Question

A 65-year-old male presents to the Orthopedic Oncology clinic for a plantar soft tissue mass of his left foot for the past 2 years. Additional history reveals several preceding and ongoing years of atraumatic rib, back, and bilateral lower leg pain (Fig. 1).

Fig. 1
figure 1

A Coronal T1-weighted MR image of the right knee. B Maximum-intensity-projection (MIP) image of 68 Ga-DOTA-TOC-PET/CT-scan. C Short axis T1-weighted fat-suppressed post-contrast MR image of the left forefoot. D Histology. Hemotoxylin and eosin stain at 100 ×