Gouty tophi

An extensive lobulated soft tissue mass lesion at the dorsal aspect of first metatarsal, measuring 2 x 5.7 x 3 cm (predominantly hypointense on all the sequences ) demonstrating multiple small loculations , indenting the dorsal cortex of 1st metatarsal bone with reactive bone marrow edema localized to the midshaft of first metatarsal without bony erosions – likely suggestive of gouty tophi

Other possibility would be Hemangioma versus giant cell tumour of the tendon sheath

The mass lesion is slightly crossing the first metatarsophalangeal joint, involving the overlying extensor tendon.