[58] Angiofibroma of Soft Tissue: Clinicopathologic Characterization of a Distinctive Benign Fibrovascular Neoplasm in a Series of 37 Cases

Adrian Marino-Enriquez, Christopher DM Fletcher. Brigham and Women's Hospital and Harvard Medical School, Boston, MA

Background: Fibroblastic tumors with prominent vascularization are rare, mainly limited to nasopharyngeal angiofibroma and cellular angiofibroma. We have become aware of a distinct benign soft tissue neoplasm with fibroblastic cytomorphology and a very noticeable vascular pattern which may be mistaken for a low grade sarcoma.
Design: Thirty-seven cases of a distinctive benign fibrovascular soft tissue tumor identified between 2000 and 2011 were retrieved from consultation files. Clinicopathologic and follow-up information was obtained from referring pathologists. H&Es were reviewed. IHC stains for CD34, EMA, SMA, desmin and S100 were performed.
Results: Patients were 25 women and 12 males, aged 6-86 years old (median 49 y). The tumors presented most commonly as a slowly growing painless mass in the soft tissues of the extremities, mainly the lower extremity, often in relationship to joints or fibrotendinous structures. Most lesions (29) were well circumscribed, 1.2-12 cm in size (median 3.5 cm). Microscopically, they were characterized by 2 components: a uniform proliferation of bland, spindle-shaped cells with inconspicuous cytoplasm and ovoid nuclei set in a variably myxoid stroma, and a prominent vascular network with numerous small branching thin-walled blood vessels, often accompanied by medium-sized round or ectatic vessels. Mitoses (1-4/10 hpf) were occasionally present (9 cases). Mild degenerative nuclear atypia was uncommon (5 cases). Tumor cells expressed EMA (usually focally) in 16/36 cases (44%), CD34 and SMA in 5 (14%) and desmin in 4 (11%); none expressed S100 protein. Cytogenetically, 5 out of 6 cases analyzed showed simple karyotypes with a balanced t(5;8) translocation. All patients were treated by surgical excision. Follow-up information was available for 28 patients (range 6-144 months; mean 51.9 months). Most patients showed no evidence of disease, regardless of the status of surgical resection margins. Four patients developed local recurrence 9, 13, 36 and 120 months after the primary tumor was removed; one developed a second recurrence 2 months later. None of the patients developed metastasis.
Conclusions: Angiofibroma of soft tissue is a previously unrecognized fibrovascular soft tissue tumor with distinctive morphology, arising most commonly in the extremities of middle aged adults. Preliminary data suggest that these tumors have a distinct and reproducible karyotype. The clinical course is benign, with rare local recurrences and no evident metastatic potential. Simple local excision seems to be adequate treatment.
Category: Bone & Soft Tissue

Tuesday, March 20, 2012 11:45 AM

Platform Session: Section G, Tuesday Morning


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