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

Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
The American journal of surgical pathology (Impact Factor: 4.59). 01/2012; 36(4):500-8. DOI: 10.1097/PAS.0b013e31823defbe
Source: PubMed

ABSTRACT Thirty-seven cases of a distinctive benign fibrovascular soft tissue tumor that may be mistaken for a low-grade sarcoma are described. There were 25 female and 12 male patients, ranging in age from 6 to 86 years (median, 49 y). The tumors presented most commonly as a slowly growing painless mass located in the soft tissues of the extremities, mainly the lower extremity, often in relationship to joints or fibrotendinous structures. Most lesions (29 cases) were well circumscribed, ranging in size from 1.2 to 12 cm (median, 3.5 cm). The microscopic appearance was remarkably consistent and was characterized by 2 components: a relatively uniform proliferation of bland, spindle-shaped cells with inconspicuous cytoplasm and ovoid-to-tapering nuclei set in a variably collagenous or myxoid stroma and a prominent vascular network composed of numerous small, branching, thin-walled blood vessels, often accompanied by medium-sized round or irregular and ectatic vessels. Mitoses (1-4/10 hpf) were occasionally observed (9 cases). Mild degenerative nuclear atypia was uncommon (5 cases). Tumor cells expressed epithelial membrane antigen at least focally in 16 of 36 cases (44%), CD34 and smooth muscle actin in 5 cases (14%), and desmin in 4 cases (11%); none expressed S100 protein. Five out of 6 cases analyzed cytogenetically showed a simple karyotype with a balanced t(5;8) chromosomal translocation. Treatment consisted of surgical resection: either simple excision (29 cases), wide excision (6 cases), or amputation (1 case). Follow-up information was available for 28 patients (range, 6 to 144 mo; mean, 51.9 mo). Most patients were alive with 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; only in 1 case was there an association with extensively positive surgical resection margins. One of these patients developed a second recurrence 2 months after the first one. None of the patients developed metastasis. The designation "angiofibroma of soft tissue" is proposed to reflect both the likely fibroblastic nature of the proliferating cells and the prominent vascularization of this benign soft tissue neoplasm.

  • Pathology International 06/2014; 64(6). DOI:10.1111/pin.12161 · 1.59 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Solitary fibrous tumor is a mesenchymal tumor of fibroblastic type, which can affect any region of the body. Recently, a recurrent gene fusion NAB2-STAT6 has been identified as molecular hallmark. The NAB2-STAT6 fusion leads to EGR1 activation and transcriptional deregulation of EGR1-dependent target genes and is a driving event in initiation of SFT. In this study, we report the clinicopathologic and RT-PCR findings and evaluated expression of STAT6 and EGR1 protein in a cohort of 28 SFTs.Methods28 patients with a median age of 54 years were included with SFTs originating at different sites, most occurring in the lung and pleura (9, 32%), 5 in soft tissues of the lower extremities (18%) and 5 in the head and neck (18%). For detection of the NAB2-STAT6 fusion gene, RT-PCR was performed using RNA extracted from formalin-fixed and paraffin-embedded tissues. Immunohistochemistry was performed on all cases with antibodies against STAT6 and EGR1.ResultsAll patients were treated by surgery, 3 with adjuvant chemo- or radiotherapy. Follow-up data of 18 patients could be obtained of which 2 patients died of metastatic disease 13 months and 52 years after first diagnosis. Sixteen patients have no evidence of disease with a median follow up of 29.5 months (range 7 ¿ 120 months). NAB2-STAT6 fusion transcripts were found in 19/28 cases (68%). The most common fusion was between NAB2 exon 4 and STAT6 exon 3 (11/19, 58%), mainly occurring in pleuropulmonary lesions. All cases showed strong nuclear expression of STAT6 (28/28, 100%) while EGR1 showed low-level variable nuclear expression in all samples, comparable with the EGR1 expression results of the control group.Conclusions The identification of the NAB2-STAT6 fusion in SFTs can provide important diagnostic information, especially in cases with aberrant morphology or when biopsy material is limited. STAT6 immunohistochemistry is another useful tool in diagnosing SFT. EGR1 immunohistochemistry indicates low-level protein expression in accordance with EGR1 activation due to distorted NAB2 activity.Virtual SlidesThe virtual slide(s) for this article can be found here:
    Diagnostic Pathology 11/2014; 9(1):224. DOI:10.1186/s13000-014-0224-6 · 2.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Angiofibromas are rare, benign, locally invasive vascular tumors, which represent 0.05-0.5% of all head and neck tumors. Most frequent site of occurrence is the posterior nasopharynx, called as nasopharyngeal angiofibromas (NA), when these arise outside the nasopharyngeal region they are termed as extranasopharyngeal angiofibromas (ENA). Only 65 cases of ENA have been reported, and the most common site has been reported to be maxilla followed by ethmoids. Other unusual sites of occurrence reported so far in literature are nasal cavity, nasal septum, larynx, sphenoid sinus, pterygomaxillary fissure, infratemporal fossa, cheek, oropharynx, retromolar area, middle turbinate, inferior turbinate, and tonsil. ENA arising from the superficial lobe of parotid gland has not been reported in the literature so far and this case is the first to be reported.
    Journal of Oral and Maxillofacial Pathology 05/2014; 18(2):295-8. DOI:10.4103/0973-029X.140798