Calcifying Aponeurotic Fibroma of the Hand: Radiologic Differentiation from Giant Cell Tumors of the Tendon Sheath

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Discussion

10nctate densities were visible within the mass sug-stive of a chondroid matrix.A high-resolution magnetic resonance imageRI) of the hand was obtained with and without

dolinium. The examination showed a heteroge-ously enhancing soft-tissue mass at the ventralse of the fifth metacarpophalangeal joint abuttingd lying anterior to the flexor tendon. The massasured 2.4 (length) 1.2 (anteroposterior) 1.5

Calcified aponeurotic fibroma is a rare benign soft-tissue tumor with intermediately aggressive bio-logic behavior. Now classified within the group ofsuperficial musculoskeletal fibromatosis1 these le-sions first were described in 1953 by Keasbey2 ascalcifying juvenile aponeurotic fibromas becausethey were believed to occur only in the first andsecond decades of life. Now over 80 cases havebeen described in the literature3; the mean age ofCalcifying AponeurHand: Radiologic D

Giant Cell Tumors oWendy L. Parker, MD, PhD,

Kimberly K.

From the Departments of Orthopedic Surgery

n 11-year-old, healthy, right-handdominantboy presented with a 2-year history of aslow-growing mass in the palm of the left

nd. There was a vague history of possibly a remotelinter in the area but no other reported trauma. Thess was painless apart from mild discomfort withect pressure noted while gripping. The patientnied any local neurologic symptoms and was oth-

ise systemically well without fevers or other con-tutional features.Physical examination showed a nontender, firmss measuring 2 2 cm overlying the volar aspectthe fifth metacarpal head in the palm (Fig. 1). Theerlying skin was unremarkable, nonadherent, andthout identifiable punctures sites or dimpling.ansillumination showed a slightly less translucenta compared with the surrounding tissue and thesence of a prominent vessel along the ulnar aspectthe mass. Two-point discrimination was 4 mmoughout the hand. Normal strength and motionre noted without evidence of joint contracture.e mass appeared fairly well encapsulated and didt move with the overlying flexor tendons; how-er, it was fixed firmly to the underlying soft tissues.Radiographs were obtained in the anteroposteriord lateral positions (Fig. 2). A soft-tissue mass wasntified along the palmar and radial aspects of the24 The Journal of Hand Surgeryc Fibroma of theerentiation frome Tendon Sheathrt R. Beckenbaugh, MD,mi, MD

adiology, Mayo Clinic, Rochester, MN.

idth) cm. The mass was lobulated and of interme-te signal intensity on both T1- and T2-weightedaging (Fig. 3). There was also evidence of a fewernal fatty septations and tiny speckled areas of

signal corresponding to the punctate calcificationsent on the plain films.

Differential diagnosis of this soft-tissue mass in-ded benign lesions such as a soft-tissue chon-ma and giant cell tumor (GCT) of the tendon

eath. Less likely this mass could represent a ma-nant process such as a soft-tissue sarcoma. Be-use of the slow-growing nature and benign radio-phic appearance of the mass we elected to proceed

th excisional biopsy. Under general anesthesia andrniquet a longitudinal incision was made, showingencapsulated mass that was not adherent to the

in but adherent to the surrounding fatty and fibroussue. The mass was rising from the flexor sheathd the fascia over the interosseous muscles. Thertion of the flexor sheath was excised progres-ely, incorporating the mass and the fascia over theial lumbrical until the mass was excised com-tely (Fig. 4). Intraoperative frozen section showed

calcified aponeurotic fibroma. Margins were ex-ed until free from tumor, leaving the tendon un-vered from the proximal end of the A2 pulley areathe palmar region. The postoperative course was

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Parker, Beckenbaugh, and Amrami / Calcified Aponeurotic Fibroma Differentiation 1025set is 12 years but there are documented casesm birth4 to 64 years.5These tumors have a predilection for the palms,gers, and soles of the feet,2 with males affectedre than twice as commonly as females.5 The

Figure 1. Photographic views of the left p

ure 2. Radiographs of the left hand. (A) The anteroposteriorMCP interspace. (B) On lateral view the mass is visible with etrix (arrow).ical presentation is that of a slow-growing,ymptomatic mass. It has been reported that 67%

these arise in the deep palmar fascia of thend.5,6 They rarely measure more than 3 cm inmeter and have never been reported as being

ass. (A) Anteroposterior, (B) lateral.

monstrates a soft tissue density centered over the 4th andce of multiple punctate densities suggestive of a chondroidfilm devidentypas

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1026 The Journal of Hand Surgery / Vol. 31A No. 6 JulyAugust 2006herent to skin or associated with joint contrac-es.7

The recurrence rate after surgical excision isorted generally as 50%6 and the tumor-freeerval ranges from 6 months to 23 years.5,8,9 Thiscessitates an accurate diagnosis and completecision. Gross pathology is that of a flesh-coloredulated mass with pseudoencapsulation or anltrative margin. Microscopically the tumors are

mposed of spindle-shaped fibrous cells that areparated and surrounded by abundant collagenterial with rare mitoses.1 Diffuse background

ure 3. High-resolution magnetic resonance images (MRI) ohancing soft-tissue mass at the ventral base of the fifth metadon. The lobulated mass demonstrates a few internal fatty sepunctate calcification present on the plain films.

ure 4. Intra-operative photographic views of the left palm mt was not adherent to the skin but adherent to the surroundd the fascia over the interosseous muscles. (B) The portion oss and the fascia over the radial lumbrical until the mass wining with S-100 protein is thought to be non-ecific, although definite staining for smooth-scle actin and other elements is noted on Mas-

n trichrome staining.7 Scattered foci ofondroid differentiation are a distinguishing fea-e.5,10 Recently, cytologic features have beenorted11 and suggest that diagnosis with fine-

edle aspiration biopsy is possible to aid in dif-entiation from soft-tissue sarcomas.Radiographs show a nonspecific soft-tissue masst may show finely stippled calcifications and oc-

sional scalloping of the adjacent bone.2,6,12 Calci-

and T1- (A) and T2- (B) images show a heterogeneouslyphalangeal joint abutting and lying anterior to the flexorns and tiny speckled areas of low signal corresponding to

A) A longitudinal incision exposed an encapsulated massty and fibrous tissue. It was arising from the flexor sheathexor sheath was excised progressively, incorporating theised completely.ass. (ing fatf the flas excstaspmu

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Parker, Beckenbaugh, and Amrami / Calcified Aponeurotic Fibroma Differentiation 1027ation observed radiologically, however, is not ansistent feature11 and can complicate the diagnosisd raise the suspicion of other benign soft-tissue orlignant tumors. Moreover 2 patients12,13 withique bony involvement have been reported.Magnetic resonance imaging may show a lobu-ed soft-tissue mass with adherence to surroundinguctures. Prominent low to intermediate signal in-sity and bands of low signal intensity representinghly collagenized tissue is characteristic of fibro-tosis on T1 images.1Magnetic resonance imaging of our patient leda differential diagnosis of benign soft-tissueors including hemangioma, soft-tissue chon-

oma, or a GCT of the tendon sheath and lessely a malignant process such as a soft-tissuercoma. Giant cell tumor of the tendon sheath is

second most frequent hand tumor, typicallyund in the fingers in the second to fourth de-des. These are painless, lobulated masses that

ure 5. A sagittal MRI of our patient illustrates distinguish-characteristics of a calcified aponeurotic fibroma, includ-heterogeneous enhancement, speckled calcifications,

d ill-defined margins.ciated intimately with the tendon sheath, arisingquently at the level of the joints. They canltrate the overlying dermis14 and may erode

ne by pressure15 or frank invasion.16 The pre-ntation of our patient shared features of both

T and calcified aponeurotic fibroma clinicallyd radiologically. Because of the common natureGCT of the hand, the anatomic location of theor in our patient, and its association with the

xor tendon sheath, however, this was the pre-med preoperative diagnosis. Careful review of

MRI scans showed distinguishing characteris-s of each lesion that may have permitted the

ure 6. Giant cell tumor of the tendon sheath has a char-eristic MRI appearance with lobulated, well-defined mar-s; close association with the tendon sheath; and uniformhancement after contrast administration. Pressure erosionsadjacent bones are common but calcifications are verye.

prospective diagnosis of calcified aponeurotic fi-broma, including heterogeneous