ACR Codes: 4.3
Morton’s neuroma is a non-neoplastic perineural fibrosis of an interdigital nerve. It most commonly involves the lateral branch of the medial plantar nerve between the third and fourth metatarsal heads. Less commonly involved are the second and fourth interspaces. Female to male ratio is 18:1 and usually occurs between ages 40 – 60. Patients often present with pain and tenderness in the involved interspace. Mechanism of pain is thought to be compression of the nerve against the intermetatarsal ligament. Absence of a palpable mass is frequent.
Radiographic evaluation is usually normal. Anecdotal experience of Kransdorf and Murphey suggests that power Doppler sonography is a valuable adjunct, with lesions typically showing increased vascularity. T1 and T2-weighted MRI images usually demonstrate a low to intermediate signal intensity mass between the plantar aspects of the metatarsal heads. Conspicuity of the lesion is reduced on T2 weighted images, making differentiation between lesion and surrounding fat and muscle difficult. The most sensitive technique for depicting these lesions is fat-suppressed contrast enhanced images. In most cases, however, coronal T1 weighted images reveal the lesions. According to Stoller, this technique displays lesion hyperintensity in cases where conventional T2-weighted images either fail to demonstrate the lesion or show the lesion with decreased conspicuity.
The most successful treatment modality is excision of the neuroma and involved nerve segment. Other treatment options include neurolysis, steroid injection, ultrasound therapy, and surgical release of the transverse metatarsal ligament for decompression.
Reference(s): Kransdorf, Mark J. and Murphey, Mark D. Imaging of Soft
Tissue Tumors. Philadelphia: W.B. Saunders Company,
1997.
Stoller, David W. Magnetic Resonance Imaging in
Orthopaedics and Sports Medicine: 2nd edition.
Philadelphia: Lippincott-Raven, 1997.
Use this for Comments and SuggestionsMedPix® is sponsored by the Department of Radiology and Radiological Sciences, USUHS, Bethesda, MD We do not accept paid advertisements.
Disease Topic 3546 
Click Here for MedPix®-2
for Comments and Suggestions
