Figure 2: Axial T1W MRI image of the neck at the level of the thyroid gland showing a unilateral left posterior triangle mass. Its medial aspect comprises a triangular shaped T1W hypointense structure (white arrows) that is compatible with muscle tissue. Its lateral aspect comprises a rounded T1W hyperintense structure (black arrows) that has similar signal to the surrounding fat and is suggestive of a lipomatous component. A couple of muscle fibres are also present centrally within the lipomatous component (arrowheads).