A benign perineuralfibroma of an intermetatarsal plantar nerve.
Most commonly affects the third and fourth intermetatarsal space
Patient's will often complain of pain and/or numbness in the ball of their foot and toes when the metatarsal heads are compressed together as in when wearing shoes. Pain is often described as burning or shooting. Some patients report that it feels like they are standing on a pebble.
On physical exam you can reproduce the pain by squeezing the metatarsal heads together. (Mulder's sign)
Diagnosis can be confirmed with MRI though clearly this does not need to be done in the ED.
Treatment includes NSAIDs and referral for orthotics, corticosteroid injection, or surgical removal.
References
Thomas JL, et al. Diagnosis and treatment of forefoot disorders: Morton's intermetatarsalneuroma. Journal of Foot and Ankle Surgery. 2009;48:251.
