Age / Sex : 53 / F

Age / Sex: 53 / F

Chief complaint: A palpable mass of the right index finger

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

* Send Application Answers to In Sook Lee, MD ([email protected])

Courtesy :

amputation neuroma

Discussion

Findings:

1) Plain radiography

- Swelling at the stump of an amputated index finger

2) US

- A hypoechoic nodule with well-defined margins beside the proximal phalangeal shaft of the index finger

- No vascularity in the mass on color Doppler image

Differential Diagnosis: None

Diagnosis: Traumatic neuroma (of proper palmar digital nerve)

Discussion:

Traumatic neuromas develop from a nonneoplastic proliferation of the proximal end of a severed, partially transected, or injured nerve as a result of trauma or surgery. Pain is the most common clinical symptom and is often reproduced with palpation or tapping on the lesion (Tinel sign). A firm soft-tissue mass at a focal pressure site may be apparent.

 Traumatic neuromas have been divided into two major categories based on the anatomic location of the tangled, multidirectional, regenerating axonal mass with respect to the proximal nerve end. Spindle neuromas are internal, focal, fusiform swellings secondary to chronic friction or irritation to a nondisrupted, injured but intact nerve trunk. Lateral or terminal neuromas are the result of severe trauma with partial avulsion, disruption, or total transection of a nerve.

Typically, a fusiform mass or focal enlargement with an entering and exiting nerve (spindle type) or only an entering nerve terminating in a bulbous shape (lateral or terminal type) is identified. Lesions of small nerves may not be detected radiologically or may be seen as a nonspecific soft-tissue mass without an entering nerve. Lesion margins are often well defined, although some irregularity (likely related to multidirectional cell proliferation) has been seen with US.

References:

1. Resnick D. Diagnosis of bone and joint disorders. Saunders, 2002, 4^th ed. p 4232

2. Murphey MD. Imaging of musculoskeletal neurogenic tumors: Radiologic-pathologic correlation. Radiographics 1999:19;1253-1280