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Acute Median-Nerve Compression Caused by Calcifying Aponeurotic Fibroma

Kim, Dong Hwee MD, PhD; Hwang, Miriam MD, PhD; Lee, Jung Ill MD; Park, Jong Woong MD, PhD

American Journal of Physical Medicine & Rehabilitation: December 2006 - Volume 85 - Issue 12 - p 1017-1018
doi: 10.1097/01.phm.0000247781.86876.3e
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From the Departments of Rehabilitation Medicine (DHW, MH) and Orthopaedic Surgery (JIL, JWP), College of Medicine, Korea University, Seoul, Korea.

All correspondence and requests for reprints should be addressed to Jong Woong Park, MD, PhD, Department of Orthopaedic Surgery, Korea University Ansan Hospital, 516, Gozan Dong, Ansan City, Gyeonggi Province, Korea.

A 38-yr-old female patient presented with right wrist pain combined with numbness and a tingling sensation in the sensory territory of the median nerve. The symptoms had occurred 3 mos previously and had rapidly progressed thereafter. Mild tenderness was noted on the volar aspect of the wrist. Tinel's sign and the straight arm–raising test were positive. Phalen's test was difficult to perform because of her pain on wrist motion. Routine nerve-conduction studies indicated a mild degree of median-nerve neuropathy, whereas the needle electromyograph findings were unremarkable. Inching test using TenElectrodes1 localized the lesion to the nerve segment of 1–2 cm distal to the distal wrist crease. Sonography performed after electromyography revealed a hyperechoic mass between the flexor tendons and the wrist-joint capsule. Radiographs showed an oval-shaped calcified mass in the carpal tunnel (Fig. 1). Magnetic resonance imaging showed a well-marginated intermediate signal mass measuring 17 × 10 × 5 mm in size (Fig. 2). On the operation, division of the transverse carpal ligament revealed localized fatty degeneration of the median nerve at the same segment where the electromyograph had indicated. A yellowish white mass compressing the median nerve was identified under the flexor tendons. The mass was completely removed and thoroughly curetted from the surrounding tissue. The histology was compatible with a calcifying aponeurotic fibroma (CAF).





Acute median-nerve compression neuropathy caused by a space-occupying lesion is a relatively rare condition, generally occurring as a unilateral lesion. Although several tumorous conditions have been reported as causes of median-nerve compression, CAF has not been described before. CAF is an unusual soft-tissue neoplasm that typically occurs in the hands and feet of children and young adults.2 Although there have been reports of CAF in the wrist,3,4 our case indicates that a rapidly developing CAF around the wrist can cause acute median-nerve compression by increasing the compartment pressure within the carpal tunnel. The histology in this case revealed interlacing bundles of spindle cells with plump nuclei, and there were foci of chondroid differentiation that are the distinctive characteristics of a typical CAF. Electrophysiologic studies can generally confirm median-nerve neuropathy, and simple transverse carpal ligament release is a traditionally accepted operative procedure. However, median-nerve compression caused by a space-occupying lesion might be easily overlooked, and so performing only release of the transverse carpal ligament may not completely resolve the patient's problem. Because the conventional electrophysiologic study has a limitation for detecting a deep-seated mass that may compress the nerve, sonography has a special value as an adjunctive screening method along with electrophysiologic study for making the diagnosis of carpal tunnel syndrome. Magnetic resonance imaging can be used to make a stronger tentative diagnosis before the operation if the sonography detects an unexpected space-occupying lesion. Our case indicates that for cases of carpal tunnel syndrome that are diagnosed by electrophysiologic study, plain radiographs and sonography may be routinely performed to rule out the possibility of a mass lesion.

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1. Kang YK, Kim DH, Lee SH, et al: Tenelectrodes: a new stimulator for inching technique in the diagnosis of carpal tunnel syndrome. Yonsei Med J 2003;44:479–84
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4. Goldman RL: The cartilage analogue of fibromatosis (aponeurotic fibroma). Further observations based on 7 new cases. Cancer 1970;26:1325–31
© 2006 Lippincott Williams & Wilkins, Inc.