Journal of Hand Surgery
Volume 29, Issue 1 , Pages 148-153, January 2004

Intraneural nodular fasciitis: case report and literature review1

  • John H Mahon, MD

      Affiliations

    • South Bend Orthopaedic Surgery, South Bend, IN, USA
    • Corresponding Author InformationReprint requests: John H. Mahon, MD, South Bend Orthopaedic Surgery, 53880 Carmichael Dr, South Bend, IN 46635, USA
    • ,
  • Andrew W Folpe, MD

      Affiliations

    • Department of Pathology, Emory University, Atlanta, GA, USA
    • ,
  • Randolph J Ferlic, MD

      Affiliations

    • South Bend Orthopaedic Surgery, South Bend, IN, USA

Received 23 April 2003; received in revised form 8 September 2003; accepted 8 September 2003.

Article Outline

Abstract 

Nodular fasciitis is a benign or reactive myofibroblastic soft tissue tumor that occurs most frequently in the forearm but has been reported throughout the body. Nodular fasciitis has not been reported to arise within a peripheral nerve, and we present a case of intraneural nodular fasciitis within the ulnar nerve at the distal forearm. Preoperative symptoms of advanced ulnar neuropathy resolved completely after intraneural dissection and subtotal resection of the tumor.

Keywords:  Nodular fasciitis, intraneural tumor, pseudosarcoma

 

Nodular fasciitis is an unusual myofibroblastic tumor that most commonly presents in the subcutaneous fat of the forearm but may occur anywhere throughout the body.1, 2, 3 The diagnosis is rarely made preoperatively, although a rapidly growing mass in the forearm is suggestive.4, 5 We report a case of intraneural nodular fasciitis arising within the ulnar nerve in the distal forearm. To our knowledge this is the first reported case of the tumor arising within a nerve. Interfascicular dissection and subtotal tumor resection fully relieved the patient’s preoperative symptoms of ulnar neuropathy.

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Case report 

A 32-year-old mechanic complained of inability to adduct his right small finger and decreased sensibility in the small finger and the ulnar aspect of the ring finger. Symptoms had been present for 6 weeks and were temporally associated with the presence of a painless mass in the volar ulnar forearm just proximal to the wrist flexion crease. There was no history of trauma or overuse.

Physical examination showed a 4 cm × 3 cm soft tissue mass in the forearm just radial to the flexor carpi ulnaris tendon—and proximal to Guyon’s canal. The mass was nontender and palpation did not elicit paresthesias. It was firm, mobile, and not adherent to the overlying skin. There was weakness of the ulnar-innervated musculature in the hand and diminished sensibility in the small finger and the ulnar aspect of the ring finger. Wartenberg’s and Froment’s signs were both present and there was slight wasting of the first dorsal interosseous muscle.

Electrodiagnostic studies were obtained and confirmed an ulnar neuropathy distal to the soft tissue mass. There was a demyelination injury at the level of the soft tissue mass, which was thought to be due to compression. The ulnar sensory latency was slowed at 5.4 milliseconds with normal amplitude. The ulnar motor nerve showed increased distal latency, slightly decreased amplitude, and a decreased conduction velocity. There was no significant drop in amplitude or conduction velocity above the baseline impairment levels when the ulnar nerve was assessed across the elbow. Electromyographic results were normal.

Magnetic resonance imaging scan showed a soft tissue mass deep to the flexor carpi ulnaris muscle and tendon that measured 1.7 × 1.1 × 2.5 cm. The mass was of intermediate signal intensity on -weighted images and of considerably increased signal intensity on T2-weighted images. The lesion was thought to be a solid, septated tumor arising from the ulnar nerve and was believed most consistent in magnetic resonance imaging appearance with neurofibroma or schwannoma Figure 1, Figure 2.

The patient was brought to the operating room for surgical resection, and the mass was found intimately associated with the ulnar nerve (Fig. 3). It lay within the fascicles (Fig. 4) and required intraneural (fascicular) dissection under magnification, and it was mostly though not completely removed (Fig. 5). It measured 2.5 × 1.6 × 2.5 cm and had a tannish brown appearance.

Histologic evaluation of the specimen showed typical features of nodular fasciitis, with short, randomly distributed fascicles of normochromatic myofibroblasts, microcystic change, extravasated red blood cells, and scattered chronic inflammatory cells (Fig. 6). Histologic features of benign peripheral nerve sheath tumors such as schwannoma and perineurioma, namely thick-walled blood vessels and nuclear palisading and concentric “onion bulb” formations, were entirely absent. Smooth muscle actin immunostain showed positivity in a “tram-track” pattern typical of myofibroblasts. An S100 protein immunostain was negative in the lesional cells and did not show any entrapped nerve fibers. Epithelial membrane immunostain was negative.

The patient experienced immediate postoperative pain relief and recovered full sensation and motor function within the first postoperative week. The tumor has not recurred.

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Discussion 

Nodular fasciitis is a benign connective tissue tumor that usually presents as a painless, rapidly growing subcutaneous mass. Konwaler6 presented the first report of this lesion as a singular entity and called it subcutaneous pseudosarcomatous fasciitis because of its histologic resemblance to sarcoma and the confusion regarding its diagnosis. It has also been known as infiltrative fasciitis, nodular fibrositis, and subcutaneous fibromatosis. Subsequent studies showed that the lesion may present throughout the body and is not restricted to the subcutaneous tissues; thus the accepted terminology for this lesion is now nodular fasciitis.1, 2, 5, 6

Most patients present for treatment within 8 weeks of first noticing a rapidly growing soft tissue mass. Nodular fasciitis most commonly involves the subcutaneous fat of the forearm but may present in virtually any somatic soft tissue site and may occur in suprafascial, intrafascial, and subfascial locations.7, 8, 9, 10 Although classic nodular fasciitis does not involve the viscera, histologically identical myofibroblastic proliferations may occur in a variety of intra-abdominal and visceral locations, such as the bladder and omentum. Because of its sometimes high cellularity, infiltrative growth pattern, and brisk mitotic activity, nodular fasciitis can be mistaken for a sarcoma.3, 11

The etiology of nodular fasciitis is uncertain. Although some cases, particularly in children, show a clear association with recent trauma, a history of trauma is absent in most cases of fasciitis. More recently, clonal chromosomal abnormalities have been reported in a small number of cases, suggesting that at least some cases of nodular fasciitis may represent a clonal myofibroblastic tumor.12, 13 In 1 recently reported case, the tumor arose at the site of a tick bite and contained Borellia afzelii–specific deoxyribonucleic acid, suggesting an infectious etiology.14 There is also a report of biopsy-proven nodular fasciitis resorbing completely after intralesional injection of corticosteroid, which suggests an inflammatory etiology.15

Nodular fasciitis typically presents as a circumscribed but nonencapsulated, variably myxoid, tan-colored mass. Histologically classic lesions are composed of short, randomly arranged fascicles of cytologically bland myofibroblastic cells, arranged in what resembles a tissue culture pattern. Unlike true sarcomas, they lack a well-developed vasculature and typically undergo microcystic change with extravasation of red blood cells. Mitotic figures are easily identified. Occasional cases of nodular fasciitis show marked hypercellularity, stromal hyalinization, osteoclast-like giant cells, intravascular growth, and even necrosis, further simulating a malignant soft tissue neoplasm.1, 2, 3, 4, 5, 6 By immunohistochemistry, nodular fasciitis shows myofibroblastic differentiation, with peripheral cytoplasmic (“tram-track”) smooth muscle actin expression, variable desmin expression, and, rarely, focal expression of other proteins such as cytokeratins and collagen type IV.16

Given the intraneural location of this case, the differential diagnosis is principally with benign nerve sheath neoplasms, such as schwannoma, neurofibroma, perineurioma, and malignant peripheral nerve sheath tumors. Nodular fasciitis may be distinguished easily from schwannoma by the absence of a capsule, thick-walled blood vessels, Verocay bodies, and S100 protein expression. Similarly, neurofibroma contains characteristic shredded-carrot collagen and expresses S100 protein. Intraneural perineuriomas display diagnostic “onion bulb”–like formations and express epithelial membrane antigen. Malignant peripheral nerve sheath tumors are usually obviously sarcomatous, with long fascicles of hyperchromatic spindled cells, abnormal mitotic figures, and frequent geographic necrosis. Although ultrastructural study may be occasionally valuable in the diagnosis of unusual nerve sheath tumors, with schwannomas typically showing reduplicated basal lamina and long-spacing collagen and perineuriomas showing long cellular processes, tight junctions, and incomplete basal lamina, this technique is used seldom, if ever, in the diagnosis of nodular fasciitis. By electron microscopy, the cells of nodular fasciitis resemble typical myofibroblasts and fibroblasts, with an abundant rough endoplasmic reticulum and occasional dense bodies. Awareness of the histologic spectrum of nodular fasciitis and of its ability to occur in usual locations (eg, intraneural) is the key to avoiding misdiagnosis, which could cause serious harm to the patient.11

A considerable responsibility in the treatment of nodular fasciitis lies with the pathologist, who must distinguish this benign, yet infiltrative and mitotic, lesion from sarcoma. Even subtotal resection of nodular fasciitis leads to symptomatic relief, so the surgical treatment is generally successful and gratifying. Pathologic misdiagnosis, however, may lead to unnecessarily aggressive surgical treatment. Intralesional injection of large nodular fasciitis lesions has resulted in resolution of the mass, but the diagnosis cannot be reached without an initial surgical biopsy.

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References 

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  2. Bernstein KE, Lattes R. Nodular (pseudosarcomatous) fasciitis, a nonrecurrent lesion (clinicopathologic study of 134 cases). Cancer. 1982;49:1668–1678
  3. Shimizu S, Hashimoto H, Enjoji M. Nodular fasciitis (an analysis of 250 patients). Pathology. 1984;16:161–166
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  5. Culberson JD, Enterline HT. Pseudosarcomatous fasciitis (a distinctive clinical-pathologic entity; report of five cases). Ann Surg. 1960;151:235–240
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  8. Brimhall CL, Segura AD, McTigue MK, Easterly NB. Nodular fasciitis on the palm of a child. Arch Dermatol. 1989;125:1441–1442
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  12. Donner LR, Silva T, Dobin SM. Clonal rearrangement of 15p11.2, 16p11.2, and 16p13.3 in a case of nodular fasciitis (additional evidence favoring nodular fasciitis as a benign neoplasm and not a reactive tumefaction). Cancer Genet Cytogenet. 2002;139(2):138–140
  13. Velagaleti GV, Tapper JK, Panova NE, Miettinen M, Gatalica Z. Cytogenic findings in a case of nodular fasciitis of subclavicular region. Cancer Genet Cytogenet. 2003;141(2):160–163
  14. Schnan S, Wahl A, Jurgens-Saathoff B, Mengel M, Kreipe HH, Zeidler H. Nodular fasciitis, erythema migrans, and oligoarthritis manifestations of Lyme borreliosis caused by Borrelia afzelii. Scand J Rheumatol. 2002;31:184–186
  15. Graham BS, Barrett TL, Goltz RW. Nodular fasciitis (response to intralesional corticosteroids). J Am Acad Dermatol. 1999;40:490–492
  16. Folpe AL, Gown AM. Immunohistochemistry for analysis of soft tissue tumors. In:  Goldblum JR,  Weiss SW editor. Soft tissue tumors. (4th ed).. St. Louis: Mosby; 2001;p. 199–246
  • 1 No benefits in any form have been received or will be received by a commercial party related directly or indirectly to the subject of this article.

PII: S0363-5023(03)00491-X

doi:10.1016/j.jhsa.2003.09.001

Journal of Hand Surgery
Volume 29, Issue 1 , Pages 148-153, January 2004

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