Mike Bradley Philip Robinson Craig Gerrand Ultrasound screening of lipomatous masses in the trunk and extremity - a BSG guide for ultrasonographers and primary care. Mike Bradley Philip Robinson Craig Gerrand

Introduction Soft tissue masses are common. Sarcomas are rare but it is very important that they are detected early and managed appropriately. Ultrasound screening of soft tissue masses in the trunk or extremity rapid evaluation and identification of soft tissue masses which are not clearly benign. benign masses (usually lipomata) is of great value and reassurance .

Referral guidelines for sarcoma Increasing in size Size more than 5 cm (except subcutaneous lipomas) Painful

Lipomatous tumours Common tumours identified on ultrasound examination. Correct interpretation and onward referral is important to avoid causing anxiety to patients and overloading sarcoma services. The vast majority of lipomatous tumours are benign and the 5cm size criterion is not relevant for subcutaneous lipomatous tumours. IS IT RELEVANT FOR DEEP LIPOMAS?

Ultrasound technique for evaluation of soft tissue masses The following are recommended for USS of soft tissue masses: Scans should be performed or supervised by a clinician who is FRCR or RCR accredited to perform and report ultrasound (preferably musculoskeletal ultrasound). A clinical history should be taken, including details of size, duration, precipitants, growth, and associated symptoms. A clinical examination of the mass for position and local changes should be performed. The ultrasound machine used must be of diagnostic/medical standard with at least 6 monthly quality assurance of electrical safety, transducer, machine and monitor quality.

Ultrasound technique for evaluation of soft tissue masses Ultrasound should be performed on a high resolution scanner with a linear high frequency probe, typically up to 15/18 mHz, depending on the anatomical location. Ultrasound examination should evaluate mass size, mass location (relationship to fascia), echotexture, whether cystic, solid or mixed, and Doppler characteristics (at low flow settings). If the scan is diagnostic of a non sarcomatous mass (benign) (figure 1) then report to GP. If the scan is diagnostic of a non sarcomatous mass (malignant) by history and appearances – report to GP and refer to local oncology service. If the scan is diagnostic for lipoma but there are concerning symptoms (figure 1) – report to GP and perform MRI (notify sarcoma service – non urgent). If the scan is suspicious for sarcoma or indeterminate (figure 1)–report to GP and perform MRI (notify sarcoma service - urgent).

Flow chart for the ULTRASOUND assessment of LIPOMATOUS soft tissue masses

IMAGING GUIDE FOR LIPOMATOUS TUMOURS *Imaging Benign Lipoma Homogeneous lesion No or septal linear power Doppler flow No or thin (<2mm) septa

IMAGING GUIDE FOR LIPOMATOUS TUMOURS **Potentially Aggressive Lipoma   Lipoma but very heterogeneous or Lipoma but very thick septa (>2mm) or Nodular non lipomatous area(s) or Disorganised power Doppler flow or Invasive margins

IMAGING GUIDE FOR LIPOMATOUS TUMOURS ***Indeterminate/Aggressive Mass (non lipoma)   Solid non lipoma or Heterogeneous mass or Disorganised power Doppler flow or Invasive margins

IMAGING GUIDE FOR LIPOMATOUS TUMOURS # Non-urgent referral outcome; MDT/clinic review and Discharge back to GP or Requires surgery or Requires biopsy or Requires imaging follow-up – once at 6 months

References [1] Rowbotham E, Bhuva S, Gupta H, Robinson P. Assessment of Referrals into the Soft Tissue Sarcoma Service: Evaluation of Imaging Early in the Pathway Process. Sarcoma 2012;2012:1–5. doi:10.1155/2012/781723. [2] Lakkaraju A, Sinha R, Garikipati R, Edward S, Robinson P. Ultrasound for initial evaluation and triage of clinically suspicious soft-tissue masses. Clin Radiol 2009;64:615–21. doi:10.1016/j.crad.2009.01.012. [3] Dangoor A, Seddon B, Gerrand C, Grimer R, Whelan J, Judson I. UK guidelines for the management of soft tissue sarcomas. Clin Sarcoma Res 2016;6:20. doi:10.1186/s13569-016-0060-4.