A case of splaying toes caused by Morton’s neuroma indicates early rheumatoid arthritis

AbstractMorton’s neuroma is an entrapment neuropathy of the plantar digital nerve in the intermetatarsal space by a soft tissue tumor, bursitis, or synovitis. The most common location is the third intermetatarsal space, but splaying toes are rare in typical Morton’s neuroma. However, the location, character, and histological findings are different in Morton’s neuroma with rheumatoid arthritis (RA). RA is seen in 40% of patients with Morton’s neuroma, most of which develop during treatment for RA. However, a Morton’s neuroma that precedes the occurrence of RA is rare. The case of a 68-year-old woman with a burning sensation in her third toe and splaying toes at the second intermetatarsal space is reported. A dumbbell-shaped tumour was seen on magnetic resonance imaging and ultrasound. Needle biopsy was performed under ultrasound guidance, and histopathology was negative for malignancy. Morton’s neuroma was diagnosed and treated with an insole and exercise therapy. After 1 month, she developed swelling and ...