Background

This rare soft tissue tumor was originally described as Giant Cell Angiofibroma of the Orbit, based upon its unique localization and distinctive histopathologic appearance. Since the initial report, additional sites have been identified.

PATHOGENESIS

CHARACTERIZATION

A giant cell angiofibroma involving 6q. Sonobe H, Iwata J, Komatsu T, Fukushima A, Hayashi N, Moriki T, Shimizu K, Ohtsuki Y. Department of Pathology, Kochi Medical School, Japan.

Cancer Genet Cytogenet 2000 Jan 1;116(1):47-9 Abstract quote Giant cell angiofibroma, a recently proposed new clinicopathological entity, arises exclusively in the orbit in adults and histologically exhibits features intermediate between those of giant cell fibroblastoma and solitary fibrous tumor. In a typical case of giant cell angiofibroma, abnormalities of chromosome 6 with a common pattern involving 6q13 were detected together with various other chromosomal aberrations. To our knowledge, this is the first reported case of giant cell angiofibroma demonstrating chromosomal abnormalities.

 

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
General
Giant cell angiofibroma. A distinctive orbital tumor in adults. Dei Tos AP, Seregard S, Calonje E, Chan JK, Fletcher CD. Department of Histopathology, St. Thomas's Hospital (U.M.D.S.), London, England.	Am J Surg Pathol 1995 Nov;19(11):1286-93 Abstract quote A series of seven cases of a previously unrecognized potentially recurrent tumor occurring in the orbit of adult patients is reported. This lesion shows histologic appearances intermediate between, but distinct from, solitary fibrous tumor and giant cell fibroblastoma of soft tissue. Morphologically it is characterised by a richly vascularized, patternless spindle-cell proliferation containing pseudovascular spaces. Multinucleate giant cells (often of floret type) and cells with large, rounded nuclei are present both in the cellular areas and also lining the pseudovascular spaces. The stroma is variably collagenized or sometimes myxoid. Immunohistochemically, the tumor cells exhibit positivity for vimentin and CD34. Follow-up in five cases (median duration 24 months) revealed local recurrence in one patient and persistent tumor in another. The clinical and morphologic features enable distinction of this lesion from both solitary fibrous tumor and giant cell fibroblastoma, and we suggest the designation "giant cell angiofibroma of the orbit".
VARIANTS
Extraorbital giant cell angiofibromas. Mikami Y, Shimizu M, Hirokawa M, Manabe T. Department of Pathology, Kawasaki Medical School, Kurashiki-city, Okayama, Japan.	Mod Pathol 1997 Nov;10(11):1082-7 Abstract quote We herein describe two unusual neoplasms showing histopathologic features consistent with those of giant cell angiofibroma, which was originally described as a neoplasm arising in the orbit in adults: one of them arose in the right submandibular region of a 48-year-old woman and the other in the right parascapular region of a 49-year-old woman. Macroscopically, although the latter was characterized by a lymphangioma-like cystic appearance, both tumors were well circumscribed and encapsulated. Microscopically, in both cases, pseudovascular spaces lined by a discontinuous row of multinucleated cells were seen against a background of spindle-shaped fibroblastic cell proliferation. In the second case, the tumor presented increased cellularity and plump and somewhat atypical nuclei of proliferating fibroblastic cells, compared with the tumor in the first case. Immunohistochemically, the mononuclear and multinucleated cells within these tumors were positive for vimentin and CD 34 but negative for any other antigens, including Factor VIII-related antigen, desmin, alpha smooth muscle actin, myoglobin, S-100 protein, LeuM1, lysozyme, alpha-1-antitrypsin, and cytokeratins (AE1/AE3 and CAM5.2). The features in these cases indicate that giant cell angiofibroma can arise in an extraorbital site in middle-aged patients and presents some histopathologic diversity.
A cutaneous case of giant cell angiofibroma occurring with dermatofibrosarcoma protuberans and showing bimodal CD34+ fibroblastic and FXIIIa+ histiocytic immunophenotype. Silverman JS, Tamsen A. Department of Pathology and Laboratory Medicine, Southampton Hospital, New York	J Cutan Pathol 1998 May;25(5):265-70 Abstract quote Dei Tos and colleagues in 1995 reported a series of seven distinctive orbital tumors in adults which they named giant cell angiofibroma (GCA). The morphologic features are intermediate between giant cell fibroblastoma and solitary fibrous tumor with a richly vascularized, patternless spindle cell proliferation forming a collagenous or myxoid stroma with pseudovascular angiectoid spaces. The spindled tumor cells have large, rounded nuclei, sometimes with complex folded shape and pseudoinclusions. There also are multi- or mononuclear giant cells, and these tumor cells partly line so-called angiectoid spaces. Cells express human progenitor cell antigen CD34 and vimentin. One case in the buccinator fascia was also noted by the authors, but similar cutaneous lesions are thus far unknown. We report our experience with a polypoid tumor that ocurred on the thigh of a 49-year-old woman that conforms to the description of GCA. The tumor has variegated vessels admixed with patternless spindle and giant cell stroma with angiectoid spaces as well as areas of dermatofibrosarcoma protuberans (DFSP). Most tumor cells express vimentin and CD34, including giant and spindle cells lining angiectoid spaces. Focally up to 40% of the lesional cells express coagulation factor XIIIa with histiocytoid to highly dendritic cytosomes. The DFSP component is composed of admixed CD34+ and FXIIIa+ dendritic cells arranged in a storiform pattern. Tumor cells are negative for actin, desmin, S-100, and cytokeratin. The Ki67 proliferation index is 1% in GCA areas and 3% in DFSP areas; Ki 67 stains mainly fibroblasts. We conclude that this cutaneous GCA is a fibrohistiocytic tumor closely related to and representing a more organoid angioformative analog of GCF, with both being related histogenetically also to DFSP. These lesions represent part of a greater spectrum of fibrovascular tissue patterns, all probably derived from proliferations of interactive microvascular CD34+ fibroblasts and FXIIIa+ histiocytes.
Orbital and Extraorbital Giant Cell Angiofibroma: A Giant Cell-Rich Variant of Solitary Fibrous Tumor? Clinicopathologic and Immunohistochemical Analysis of a Series in Favor of a Unifying Concept Louis Guillou, M.D.; Sandra Gebhard, M.D.; Jean-Michel Coindre, M.D. From the University Institute of Pathology, Lausanne, Switzerland (L.G., S.G.), and Bergonié Institute and University of Bordeaux II, Bordeaux, France (J.-M.C.).	Am J Surg Pathol 2000;24:971-979 Abstract quote The clinicopathologic and immunohistochemical features of one orbital and nine extraorbital soft tissue lesions, the morphology of which overlaps with giant cell angiofibroma and solitary fibrous tumor, are presented. There were 3 male and 7 female patients. Age at diagnosis ranged from 18 to 81 years (median: 45 yrs). Development of a mass was the main presenting symptom. For two patients, the lesion had been evident for several years before excision. Extraorbital tumors were located in the head and neck area (3), back (3), retroperitoneum (1), hip (1), and vulva (1). Tumor size ranged from 1.3 cm to 11 cm (median: 4.5 cm). The lesions presented grossly as well-demarcated, unencapsulated soft tissue masses. Histologically, they were characterized by the presence of alternating cellular and sclerosing areas, keloidal collagen deposition, round-to staghorn-shaped, thick-walled vessels and multinucleated giant stromal cells often lining pseudovascular spaces. Cellular areas were composed of non-atypical spindle to round cells set in a variably collagenous background. Mitotic activity ranged from 1 to 3 mitoses/10 high-power fields. Immunohistochemical studies showed positive staining of the spindle/round cells and multinucleated stromal cells invariably for epithelial membrane antigen, and keratin. Treatment consisted of simple tumorectomy in eight patients and wide excision in two. Follow-up information for eight patients (range: 7–32 mos; median: 14 mos), including four with microscopically positive surgical margins, showed no recurrence. These lesions share the clinical, pathologic, and immunohistochemical features of giant cell angiofibroma and solitary fibrous tumor, supporting the view that these tumors are closely related. In addition, it shows that giant cell angiofibroma occurs equally in both sexes and has a wider distribution than initially thought, developing even more often in extraorbital locations than in the orbit.

 

HISTOLOGICAL TYPES

CHARACTERIZATION

General

Intimate admixture of well-formed, thick-walled, often branching vessels of varying size with an intervening proliferation of spindle to round cells Some homogeneously cellular and richly vascularized while others showed alternating hypercellular and hypocellular/sclerotic areas, a pronounced collagenous background, as well as a ``staghorn'' pericytomatous vascular pattern Occasional amianthoid fibers

 

SPECIAL STAINS/IMMUNOPEROXIDASE/ OTHER	CHARACTERIZATION
Special stains
Immunoperoxidase	Positive for vimentin, CD34, CD99, and mostly for bcl-2 Negative for muscle specific actin, desmin, CD31, CD117 (c-kit), and inhibin. Occasionally, focal reactivity was observed for smooth muscle actin, S-100 protein,

 

PROGNOSIS AND TREATMENT	CHARACTERIZATION
Treatment	Simple to wide excision

Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

Soft Tissue Tumors

Last Updated 8/15/2001

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