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

Abstract

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 Actcompliant 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 5) were well circumscribed, compared with skeletal muscle, were isodense on CT, hyperintense on T 1 and T 2 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 5 8) and 60 months for those with brain metastases (n 5 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.

Magnetic Resonance Features and Characteristic Vascular Pattern of Alveolar Soft-Part Sarcoma

“…ASPS is a rare type of sarcoma that accounts for approximately 0.5-1.0% of all soft-tissue sarcomas [7]. The most common sites of ASPS are the deep muscles of the lower limbs.…”

Soft Tissue Tumors in Adults: ESSR-Approved Guidelines for Diagnostic Imaging

“…Osseous metastases occur in 10% of soft tissue sarcoma patients. 46 Higher incidences have been described for alveolar soft part sarcomas, 47,48 angiosarcomas, 47 leiomyosarcomas, 49 undifferentiated pleomorphic sarcomas, 46 and dedifferentiated liposarcomas. 47 Eighty percent of those osseous metastases are lytic, 46 and fluorodeoxyglucose (FDG)-PET may be useful in these tumors.…”

Current Concepts in Non-Gastrointestinal Stromal Tumor Soft Tissue Sarcomas: A Primer for Radiologists

“…Papillary renal cell cancer is an example of a c-Met driven carcinoma, and targeted inhibitors have shown promising results in early trials (7980). Alveolar soft part sarcoma, an uncommon tumor of the extremities in adolescent with a high incidence of pulmonary and brain metastases (81) has the t(X; 17) translocation activating the microphthalmia transcription factor (MIF) and the c-Met pathway. Clear cell sarcoma is another example of an MIF-driven tumor (82).…”