Imaging Features of Primary Alveolar Soft Part Sarcoma of the Parotid Gland

Abstract Context Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor most commonly occurring in deep intramuscular plane of lower extremities of adolescents and young adults. It is a highly vascular, slow growing tumor with malignant potential having lung as the most common site of metastases at the time of presentation. Aims The aim is to review the imaging findings of ASPS and determine characteristic imaging features of this rare tumor. Materials and Methods Sixteen patients having histopathological diagnosis and preoperative imaging of ASPS attending the dedicated sarcoma clinic at our institute were included in the study. The demographic, clinical, and imaging data were retrieved from the case records and then evaluated for characteristic imaging features which may raise suspicion of ASPS. Results The patients ranged from 3 to 72 years of age and with a slight male preponderance. Of the eight CECTs evaluated, 62.5% tumors showed well-defined lobulated margins, 87.5% cases showed intense enhancement with presence of feeder vessels. On CEMRI of 10 patients, 70% had well circumscribed lobulated margins with intense enhancement and tortuous flow voids in most of them. All cases showed T2 hyperintense signal. Fourteen of 16 (87.5%) patients had metastatic disease with lung as the most common site (92.8%). Conclusion ASPS is a rare soft tissue sarcoma seen in children and young adults. Imaging may mimic a vascular malformation due to the presence of tortuous feeders. Misdiagnosis at an early stage may lead to later metastatic presentation of the disease, thus emphasizing the need to suspect it on imaging.

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

Cancer Imaging ◽

10.1186/s40644-020-00352-9 ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Naami Charlotte Mcaddy ◽

Hind Saffar ◽

Saskia Litière ◽

Pieter Jespers ◽

Patrick Schöffski ◽

...

Keyword(s):

Pulmonary Metastases ◽

Soft Part ◽

Primary Tumour ◽

High Rate ◽

Alveolar Soft Part Sarcoma ◽

Imaging Features ◽

Antiangiogenic Treatment ◽

Feeding Vessels ◽

Slow Growing ◽

Sites Of Metastases

Abstract 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.

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