A RED FLAG IN SHADES OF GREY: DEDIFFERENTIATED LIPOSARCOMA AND ITS SONOGRAPHIC APPEARANCES
By Gillian McDonald, University College Dublin
Background:
Soft-tissue sarcomas (STSs) are a rare, heterogeneous group of malignancies with approximately 176 cases reported annually in Ireland. Liposarcoma is the most common subtype, typically presenting as a focal soft-tissue mass. Ultrasound is the indicated first-line modality in assessing soft-tissue masses but is limited in providing total characterisation and fully assessing deeper lesions, for which MRI is reserved. Due to a number of factors, STSs may fail to be recognised. Given their poor prognostic outlook and metastatic potential, recognition of clinical and sonographic features is essential to maximise patient outcome. Such features are demonstrated through a case of aggressive dedifferentiated liposarcoma that initially appeared to be more superficial and smaller. Ultrasound added value in its management.
Ultrasound findings:
B-Mode ultrasound demonstrated a lobulated, solid, hypoechoic, heterogeneous mass measuring 9.8x4.2x5.6cm in the anterior thigh muscle compartment. On Colour Doppler and SMVI interrogation, the mass demonstrated internal vascularity, predominantly in peripheral solid components. Central cystic appearances were favoured to represent necrosis. Care was taken by the sonographer to seek and document a targeted clinical history to provide further insight. Sonographic features of the lesion were highly concerning for STS.
Discussion:
Subsequent MRI and histological analysis of core biopsy samples culminated in a diagnosis of high-grade dedifferentiated liposarcoma. Treatment is stage-dependent and will be guided by CT-TAP. Ultrasound is the first-line imaging modality to assess focal soft-tissue mass, although its utility in deeper lesions is inherently limited and total radiological characterisation requires MRI. This case demonstrates the value of ultrasound in assessing such masses and provides an example of larger, deeper masses appearing smaller and more superficial initially.
Conclusion:
Due to their rarity, clinical significance, likely presentation to ultrasound and current poor prognosis, sonographers must be aware of clinical and sonographic red flag features of liposarcoma, highlighted by an acronym in this poster.