Case 9

A 12-year-old male presented with a modest volar angular deformity at the wrist that interfered with his musical activities as a drummer.
    A: Lateral radiograph of the wrist at initial presentation at age twelve.
An incisional biopsy was interpreted as a benign fibroma, and an intralesional curettage was done.
    B: Follow-up radiographs at one year (age thirteen) demonstrated a similar lesion in the diaphysis of the ulna.
A marginal en bloc excision was done.
    C: Follow-up lateral radiograph of the forearm at age fourteen showed multiple recurrences and a pathologic fracture at the site of the previous ulnar excision.
Over the next six months, the hand and wrist became progressively disabled with both a radial and ulnar nerve palsy.
    D: AP radiograph at that time.
Re-biopsy was done at that point.
    E: A panoramic view from the soft-tissue component between the radius and ulna.
    F: A field from the lesion in the distal ulna.
    G: A field from the recurrence in the distal radius.

Diagnosis: Fibromatosis All of these features confirm the diagnosis of recurrent aggressive fibromatosis. Because of the diffuse infiltrative nature of the lesion and the total disability of the extremity, a below-elbow amputation was done to obtain a wide margin.
    H: Volar aspect of the incompletely dissected amputation specimen showing the extensive lesion invading both the adjacent radius and ulna.
    I: The sagittal surfaces of the bisected specimen of the distal radius show the process has obliterated the volar portion of the physeal growth plate producing the angular deformity.
    J: The sagittal surfaces of the bisected distal ulna again show the infilltrative nature of the process.
    K: A composite of the specimen and radiograph and
    L: A sagittal macrosection show the extent of the intraosseous components. The entire volar compartment was filled with a mass of dense fibrous tissue encompassing the flexor tendons, the radial artery, and the median and ulnar nerves. Microscopic examination showed the same densely collagenized tissue with minimal cellular activity and without atypia. In areas where it interfaced with the adjacent bone there was a permeative destructive border to the lesion. Following his amputation, he was rehabilitated with an upper-extremity prosthesis and resumed his lifestyle as a drummer in a rock band.
    M: Photograph of the patient with his prosthesis four months following amputation.