Figure 2b. Deep infiltrating intramuscular lipoma of the calf in a 17-year-old boy with a palpable soft-tissue mass. (a) Axial T1-weighted (600/12) MR image shows a mass isointense relative to subcutaneous fat that infiltrates the soleus muscle (arrows) and extends across the intermuscular planes to more mildly involve other calf muscles (arrowheads). (b) Photograph of the axially sectioned gross specimen reveals infiltrating lipoma (black *) extensively interdigitating with the soleus muscle (white *).