Alveolar soft part sarcoma: MR and angiographic findings

Complete Response to Pembrolizumab in Stage IV Alveolar Soft Part Sarcoma After Failure of Four Lines of Treatment: A Case Report and Literature Review

Alveolar soft part sarcoma (ASPS) is a rare malignant tumor that manifests as a slow-growing soft tissue mass and frequently presents with distant metastasis. The prognosis is variable, and complete remission of metastatic disease has rarely been reported. Our patient was diagnosed with metastatic ASPS at the age of 17, with a primary forearm lesion and metastasis to the lungs. She underwent surgical resection of her forearm mass, followed by adjuvant chemotherapy and radiation to target the lung metastasis. Over the next decade, she had a complicated course of treatment. Her disease continued to slowly progress despite treatment with sunitinib, pazopanib, and a combination of docetaxel and gemcitabine. We eventually treated her with immune checkpoint inhibitors (ICIs). Pembrolizumab, initially in combination with bevacizumab and later as monotherapy, resulted in significant tumor shrinkage, especially in the pulmonary lesions, within the first three months. Subsequent imaging reported complete remission within 15 months and no disease recurrence at her three-year follow-up. Our case highlights one of the very few reported cases of complete remission achieved in metastatic ASPS after treatment with ICIs. ICIs could offer hope for disease remission in advanced ASPS, a rare malignancy that has proven difficult to treat successfully in the past. More studies need to be conducted to further evaluate the efficacy and any associated predictors of successful treatment.

The use of the flow-void sign on MRI: highly sensitive sign in detecting bone metastases from renal cell carcinoma

OBJECTIVE

To evaluate a range of pathologically proven malignant bone tumours, including primary bone sarcoma and metastatic bone lesions, referred to a tertiary referral centre for the presence of the flow-void sign on MR imaging.

MATERIALS AND METHODS

A retrospective search was performed using the radiology information system and oncology database in our institution to identify patients over the age of 40 years referred with a solitary bone lesion. Patients with a range of pathologically proven malignant bone tumours, including primary bone tumours and metastatic bone lesions, were included in the study. MRI images were reviewed for the presence of the flow-void sign. The presence and type of the flow-void sign were correlated with lesion size.

RESULTS

Two hundred and sixty-six cases were included in the study. Overall, the flow-void sign was identified in 40.9% of cases. The flow-void sign was most frequently seen in renal cell carcinoma metastasis (90.0%). The sign is highly sensitive (90%) for renal cell carcinoma metastases with a high negative predictive value (98.09%). When the flow-void sign is identified, the lesion is almost three times more likely to represent a renal cell carcinoma metastasis than any other malignant tumour in patients over the age of 40 years with a solitary bone lesion.

CONCLUSION

The flow-void sign is highly sensitive for renal cell carcinoma bone metastases and could negate the need for biopsy in patients with a known history of renal cell carcinoma or in whom an occult renal cell carcinoma is subsequently identified.

Imaging Features of Alveolar Soft Part Sarcoma: Single Institution Experience and Literature Review

Alveolar soft part sarcoma (ASPS) is an extremely rare and aggressive soft-tissue sarcoma (STS) subtype with poor prognosis and limited response to radiation therapy and chemotherapy. Prompt recognition and referral to sarcoma centers for appropriate management are crucial for patients' survival. The purpose of this study was to report ASPS pre-treatment imaging features and to examine the existing literature on this topic. Twelve patients (7 women, 5 men-mean age 27.1 ± 10.7 years) were included from our single-center experience. Ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) available were reviewed according to an analysis grid incorporating features from the latest research on STS. Clinical, histological, and outcome data were collected. MRI was available in 10 patients (83.3%), US in 7 patients (58.3%), and CT in 3 patients (25%). Mean longest tumor diameter was 7.6 ± 2.9 cm, and all tumors were deeply seated. Large peritumoral feeding vessels were systematically found and identified on ultrasonography (7/7), MRI (10/10), and CT (3/3). US revealed a well-defined heterogeneous hypoechoic pattern, with abundant flow signals in all patients (7/7). In all patients, MRI showed mildly high signal intensity (SI) on T1-WI and high SI on T2-WI and peritumoral edema. Moreover, flow-voids (due to arteriosus high-flow) into the peritumoral/intratumoral feeding vessels were detected in the MRI fluid-sensitive sequences of all patients. At baseline, whole-body contrast-enhanced CT revealed metastases in 8/12 (66.7%) patients. A pre-treatment longest diameter > 5 cm was significantly associated with distant metastases at diagnosis (p = 0.01). A maximum diameter > 5 cm represents a risk of metastatic disease at diagnosis (odds ratio = 45.0000 (95% CI: 1.4908-1358.3585), p = 0.0285). In the comprehensive literature review, we found 14 articles (case series or original research) focusing on ASPS imaging, with a total of 151 patients included. Merging our experience with the data from the existing literature, we conclude that the hallmark of ASPS imaging at presentation are the following characteristics: deep location, a slight hyperintense MRI SI on T1-WI and a hyperintense SI on T2-WI, numerous MRI flow voids, high internal vascularization, and large peritumoral feeding vessels.

Sonographic imaging features of alveolar soft part sarcoma: Case series and literature review

BACKGROUND

Alveolar soft part sarcoma (ASPS) is a rare tumor but potentially fatal condition. Understanding the imaging and clinical features of ASPS is of certain value for preoperative qualitative diagnosis and clinical treatment of tumors. Nevertheless, there have been only 11 documented case reports describing the sonographic features in the English literature.

METHODS

Three patients with confirmed ASPS occurring primarily in the limbs were enrolled in this study. Complete surgical excision was performed with conservative limb function. We pay particular attention to the ultrasonographic features and performed a literature review of ASPS cases.

RESULTS

With regular surveillance, one patient had no symptom recurrence and two developed lung and/or breast metastasis later. The specific sonographic findings were heterogeneous hypoechoic, well-circumscribed, and lobulated or round contours on grayscale images, abundant flow signals of intratumoral and extratumoral tubular structures on color Doppler images.

CONCLUSION SUBSECTIONS

Its low incidence rate and lack of characteristic clinical manifestations often result in misdiagnosis of ASPS. The specific sonographic findings may add useful diagnostic information.

Alveolar soft part sarcoma of the orbit: A case report

Alveolar soft part sarcoma is a rare soft tissue neoplasm that accounts for approximately 1% of all sarcomas and is usually identified in the extremities in adults. The occurrence of alveolar soft part sarcoma in the orbit is extremely rare, estimated at approximately 5% – 15% among all cases of alveolar soft part sarcoma . Here, we present a case of 29-year-old woman with orbital alveolar soft part sarcoma. We describe the magnetic resonance and F-18 2-fluoro-2-deoxy-D-glucose-position emission tomography/computed tomography findings of this case. This young woman had a spindle-shaped mass. A higher signal compared to the extraocular muscle on T1-weighted images, numerous flow voids on T2-weighted images, and intense enhancement could be key findings of this disease.

Imaging of Soft Tissue Tumors

Differentiation of malignant from benign soft tissue tumors is challenging with imaging alone, including that by magnetic resonance imaging and computed tomography. However, the accuracy of this differentiation has increased owing to the development of novel imaging technology. Detailed patient history and physical examination remain essential for differentiation between benign and malignant soft tissue tumors. Moreover, measurement only of tumor size based on Response Evaluation Criteria In Solid Tumors criteria is insufficient for the evaluation of response to chemotherapy or radiotherapy. Change in metabolic activity measured by ¹⁸F-fluorodeoxyglucose positron emission tomography or dynamic contrast enhanced-derived quantitative endpoints can more accurately evaluate treatment response compared to change in tumor size. Magnetic resonance imaging can accurately evaluate essential factors in surgical planning such as vascular or bone invasion and "tail sign". Thus, imaging plays a critical role in the diagnosis and treatment of soft tissue tumors.

Cutaneous leiomyosarcoma mimicking arteriovenous malformation

There is a clinical overlap between hypervascularized sarcomas and arteriovenous malformations (AVM). MRI imaging should be interpreted with caution keeping in mind that some cancers could mimic AVM. A biopsy is mandatory in doubtful cases.

iCREATE: imaging features of primary and metastatic alveolar soft part sarcoma from the EORTC CREATE study

Background

Alveolar Soft Part Sarcoma (ASPS) is a rare, slow-growing, but highly vascular soft tissue sarcoma, characterised by a high rate of metastases at presentation. Although imaging features of the primary are well described, less detail is available on the imaging pattern of metastatic ASPS. The EORTC 90101 (CREATE) study assessed the efficacy of Crizotinib in patients with metastatic ASPS and presents a unique opportunity to describe the imaging phenotype of primary and metastatic ASPS, based on prospectively collected imaging.

Methods

A retrospective review of the staging CT scans of 32 patients with ASPS from the CREATE study was undertaken and the imaging features of primary and metastatic disease were assessed.

Results

Imaging of the primary tumour was available in 7/32 cases (28%). All primary tumours demonstrated marked vascularity with prominent feeding vessels (7/7, 100%). The most frequent sites of metastases included lung (30/32, 94%), nodal (7/32, 22%), bone (5/32, 16%) and muscle/subcutaneous (5/32, 16%). Features of hypervascularity were identified at all sites, more appreciable in the lungs, with feeding vessels frequently demonstrated in pulmonary metastases (21/32, 66%).

Conclusion

Analysis of imaging from the CREATE cohort of patients with metastatic ASPS demonstrates that metastases from ASPS are predominantly hypervascular and demonstrate feeding vessels comparable to primary ASPS, suggesting potential sensitivity of this rare sarcoma for antivascular/antiangiogenic treatment approaches.

Computed tomography, magnetic resonance imaging, and F-deoxyglucose positron emission computed tomography/computed tomography findings of alveolar soft part sarcoma with calcification in the thigh: A case report

BACKGROUND

Alveolar soft part sarcoma (ASPS) is an extremely rare malignant sarcoma, accounting for less than 1% of all soft-tissue sarcomas. However, limited information is available on multimodal imaging [computed tomography (CT), magnetic resonance imaging (MRI), and positron emission computed tomography/computed tomography (PET/CT)] of ASPS.

CASE SUMMARY

This study reports a case of a 35-year-old female patient with ASPS of the left thigh with lung metastasis. The patient presented with a 1-year history of a palpable mass in the lower extremity, which exhibited rapid growth for 3 wk. CT, MRI, and F-deoxyglucose PET/CT examinations were performed. CT showed a slightly hypodense or isodense mass with patchy calcifications. On MRI examination, the mass manifested hyperintensity on T1-weighted, T2-weighted, and diffusion-weighted images with some signal voids. PET/CT images demonstrated an intensely hypermetabolic mass in the left thigh and hypermetabolic nodules in lungs.

CONCLUSION

ASPS should be considered as a possible diagnosis when a slow-growing mass is detected in the soft tissue of the extremities, with hyperintensity and numerous signal voids on T1-weighted, T2-weighted, and diffusion-weighted images and intense F-deoxyglucose uptake on PET/CT. ASPS can have calcifications on CT.

Soft Tissue Special Issue: Imaging of Bone and Soft Tissue Sarcomas in the Head and Neck

Bone and soft tissue sarcomas of the head and neck are a heterogenous group of tumors with overlapping features. Distinguishing between the various subtypes is challenging but necessary for appropriate diagnosis and management. The purpose of this article is to discuss the role of imaging in evaluating head and neck tumors, provide a general radiographic approach in differentiating between benign versus malignant lesions and give examples of selected subtypes of bone and soft tissue sarcomas in the head and neck with classic or pathognomonic imaging findings.

Alveolar Soft Part Sarcoma Metastasizing to the Brain: A Rare Entity Revisited with Review of Recent Literature

A 20-year-old male patient presented with a recent history of two episodes of seizures and Glasgow Coma Scale of E3V3M6. He was drowsy at presentation with bradycardia. On further examination, he was found to be having a 10 × 6cm well-circumscribed mass in the right medial thigh whose fine needle aspiration cytology was suggestive of soft tissue sarcoma. Contrast-enhanced magnetic resonance imaging brain showed enhancing lobulated lesions in bilateral hemispheres with significant edema. A decision to decompress the intracranial space occupying lesion was taken. Left-sided larger brain lesions underwent total gross excision followed by excision of the thigh mass. Histopathology of brain lesion was suggestive of metastatic deposits of alveolar soft part sarcoma, whereas the thigh mass was suggestive of alveolar soft part sarcoma grade 2 according to Fédération Nationale des Centres de Lutte Contre Le Cancer grading system. Postoperative course of the patient was unremarkable and his general condition improved remarkably (Functional Assessment of Cancer Therapy–Brain version 4 score improvement >50% at 1 month). He is in follow-up for the last 12 months and currently has completed chemoradiotherapy and is living a self-sufficient life. Though patients with aforementioned rare diagnosis have overall poor prognosis, decompressive craniotomy with metastasectomy may improve the overall quality of life of such young patients, and further chemoradiotherapy may help in prolonging life with acceptable level of comorbidity. This case is being discussed here in terms of the rarity of the final diagnosis, the management strategy used, and the quality of life improvement.

Alveolar soft part sarcoma of the forearm

Alveolar soft part sarcoma (ASPS) is a rare form of soft-tissue sarcoma arising from connective tissue. It is most often seen in adolescents and young adults and has high propensity for recurrence and metastasis. Clinically, it mimics haemangioma or arteriovenous malformations. In our case report, an 18-year-old female presented with markedly vascular tumour in the left forearm, for which excision biopsy was done. Histopathological report revealed ASPS. The patient was screened for metastasis. Ultrasound abdomen, computed tomography (CT) chest, CT brain and whole-body skeletal survey was done. The patient was found to have bilateral pulmonary metastasis. The patient was given 6 cycles of chemotherapy with adriamycin, cyclophosphamide and vincristine. There was no locoregional and pulmonary recurrence for 11 months after being treated by excision of the tumour followed by chemotherapy.

Imaging in Soft Tissue Sarcomas: Current Updates

Soft tissue sarcomas (STS) are heterogeneous malignant tumors that have nonspecific imaging features. A combination of clinical, demographic, and imaging characteristics can aid in the diagnosis. Imaging provides important information regarding the tumor extent, pretreatment planning, and surveillance of patients with STS. In this article, we illustrate the pertinent imaging characteristics of the commonly occurring STS and some uncommon sarcomas with unique imaging characteristics.

Brain metastatic alveolar soft-part sarcoma: Clinicopathological profiles, management and outcomes

Alveolar soft-part sarcoma (ASPS) is a rare sarcoma that presents in the buttocks or thigh of young adults and often metastasizes to the brain. The present study examined the clinical features and morphology of brain metastatic ASPS. The case records of eight patients with brain metastatic ASPS admitted between November 2008 and March 2015 were reviewed. The relevant clinical data (including patient age and sex, neuroimaging studies, histopathological and immunohistochemical features, surgical records and follow-up reports) were collected through a review of patient records. The sex distribution was 3:1 male to female and the age ranged between 15 and 33 years at the time of surgery. In total, five patients with brain metastases had concurrent pulmonary metastases. The lesions were hypointense on T1-weighted images in every patient, hyperintense on T2-weighted images in six patients and contrast enhancement was present in all patients. The most notable immunohistochemical feature was strong immunohistochemical staining for TFE3 in each patient. Gross total resection was performed in all eight patients, with two patients undergoing adjuvant radiotherapy and one undergoing adjuvant chemotherapy. Four recurrent cases were observed during the follow-up. TFE3 staining and knowledge of its microscopic characteristics would facilitate earlier diagnosis: Early diagnosis with a multidisciplinary, multimodal approach to treatment is required to achieve extended disease-free survival in patients with brain metastatic ASPS.

Laryngeal alveolar soft part sarcoma: A case report of a rare malignancy in an atypical location

Laryngeal sarcoma is a rare and potentially aggressive malignancy. In this case report, we present a 23year-old-male with four-years of progressive hoarseness who was found to have a large left paraglottic mass. A partial laryngectomy was successful at completely excising the lesion. Final pathology returned as alveolar soft part sarcoma. Alveolar soft part sarcomas of the larynx are extremely rare with only five cases published in the current literature. This article provides a case presentation with literature review of alveolar soft part sarcoma of the head and neck.

Surgical management and outcome of spinal alveolar soft part sarcoma (ASPA): a case series of five patients and literature review

Background

Alveolar soft part sarcoma (ASPS) is a rare entity of soft tissue malignancies with uncommon spinal involvements. Surgical management should be the best choice of cure.

Methods

Five patients with spinal ASPS were interviewed retrospectively, where data was collected. The relevant literatures were also systematically examined. Thereafter, patient and surgical data were obtained and pooled for prognostic analysis.

Results

A total of five patients with eight surgeries were reviewed retrospectively, and three patients previously reported were also included. All patients were surgically treated, where five of them underwent additional adjuvant therapies such as chemotherapy, radiotherapy, and targeted therapy in order to manage their local and/or systematic diseases. One patient was lost in follow-up. For the remaining seven patients, the mean follow-up period was 19.7 ± 8.8 months, two succumbed to disease while five were alive at the time of the study.

Conclusions

Surgical management is shown to be the most important and the most effective treatment strategy for spinal ASPS, whereas adjuvant therapies made little impact. The prognostic factors for spinal ASPS are primary or metastatic lesions, neurological status, disease progression, systematic conditions, and resection approaches.

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.

Pelvic retroperitoneal pleomorphic hyalinizing angiectatic tumor (PHAT) of soft tissue: a case report

Background

Pleomorphic hyalinizing angiectatic tumor (PHAT) is a rare soft tissue tumor of low malignant potential, which most often arises in the lower extremities. Lesions occurred in other anatomic locations have been rarely reported. Moreover, their imaging features have not been well discussed. Here we report a case of PHAT arising primarily in the pelvic retroperitoneum. To our knowledge, this is the first radiological description for retroperitoneum PHAT.

Case presentation

A 26-year-old female was referred to our hospital for evaluation of a pelvic mass incidentally noted in routine pre-pregnancy ultrasonography examination. Magnetic resonance imaging (MRI) and computed tomography (CT) scan revealed an irregular mass with clear boundary in the pelvic retroperitoneum. Its signal intensity or density was inhomogeneous. On MRI images, it mainly showed isointense and slight hypointense on T1 weighted image and isointense and hyperintense on T2 weighted image. On contrast-enhanced images, it showed marked but heterogenous enhancement. With the delay time increasing, the enhanced area in the lesion increased but the CT value decreased. Dilated vessels and hemorrhage were detected in the tumor. With patience and careful separation, it was completely excised with great amount of bleeding during operation. Pathological and immunohistochemistry analysis confirmed the diagnosis of PHAT of the soft parts. We found no evidence of recurrence 18 months after operation.

Conclusion

We present an extremely rare case of PHAT arising primarily in the pelvic retroperitoneum. To our knowledge, this is the first radiological description for retroperitoneum PHAT. The provided information is useful for summarizing the characteristics of this kind of tumor. It should be included in the differential diagnosis of a well-defined, inhomogenously enhanced hypervascular soft-tissue mass in pelvic cavity.

Clinical presentation and CT/MRI findings of alveolar soft part sarcoma: a retrospective single-center analysis of 14 cases

BACKGROUND

Alveolar soft part sarcoma (ASPS) is a relatively rare malignant tumor and early diagnosis and appropriate treatment for ASPS are essential for a good prognosis.

PURPOSE

To retrospectively review the clinical presentation and computed tomography (CT) and magnetic resonance imaging (MRI) findings of ASPS so as to improve the accuracy of imaging diagnosis.

MATERIAL AND METHODS

Fourteen patients with pathologically proven ASPS were enrolled. Their clinical and imaging findings were retrospectively reviewed.

RESULTS

The median age of the patients was 29 years (range, 13-37 years). Most tumors were located in the soft tissues of the trunk and lower limbs. The median maximal diameter of the masses was 91 mm. Thirteen masses presented with ovoid or irregular shapes. Eleven masses had less clear boundaries. Compared with the adjacent muscles, the masses were isodense or hypodense on CT, hypo-, iso-, or hyperintense on T1-weighted images, and heterogeneous hyperintense on T2-weighted images. Intense enhancement was seen after contrast agent administration, with prominent intra- or peri-tumoral feeders on CT or flow voids on MRI. By the end of the last follow-up, 13 patients had distant metastasis and three patients had local recurrence.

CONCLUSION

ASPS should be included in the differential diagnosis when a bulky, heterogeneous soft tissue mass in the trunk and the lower limbs with intense enhancement after contrast administration and prominent intra- or peri-tumoral feeders on CT or flow voids on MRI is seen, particularly in young patients.

Alveolar Soft Part Sarcoma

Alveolar soft part sarcoma is a rare neoplasm usually arising in the soft tissues of the lower limbs in adults and in the head and neck region in children. It presents primarily as a slowly growing mass or as metastatic disease. It is characterized by a specific chromosomal alteration, der(17)t(X:17)(p11:q25), resulting in fusion of the transcription factor E3 (TFE3) with alveolar soft part sarcoma critical region 1 (ASPSCR1) at 17q25. This translocation is diagnostically useful because the tumor nuclei are positive for TFE3 by immunohistochemistry. Real-time polymerase chain reaction to detect the ASPSCR1-TFE3 fusion transcript on paraffin-embedded tissue blocks has been shown to be more sensitive and specific than detection of TFE3 by immunohistochemical stain. Cathepsin K is a relatively recent immunohistochemical stain that can aid in the diagnosis. The recent discovery of the role of the ASPSCR1-TFE3 fusion protein in the MET proto-oncogene signaling pathway promoting angiogenesis and cell proliferation offers a promising targeted molecular therapy.

Magnetic resonance imaging and computed tomography features of alveolar soft-part sarcoma in the right deltoid muscle: A case report

Alveolar soft-part sarcoma (ASPS) is a rare, highly vascular malignant soft-tissue tumor that predominantly affects young adults. The tumor can occur in any bodily region, but is most frequently observed in the lower deep soft tissues of the extremities, and is rarely observed in the upper extremities. The present study reported a case of ASPS of the right deltoid muscle. The patient presented with a 3-year history of a mass on the right shoulder that exhibited rapid growth in the month prior to diagnosis. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed. The lesion mainly demonstrated isointense or mildly hyperintense signals compared with the muscle on the T1-weighted images of the MRI, and heterogeneous high signal intensity on the T2-weighted images. CT enhancement showed a homogeneous enhanced mass. The tumor was resected and submitted for histopathological examination. The diagnosis was verified as ASPS by microscopic examination and immunohistochemical analysis. No distant metastases were noted. No evidence of local tumor recurrence was seen at 6 weeks following the wide surgical excision. The CT scan revealed no metastatic nodules in either lung during the follow-up. ASPS should be considered as a possible diagnosis when a slow-growing, large mass is detected in young adults in the soft tissue of the extremities, with high signal intensity and numerous signal voids on T1-weighted images (T1WI) and T2WI, and strong contrast-enhancement.

Alveolar soft-part sarcoma in the left forearm with cardiac metastasis: A case report and literature review

Alveolar soft-part sarcoma (ASPS) is an uncommon soft-tissue neoplasm, which is commonly found in the deep soft tissues of the extremities, with a propensity for recurrence and metastasis. However, the metastasis of ASPS to the heart is exceedingly rare. The present study reports such a rare case with cardiac metastasis. Using computed tomography, a 37-year-old man was diagnosed with brain, lung and spleen metastases from a previously treated ASPS in the left forearm. Cardiac metastasis was then diagnosed 1 month later. Despite chemotherapy and palliative whole-brain radiotherapy, the patient succumbed to the disease shortly after. This case suggests that the widespread metastases and cardiac involvement of ASPS may result in a poor outcome.

Imaging features of alveolar soft-part sarcoma: a report from Children's Oncology Group Study ARST0332

OBJECTIVE

There are few studies in the literature regarding the imaging features of alveolar soft-part sarcoma (ASPS). We performed a comprehensive assessment of the imaging characteristics of this rare tumor to determine whether there are features that suggest the diagnosis.

MATERIALS AND METHODS

Twenty-two subjects with ASPS underwent pretherapy imaging as part of enrollment in Children's Oncology Group protocol ARST0332 for the treatment of nonrhabdomyosarcoma soft-tissue sarcomas: 16 patients underwent MRI; three, CT; and three, both MRI and CT. Two radiologists retrospectively reviewed the imaging studies by consensus and recorded tumor location, size, contour, internal architecture, signal characteristics, presence of flow voids, and enhancement patterns.

RESULTS

The 12 females and 10 males in the study group ranged in age from 8 to 23 years 7 months (mean, 15 years 8 months). The most common anatomic site was the lower extremity (12/22, 55%) followed by the upper extremity (4/22, 18%). The maximal tumor diameter ranged from 2.3 to 20.0 cm (median, 5.9 cm). All tumors imaged with MRI had flow voids (19/19, 100%), and 19 (19/22, 86%) had large peripheral vessels, lobulated margins, and nodular internal architecture. Unenhanced T1-weighted MRI was available for 18 tumors: 14 (14/18, 78%) appeared slightly hyperintense to muscle. Of the 16 tumors imaged with contrast material, 11 (11/16, 69%) showed intense enhancement and five (5/16, 31%), moderate enhancement. Six tumors (6/16, 38%) had a thick enhancing peripheral rim with a nonenhancing center consistent with necrosis.

CONCLUSION

The imaging features of ASPS include flow voids, large peripheral vessels, internal nodularity, and lobulated margins. Contrast administration produces intense to moderate enhancement, sometimes with a thick enhancing peripheral rim around central necrosis. Extremity tumors with these imaging features in a child or young adult should suggest the diagnosis of ASPS.

Primary Intracerebral Alveolar Soft Part Sarcoma in an 11-Year-Old Girl: Case Report and Review of the Literature

Alveolar soft part sarcoma (ASPS), a rarely observed tumor, is a soft tissue sarcoma with an unidentified cell origin. It constitutes 0.5–1.0% of all soft tissue sarcomas. It may appear in various parts of the body, but mostly observed in the trunk and the extremities. It has a high metastasis potential. To the best of our knowledge, only three cases of primary intracranial ASPS without a demonstrable lesion elsewhere is encountered. An 11-year-old girl was operated because of fronto-parietal mass lesion by craniotomy. Pathological examination revealed ASPS and no primary focus was detected. In spite of radiotherapy and chemotherapy as an adjuvant therapy, after 45 months she had a second operation for recurrence of the tumor. Since it is possible to observe metastases in late phases, up to 30 years, the patients must be followed up for a long period. Although radiotherapy and chemotherapy followed by surgery is the most accepted treatment strategy, the prognosis is still poor.

Imaging features of primary and metastatic alveolar soft part sarcoma: single institute experience in 25 patients

OBJECTIVE

To describe imaging features of primary and metastatic alveolar soft part sarcoma (ASPS).

METHODS

In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant retrospective study, 25 patients (14 males; mean age, 25 years; range, 18-40 years) with pathologically proven ASPS seen at our institute between 1995 and 2013 were included. Imaging of primary tumours in 5 patients and follow-up imaging in 25 patients were reviewed by 2 radiologists in consensus. Clinical information was obtained from electronic medical records.

RESULTS

The most common sites for the primary tumour were extremities (17/25, 68%) and torso (6/25, 24%). Primary tumours (n = 5) were well circumscribed, compared with skeletal muscle, were isodense on CT, hyperintense on T1 and T2 weighted images with intense post-contrast enhancement, prominent feeders on CT and flow voids on MRI. Metastases developed in 23/25 (92%) patients, 18 at presentation. The most common sites of metastases were the lungs (100%), lymph nodes (74%), bones (57%) and brain (43%). Visceral and nodal metastases were hypervascular. At the time of reporting the results, 15 patients have died, 6 are alive and 4 were lost to follow-up. Median survival was 74 months for those without brain metastases (n = 8) and 60 months for those with brain metastases (n = 7). Median survival was shorter for patients with metastases at presentation.

CONCLUSION

ASPS most commonly involves the lower extremities of young adults, is hypervascular on imaging, often metastasizes at presentation, frequently to lung, nodes, bones and brain, and has an indolent course despite metastases. Brain metastases and high tumour burden (number of metastatic sites) at presentation decreased survival in our study.

ADVANCES IN KNOWLEDGE

ASPS has an unusual pattern of metastases to the brain and nodes in addition to lung and bones. It has an indolent course despite metastases.

Alveolar soft part sarcoma: clinical presentation, treatment and outcome in a series of 19 patients

Background

Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor that usually affects young patients. Because of the rarity of the disease, most reports relating to ASPS are in the form of case reports or small series.

Methods

We performed a retrospective study to evaluate the clinicopathologic features, treatment, outcome and pattern of treatment failure in a consecutive series of patients with localized or metastatic ASPS between 1996 and 2011. Demographics, tumor sizes, sites and extent of disease, treatments provided, progression-free survival, and overall survival were evaluated.

Results

A total of 19 patients were identified. The clinical assumptive diagnosis of the first medical examination doctor was benign soft tissue tumor in 5 cases (26%) and benign hemangioma in 4 cases (21%), delaying treatment. The most common location of primary tumor was the thigh. The median diameter of the mass was 55 mm (range, 10 to 130 mm). An R0 resection was obtained in 11 cases. Adjuvant radiotherapy was delivered in 8 cases; postoperative systemic chemotherapy was delivered in 10 cases. Eight out of 15 patients (53%) exhibited metastases either at presentation or later. Median overall follow-up was 54 months.

Conclusions

The treatment principle for alveolar soft tissue sarcoma is massive resection, and when the surgical margin is questionable, radiation treatment can be added for prevention of local recurrence. Also, due to discovery of metastases and local recurrence, even after 5 years of general treatment, outpatient department follow-up is needed, and we need to keep in mind that lung, intracranial, and bone metastases are common.

Magnetic resonance imaging features of alveolar soft part sarcoma: report of 14 cases

Background

The purpose of this study was to assess the magnetic resonance imaging findings of alveolar soft part sarcoma.

Methods

Magnetic resonance images of pathologically proven alveolar soft part sarcoma in 14 patients were retrospectively reviewed, including lesion location, size and shape, border definition, signals on T1-weighted and T2-weighted images, presence or absence of peritumoral and intratumoral flow voids, and enhancement pattern.

Results

Patients included five women and nine men, ranging in age from 27 to 54 years, with a mean age of 36 years. A slow-growing mass without pain was the chief complaint. Eight patients had pulmonary metastases at presentation. Ten lesions arose from the extremities, two were located in the gluteal regions, one affected the presacral space and one occurred in the back. The mean maximal size of the lesions was 9.8 cm, ranging from 6.2 to 16 cm. All lesions appeared as a round (n = 2), ovoid (n = 8) or irregular (n = 4) shape with ill-defined margins. The lesions mainly demonstrated isointense or mildly hyperintense compared to muscle on T1-weighted images, and heterogeneous high signal intensity on T2-weighted images. Peritumoral edemas were observed in six patients. Ten lesions showed intense inhomogeneous enhancement after contrast. Intra- and peritumoral tubular flow voids representing tortuous dilated vessels with rapid blood flow were present in all cases.

Conclusions

Alveolar soft part sarcoma has some distinctive magnetic resonance imaging features including a slow-growing, large mass in the soft tissue of the extremities in young adults, with numerous signal voids on T1-weighted and T2-weighted images, and strong enhancement after contrast.

Alveolar soft part sarcoma: unusual etiology of mediastinal mass in an adolescent

Alveolar soft part sarcoma (ASPS) is a rare malignancy that usually arises in an extremity. Mediastinal involvement is uncommon, with only two reports of primary mediastinal disease and two reports of metastatic mediastinal disease in the literature, all referencing adult patients. To our knowledge, ours is the first report of ASPS presenting with a mediastinal mass in adolescence. Although ASPS is not generally included in the differential for adolescent mediastinal masses, it should be considered when clinical presentation and imaging appearance are characteristic.

Alveolar soft part sarcoma-radiologic patterns in children and adolescents

BACKGROUND

Alveolar soft part sarcoma is a rare but highly malignant tumour and little is known about its radiologic pattern in children.

OBJECTIVE

To describe the radiologic features of alveolar soft part sarcoma in children and adolescents.

MATERIALS AND METHODS

We retrospectively analysed the clinical and imaging data of six children age 7-17 years at diagnosis, with histologically or genetically proven alveolar soft part sarcoma.

RESULTS

The tumours were located deep within muscles of the limbs (n = 4), in chest wall muscle (n = 1) and in the orbit (n = 1). High-flow feeding arteries, large drainage veins and intense enhancement were consistent findings by all imaging modalities. At MRI, all tumours demonstrated high signal intensity on T2-weighted images and high or iso-intense signal on T1-W imaging compared to muscle. In tumours larger than 70 mm in one dimension (n = 3/6), large vessels converging toward the tumour centre led to a highly vascularised central stellar area pattern. Five children demonstrated synchronous (n = 4/5) and metachronous (n = 1/5) lung metastases.

CONCLUSION

Alveolar soft part sarcoma should be suggested when a highly vascularised, intramuscular mass demonstrating large feeding and drainage vessels converging toward a central stellar area is seen in children, especially if synchronous lung metastases are present.

Highly malignant soft tissue sarcoma of the extremity with a delayed diagnosis

Purpose

To evaluate the characteristics of highly malignant soft tissue sarcoma of the extremity with a delayed diagnosis.

Materials and methods

The clinical and radiological characteristics of 18 cases of highly malignant soft tissue sarcomas of the extremity with a delayed diagnosis were determined.

Results

Ten men and eight women of mean age 44.8 years (range, 15-79 years) were included in this study. Seven cases of synovial sarcoma, three cases each of alveolar soft part sarcoma and malignant fibrous histiocytoma, two cases each of highly malignant leiomyosarcoma and myxofibrosarcoma, and one case of clear cell sarcoma were enrolled. Times from tumor detection to diagnosis ranged from 1 to 3 years in most cases; three of the seven synovial sarcoma cases took more than 10 years to diagnose. Of the seven cases of synovial sarcoma, five cases of small, superficial located masses were simply excised without a pre-surgical biopsy. Three cases of alveolar soft part sarcoma showed characteristic T1- and T2-weighted high signal intensities with signal voids in MR images. In addition, one synovial sarcoma patient and one alveolar soft part sarcoma patient showed evidence of calcification on plain radiographs. However, no general characteristic clinical findings were found to be common to the 18 cases.

Conclusions

Contrary to general expectations, some soft tissue tumors that grow slowly are painless, and those that occur in superficial limbs may be highly malignant. Thus, even when a slow growing, painless superficial mass is encountered in a limb, physicians should keep the possibility of highly malignant soft tissue sarcoma in mind.

Alveolar soft part sarcoma: clinical presentation, treatment, and outcome in a series of 33 patients at a single institution

BACKGROUND

Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor that usually affects young patients. A comprehensive retrospective review was performed of clinical presentation, treatment, outcome, and patterns of failure in a consecutive series of patients with localized or metastatic ASPS between 1975 and 2008.

METHODS

Demographics, tumor sizes, sites and extent of disease, treatments provided, progression-free survival, and overall survival were evaluated.

RESULTS

A total of 33 patients were identified. Preoperative imaging misdiagnosed a vascular malformation in three cases (9%), delaying treatment. The most common location of primary tumor was the thigh. The median diameter of the mass was 9 cm (range, 2-15 cm). The tumor was deeply located in most cases (78.7%). A R0 resection was obtained in 27 cases. Adjuvant radiotherapy was delivered in 12 cases, in 6 cases in association with chemotherapy; preoperative systemic chemotherapy was delivered in 4 cases, in the adjuvant setting in another 3 cases. Twenty-one (63.6%) of 33 patients exhibited metastases either at presentation (10 patients, 30.3%) or later. Metastatic sites included lymph nodes, lung, bone, and liver. Median overall follow-up was 72 months. Overall survival was 68.7% at 5 years and 53.4% at 10 years. Metastectomies were performed in 33% of metastatic cases (7 of 21 patients).

CONCLUSIONS

Prognosis of ASPS is basically related to the characteristics of the disease and the quality of surgery. Overall, the occurrence of distant metastases is quite common, with a typical indolent course. New agents are eagerly needed to complement surgery to eradicate this disease.

Primary alveolar soft part sarcoma of vertebra: a case report and literature review

Alveolar soft part sarcoma (ASPS) is a rare malignant soft tissue tumor, which rarely occurs in bone. We present a case of ASPS in a 23-year-old man with a 2-month history of back pain. Computed tomography scanning and magnetic resonance images demonstrated a destructive process in the 12th thoracic vertebra associated with a unilateral soft tissue mass. The tumor showed evidence of hypervascularity on MRI; it obviously was enhanced on T1-weighted images after injection of Gd-GDPA, and signal voids were shown on all pulse sequences which may help to differentiate ASPS from other tumors of the vertebra. We believe that this is the first case of ASPS arising in a vertebra.

Sinais de hipervascularização em imagens de ressonância magnética em metástases ósseas de carcinoma de células renais

OBJETIVO: Avaliar a frequência de hipervascularização pela visualização de vasos no interior ou ao redor de metástases ósseas de carcinoma de células renais. MATERIAIS E MÉTODOS: Foram avaliados, retrospectivamente, exames de ressonância magnética de 13 pacientes com diagnóstico de carcinoma de células renais, com 15 lesões ósseas metastáticas, que não haviam sido submetidos a nenhum tratamento. RESULTADOS: Foram encontrados sinais de hipervascularização em 12 das 15 lesões (80%), sendo 6 na coluna lombar, 3 na bacia, 1 na coluna torácica, 1 na ulna e 1 na tíbia. CONCLUSÃO: A alta frequência de hipervascularização em metástases ósseas de carcinoma de células renais encontrada neste trabalho pode sugerir a etiologia renal, tornando-se muito útil na apresentação clínica usual de lesão óssea única com neoplasia primária desconhecida.

Ultrasonographic and MR findings of alveolar soft part sarcoma

Alveolar soft part sarcoma (ASPS) is a rare soft-tissue sarcoma, commonly occurring in children and adolescents. The tumor mostly involves the lower extremities. The prognosis of the patient depends on whether there is metastasis. We present a 19-year-old female with ASPS in her right lower leg. Grayscale and color Doppler ultrasound showed a well-defined hypoechoic lesion with hypervascularity and very low resistive index (RI). Magnetic resonance imaging revealed iso signal intensity to muscle on T1-weighted images, high signal intensity to muscle on T2-weighted images with signal voids, and good enhancement after gadolinium administration. In a mass with hypervascularity and very low RI on sonography and hypervascularity with flow voids on magnetic resonance imaging, ASPS should be considered.

Primary alveolar soft part sarcoma of fibula demonstrating ASPL-TFE3 fusion: a case report and review of the literature

Alveolar soft part sarcoma is a rare soft tissue tumor typically affecting young adults. These tumors are most often seen in the deep soft tissues of the extremities and patients generally present with advanced disease. Primary bone involvement is extremely rare and has only been reported in seven cases. This is the first case of alveolar soft part sarcoma in bone documenting the ASPL-TFE3 gene product. Herein, we report a rare presentation of alveolar soft part sarcoma presenting as a primary bone neoplasm involving the proximal fibula in a 41-year-old woman.

Alveolar soft part sarcoma: clinical, histopathological, molecular, and ultrastructural aspects

Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor occurring mainly in the adolescents and young adults. Multimodality treatment has not been effective, and excision remains the mainstay of treatment. Histopathologically, it varies little from case to case. It is composed of organoid aggregates of large polygonal cells with vesicular nuclei and abundant granular, eosinophilic cytoplasm, separated by delicate vascular channels. The line of differentiation of this unique tumor is yet undetermined, although recent advances have led to a better understanding of the genetic events underlying the pathogenesis of this tumor. The histopathological, ultrastructural, immunohistochemical, and genetic aspects of ASPS are discussed.

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.

Endometriosis of the superior gluteal nerve

Endometriosis that involves nerves is rare and usually occurs in the pelvis. We describe a case of extra-pelvic endometriosis that involved the superior gluteal nerve. The patient presented with ill-defined buttock and thigh pain and a Trendelenberg gait. MRI demonstrated atrophic changes in the gluteus minimus, gluteus medius and tensor fascia lata muscles indicating involvement of the superior gluteal nerve. MRI showed a mass in the line of the superior gluteal nerve. The mass was hyperintense on STIR and T1-weighted images and did not enhance after intravenous contrast although surrounding edema did enhance. Histological examination of material obtained at open biopsy showed endometriosis. The patient was commenced on hormonal treatment to suppress ovarian activity.

MRI of alveolar soft-part sarcoma

Alveolar soft-part sarcoma (ASPS) is rare. We present a case of a 30-year-old woman with a 6-month history of a palpable mass in her left thigh. MRI showed an 8-cm mass and a satellite nodule at the left gluteus muscle. The main tumor exhibited an isointense signal on T1-weighted images and high-signal-intensity areas with low-signal-intensity scanty solid components on T2-weighted images. MR angiography showed dilated and tortuous veins around the tumor. Histologic findings were compatible with ASPS.

Hibernoma--correlation of histopathology and magnetic-resonance-imaging features in 10 cases

OBJECTIVE, DESIGN AND PATIENTS: Hibernoma is an uncommon, slow-growing, benign soft-tissue tumour resembling brown adipose tissue. The histological appearances are well-documented, but there are relatively few descriptions of the magnetic resonance (MR) imaging features. We report a retrospective comparison of the histological and MR appearances of ten hibernomas of the extremities, classified histologically into lipoma-like [<70% multivacuolated adipocytes (MVAs)] and non-lipoma-like hibernomas (>70% MVAs).

RESULTS

The lipoma-like hibernomas measured 4-27 cm in maximum size. All were well-defined on MR imaging and histology except for one subcutaneous lesion that blended in with surrounding fat histologically. All lesions were isointense with subcutaneous fat on T1- and T2-weighting apart from one lesion that was predominantly slightly hypointense on T1-weighting and predominantly slightly hyperintense on T2-weighting and STIR. Two slightly inhomogeneous lesions contained thin (<5 mm thickness) tortuous vessels. One patient received intravenous contrast, but the lesion did not enhance. The six non-lipoma-like hibernomas measured 2.5-15.5 cm in maximum size and all were unencapsulated. Three were well-defined and three partly ill-defined on MR imaging. There were no significant differences in the MR characteristics of the non-lipoma-like variants. On T1-weighting, the non-lipoma-like hibernomas that contained >90% MVAs were predominantly slightly hypointense to subcutaneous fat. One lesion was isointense with subcutaneous fat, but this lesion only contained from 80-90% MVAs. All non-lipoma-like lesions were slightly hyperintense on STIR but so too were two of the four lipoma-like lesions. Four of the six non-lipoma-like lesions showed marked or moderate inhomogeneity due to thick septa and prominent vessels. Of the two cases that received intravenous contrast, both showed enhancement corresponding to regions of >90% MVAs or prominent vessels within fibrous septa.

CONCLUSIONS

MR imaging has shown some distinguishing features between lipoma-like and non-lipoma-like hibernomas. Lipoma-like hibernomas are usually isointense with subcutaneous fat on T1-weighting, are either homogeneous or slightly inhomogeneous and may contain thin tortuous vascular structures. Non-lipoma-like hibernomas are pre-dominantly slightly hypointense to subcutaneous fat on T1-weighting, often display marked or moderate inhomogeneity with prominent septa and vessels and enhancement is typical. The appearances of non-lipoma-like hibernomas are not diagnostic and may be mimicked by lipoma variants and by well-differentiated liposarcoma or atypical lipoma.