Case 8 -

Nodular Fasciitis Syed Z. Ali The Johns Hopkins Hospital Baltimore, MD

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Clinical History 35 year-old man with left lower chest wall pain for one year, who has noticed a slowly growing mass for two months. Radiologically-guided (ultrasound) FNA of the 2.5 cm soft tissue mass (left lateral lower chest wall). Case 8 - Figure 1 Diff Quik Stain, X100 Case 8 - Figure 2 Diff Quik Stain, X200 Case 8 - Figure 3 Papanicolaou Stain, X200 Case 8 - Figure 4 Diff Quik Stain, X200 Case 8 - Figure 5 Diff Quik Stain, X400 Cytologic Diagnosis: Nodular Fasciitis. Histologic Diagnosis: Nodular Fasciitis. Cytologic Findings: Smears are hypercellular and comprised of predominantly large irregular tissue fragments with jagged or feathery outer edges. These fragments seem to be associated with a loose myxomatous stroma which is scant and identifiable only on closer examination. Higher magnification additionally reveals numerous discohesive single cells with well-formed fusiform morphology i.e., plump cigar shaped nuclei and long bipolar cytoplasmic tails. On Papanicolaou stained smears, an elaborate arborizing capillary network is seen intimately associated with the proliferating mesenchymal cells with stellate shapes, tapering nuclei and fine wispy cytoplasmic processes. Some tissue fragments also display a loose storiform pattern. Occasional strands of keloid-like fibrous tissue are also noted. Histologic and Clinical Follow-up: The indications for removal i.e., pain and discomfort, and the potential for continued growth were discussed with the patient. He was very eager to have this removed. Under general endotracheal anesthesia, the lesion was removed with the surrounding tissue. Grossly, the specimen consisted of an irregular mass of connective tissue and skeletal muscle which measured in aggregate 6.0 x 4.0 x 4.5 cm. On cut section, a nodular poorly circumscribed white firm area was identified which measured 3.5 x 3.0 x 2.5 cm. Histologic examination showed "NODULAR FASCIITIS. LESION PRESENT AT THE DEEP SPECIMEN MARGIN OF RESECTION". Last clinical follow-up was in September 2006. He was noted to be doing fairly well. Discussion: Nodular fasciitis (NF), also known as "pseudosarcomatous fasci itis" is a benign tumefactive pro liferation of fibroblasts and myofibroblasts and is a well-known member of the family of pseudotumors. The lesional cells in NF are reactive rather than neoplastic. It is a self-limited reactive process that manifests as a readily palpable mass-forming lesion. NF comes to clinical attention as a rapidly growing, solitary, subcutaneous or superficial soft tis sue mass that often causes alarm for the patient and the treating physician. NF arises in the upper extremities of adults. The volar surface of the forearm, followed by the trunk, chest wall, and back are common sites ofoccurrence, but NF has been reported in many other locations.NF affects the soft tissues at a subcuticular or fascial level but may extend to the deeper skeletal muscle. NF can be divided into three subtypes based on their relationship with the fascia: subcutaneous, intramuscular, and fascial. Uncommon clinical and pathological variants of nodular fasciitis, such as intravascular, cranial, ossifying, and proliferative fasciitis, have been described. Due to the superficial location, NF is easily amenable to FNA. A history of trauma might precede NF, but its cause remains unclear. The clinical course is completely benign, but the high risk of misinterpreting NF as a malignant process owing to its rapid growth, high cellularity, and high mitotic activity is well-known. Histologic characteristics of NF are varied and include plump immature fibroblast-like spindle cells, chronic inflammatory cells, microvascular proliferation, extravasated red blood cells and mucoid matrix material. In addition to the cytological findings described above in this case, NF are known to have occasional large ganglion-like cells, background mucoid matrix, foamy cells, cells resembling reapir phenomenon in exfoliative cytopathology and fragments of atrophic or degenerate skeletal muscle tissue. NF are easily and often misdiagnosed even by experienced pathologists both on FNA and histopathology with a reported error rate of as high as 50%. From a cytopathologic perspective, the main differential diagnosis of NF includes DFSP , low- grade myxofibrosarcoma, and synovial sarcoma. NF tends to have a characteristic superficial location with a distinct well-circumscribed nodular appearance. The cells in NF have nuclei that are not hyperchromatic, the lesion does not extend to the skin, mitoses are rare and when present are not atypical and the amount of collagenized stroma is much smaller than is typically seen in fibrosarcomas. NF bears a close resemblance to organizing granulation tissue, and myofibroblastic proliferation may be initiated by a local injury or local inflammatory process, which supports a reactive proliferation triggered by trauma. As most cases are surgically excised the natural history of NF is not well understood. However, local recurrence is rare and those managed conservatively usually resolve spontaneously. References: Saad RS, Takei H, Lipscomb J, Ruiz B: Nodular fasciitis of parotid region: a pitfall in the diagnosis of pleomorphic adenomas on fine-needle aspiration cytology. Diagn Cytopathol 2005, 33:191-194. Plaza JA, Mayerson J, Wakely PE, Jr.: Nodular fasciitis of the hand: a potential diagnostic pitfall in fine-needle aspiration cytopathology. Am J Clin Pathol 2005, 123:388-393 Kong CS, Cha I: Nodular fasciitis: diagnosis by fine needle aspiration biopsy. Acta Cytol 2004, 48:473-477 Wong NL: Fine needle aspiration cytology of pseudosarcomatous reactive proliferative lesions of soft tissue. Acta Cytol 2002, 46:1049-1055 Matusik J, Wiberg A, Sloboda J, Andersson O: Fine needle aspiration in nodular fasciitis of the face. Cytopathology 2002, 13:128-132 Maly B, Maly A: Nodular fasciitis of the breast: report of a case initially diagnosed by fine needle aspiration cytology. Acta Cytol 2001, 45:794-796 Dodd LG, Martinez S: Fine-needle aspiration cytology of pseudosarcomatous lesions of soft tissue. Diagn Cytopathol 2001, 24:28-35 Aydin O, Oztuna V, Polat A: Three cases of nodular fasciitis: primary diagnoses by fine needle aspiration cytology. Cytopathology 2001, 12:346-347 Kilpatrick SE, Ward WG, Chauvenet AR, Pettenati MJ: The role of fine-needle aspiration biopsy in the initial diagnosis of pediatric bone and soft tissue tumors: an institutional experience. Mod Pathol 1998, 11:923-928 Meffert JJ, Kennard CD, Davis TL, Quinn BD: Intradermal nodular fasciitis presenting as an eyelid mass. Int J Dermatol 1996, 35:548-552 Powers CN, Berardo MD, Frable WJ: Fine-needle aspiration biopsy: pitfalls in the diagnosis of spindle-cell lesions. Diagn Cytopathol 1994, 10:232-240; discussion 241 Stanley MW, Skoog L, Tani EM, Horwitz CA: Nodular fasciitis: spontaneous resolution following diagnosis by fine-needle aspiration. Diagn Cytopathol 1993, 9:322-324 Raab SS, Silverman JF, McLeod DL, Benning TL, Geisinger KR: Fine needle aspiration biopsy of fibromatoses. Acta Cytol 1993, 37:323-328 Kaw YT, Cuesta RA: Nodular fasciitis of the orbit diagnosed by fine needle aspiration cytology. A case report. Acta Cytol 1993, 37:957-960 Layfield LJ, Anders KH, Glasgow BJ, Mirra JM: Fine-needle aspiration of primary soft-tissue lesions. Arch Pathol Lab Med 1986, 110:420-424 Azua J, Arraiza A, Delgado B, Romeo C: Nodular fasciitis initially diagnosed by aspiration cytology. Acta Cytol 1985, 29:562-565