, smooth-muscle tumors, skeletal-muscle tumors, tumors of uncertain differentiation, and lymphoma, are described. Other neoplasms that are not included in the World Health Organization classification of soft-tissue tumors but may be seen clinically as soft-tissue masses, specifically dermatofibrosarcoma protuberans, neurogenic tumors and pilomatricoma, are also included. In contrast to the tumors reviewed in Part 1 of this review, the MR imaging features and clinical findings of the tumors included here are largely nonspecific. However, MR imaging is useful in determining site of tumor origin, extent of disease, and relation of tumor to adjacent anatomic structures, and for follow-up after therapy. In some of these entities, the combination of findings may aid in narrowing the differential diagnosis, such as persistent low signal intensity on T1- and T2-weighted images in some fibroblastic lesions, identification of hemosiderin and a synovial origin in pigmented villonodular synovitis, or the presence of multiple target signs on T2-weighted images in deep plexiform neurofibroma. In a large number of cases, however, tissue biopsy is required for final diagnosis.

Epithelioid sarcoma of the forearm arising from perineural sheath of median nerve mimicking carpal tunnel syndrome

We report here a case of epithelioid sarcoma in the forearm of a 33-year-old male presenting with symptoms and signs of carpal tunnel syndrome originating from the direct involvement of the median nerve. Due to the slow growing of the tumor, the patient noticed the presence of tumor mass in his forearm after several months from the initial onset of the symptoms. Magnetic resonance imaging showed an 8 × 4 cm mass involving the median nerve in the middle part of the forearm, and histological analysis of the biopsy specimen revealed the diagnosis of epithelioid sarcoma. Radical surgical resection was performed in conjunction with adjuvant chemotherapy. The function of the flexors were restored by the multiple tendon transfers (EIP → FDS; ECRL → FDP; BrR → FPL; EDM → opponens) with superficial cutaneous branch of radial nerve transfer to the resected median nerve. The function of the affected hand showed excellent with the DASH disability/symptom score of 22.5, and both the grasp power and sensory of the median nerve area has recovered up to 50% of the normal side. The patient returned to his original vocation and alive with continuous disease free at 3.5-year follow-up since initial treatment.

Lymphoma presenting as a musculoskeletal soft tissue mass: MRI findings in 24 cases

The purpose was to describe the MRI morphological features and signal intensity (SI) characteristics of 24 histologically proven cases of musculoskeletal soft tissue lymphoma presenting clinically as a suspected primary soft tissue sarcoma. This was a retrospective review of clinical notes and MRI studies of 24 patients with a histologically confirmed diagnosis of lymphoma. All patients presented to a specialist orthopaedic oncology unit with a suspected primary soft tissue sarcoma. Features assessed included lesion size and morphology, location, extension across anatomical compartments and signal intensity characteristics. The lesions were predominantly poorly defined with peritumoral oedema in ten cases. All tumours were of intermediate T1W SI, while 85% of lesions also showed intermediate T2W SI. Almost all cases that were located just deep to the fascia showed subcutaneous extension, while 50% had involvement of more than one muscle compartment. In 29% of cases, there was extension of tumour along the neurovascular bundle. Histo-pathologically, 23 lesions were non-Hodgkin's B-cell lymphoma. The MRI features of primary musculoskeletal soft tissue lymphoma include a mass with intermediate SI on T1W and T2W images, involvement of more than one anatomical compartment, subcutaneous extension and extension along the neurovascular bundle.

Clinical significance of magnetic resonance imaging in the preoperative differential diagnosis of calcifying aponeurotic fibroma

BACKGROUND

Although the clinical and histological features of calcifying aponeurotic fibroma are well described, the magnetic resonance imaging (MRI) findings have been reported for only five cases. The purpose of this study was to describe a series of MRI findings in this rare entity to assess its utility in preoperative and differential diagnosis.

METHODS

MRI findings together with the clinical signs and radiographs of six patients with pathologically proven calcifying aponeurotic fibroma were retrospectively reviewed. Distribution, morphology, margins, edematous changes, and relation to the surrounding structures together with signal intensity of each sequence of MRI were evaluated.

RESULTS

MRI demonstrated subcutaneous distribution, ill-defined appearance, and a tendency to infiltrate into or adhere to the surrounding tissues. The masses were of isointensity to low intensity on T1-weighted images. T2-weighted images showed heterogeneous high signal intensity with minor areas of isointensity to low signal intensity. Postcontrast T1-weighted images demonstrated heterogeneous intense enhancement.

CONCLUSIONS

MRI revealed several features that can contribute to the preoperative differential diagnosis of calcifying aponeurotic fibroma from other fibrous tumors, giant cell tumor of the tendon sheath, or soft tissue sarcoma. As a result, MRI would help orthopedic oncologists plan the surgery for this rare entity.

Magnetic resonance imaging features of extremity sarcomas of uncertain differentiation

The purpose of this review is to illustrate the pertinent clinical and imaging features of extremity sarcomas of uncertain differentiation, including synovial sarcoma, epithelioid sarcoma, clear-cell sarcoma, and alveolar soft part sarcoma. These tumours should be considered in the differential diagnosis when a soft-tissue mass is encountered in the extremity of an adolescent or young adult.

Epithelioid sarcoma of the median nerve mimicking a peripheral nerve sheath tumour

We describe a case of epithelioid sarcoma of the median nerve in a 57-year-old woman presenting with symptoms and signs of carpal tunnel syndrome for 2 years. The clinical examination was suggestive of a wrist ganglion compressing the median nerve. Magnetic resonance imaging (MRI) showed a 5 cm x 3 cm mass involving the median nerve in the carpal tunnel and appearances mimicked a benign peripheral nerve sheath tumour. This report illustrates a rare tumour presenting in a rare location and emphasizes the atypical clinical and MRI features that should alert the radiologist to the possibility of a rare sarcoma mimicking a benign peripheral nerve sheath tumour.

Superficial soft-tissue masses of the extremities

Superficial soft-tissue masses are among the most common indications for imaging of the extremities. A broad array of benign and malignant processes may be manifested in palpable cutaneous or subcutaneous masses or nodules. Most such lesions are treated with surgical excision, but some may be conservatively managed. The lesions can be differentiated according to their location in one or more skin layers (epidermis, dermis, and subcutis), their histologic composition, and the associated anatomic abnormality or disease process. Because the imaging characteristics of many benign soft-tissue lesions overlap with those of malignant ones, knowledge of the patient's clinical history (including any laboratory test results) and direct visual examination of the lesion often are important for differentiation. Histologic analysis may be necessary to achieve a definitive diagnosis.

Soft-tissue sarcoma mimicking large haematoma: a report of two cases and review of the literature

We report on 2 patients with soft-tissue sarcomas mimicking large haematomas. Neither patient had a medical history of trauma or bleeding tendency. In a patient with a large leiomyosarcoma in the buttock, insufficient biopsy material from initial surgeries precluded a correct diagnosis. In the second patient with epithelioid sarcoma of the forearm, fasciotomy was repeatedly performed for compartment syndrome arising from the tumour. It is important to reconfirm prior trauma and investigate the clinical course and images of patients with an unusual history of haematoma in the extremities. The possibility of a malignant tumour should be suspected, and repeated biopsies should be performed if necessary.

MRI of merkel cell carcinoma: histologic correlation and review of the literature

OBJECTIVE

The objective of this study was to determine the MRI characteristics of Merkel cell carcinoma, with an emphasis on histologic correlation.

MATERIALS AND METHODS

The demographic information about 15 patients from our institution and their MRI examinations were retrospectively reviewed by three musculoskeletal radiologists by consensus for lesion location and intrinsic characteristics. The study group was composed of three women and 12 men who ranged in age from 48 to 87 years, with a mean age of 75 years. Histology results of resected specimens were reviewed in all cases and were correlated with imaging.

RESULTS

MRI showed skin thickening, subcutaneous reticular stranding (n = 9, 60%); multiple anatomically aligned subcutaneous soft-tissue masses, representing lymphatic tumor nodules (n = 5, 33%); lymph node enlargement with fine, compressed, retained fatty tissue (n = 5, 33%); nodal necrosis (n = 1); and perifascial and intramuscular metastases (n = 2). Histology confirmed the lymphatic nature of the soft-tissue Merkel cell tumors.

CONCLUSION

Patients with Merkel cell tumors may present at imaging with subcutaneous lymphatic reticular stranding, multiple subcutaneous masses, and lymph node metastases. Often there is massive lymph node enlargement with fine, compressed, retained fatty tissue.

Epithelioid sarcoma of the hand

Twenty-eight patients were treated for a primary epithelioid sarcoma of the hand. Twenty-seven patients (96%) had excisions before evaluation, including 11 (39%) with multiple prior excisions with varying diagnoses before epithelioid sarcoma, and all had surgical treatment after referral. The patients' surgical management included three patients with amputation at the forearm, three patients with wide excision, and 21 patients with a partial amputation of the hand. The followup period averaged 120 months (range, 24-276 months). Eighteen patients have no evidence of disease at last followup. Treatment failures included one local recurrence, four regional metastases, and five distant metastases. Five patients died secondary to disease. Two patients are alive with disease, and three are alive with no evidence of disease after additional treatment. After aggressive surgical management with negative margins, 71% of the patients were alive without evidence of disease at the last followup, with a 5- and 10-year survivorship of 85%. Our goal is to review: (1) the effectiveness of preoperative imaging, (2) the role of adjuvant therapy, (3) survival after alternative resections, and (4) function after resection.

MRI of epithelioid sarcoma of the thigh

A 31-year-old woman with epithelioid sarcoma of the thigh is presented. The patient had had a progressively growing mass in her left thigh for 4 months. Magnetic resonance imaging (MRI) showed a subcutaneous mass with a central area of hypointensity and serpiginous hyperintensity in the peripheral portion. Such findings have not been reported before. Histologic findings were compatible with epithelioid sarcoma.

MR imaging of tumors and tumor-like lesions of the upper extremity

Many tumor and tumor-like lesions of the bone and soft tissues may involve the upper extremity. Certain lesions, however, are unique to this location. As is usually the case, MR is most sensitive to detection and most accurate in depicting the extent of involvement of these lesions. MR signal characteristics may aid in differential diagnosis. Conventional radiographs are often more specific in regard to the underlying histopathology.

Epithelioid sarcoma metastatic to the tongue: a rare entity

Epithelioid sarcoma (ES) typically arises as a firm nodule on the extremities of young men. The tumor is remarkable for diagnostic difficulties both clinically and histopathologically resulting in a high frequency of initial misdiagnosis. ES is also known to have a high rate of recurrence and high rate of metastasis predominantly to the lymph nodes, lungs, and scalp. Herein, the second case of ES with metastasis to the tongue is reported.