Giant cell angioblastoma in an adult: a unique presentation

Abstract

Giant cell angioblastoma is a very rare, locally destructive vascular tumor of intermediate malignancy without metastatic potential. There are only a few cases reported in the literature exclusively in the soft tissue of children. For the first time, we report on an adult patient with a giant cell angioblastoma in the popliteal fossa. The therapy included tumor resection with favorable clinical, oncological and functional outcome. Due to its locally destructive nature, surgery remains the mainstay of treatment. Histologically, giant cell angioblastoma is comprised of nodular aggregates of histiocytoid cells arranged around bland angiomatous spaces. Because of insufficient available data in regard to the definition of the entity, diagnostic criteria and its biological potential, it is not included in the new World Health Organization classification of tumors of soft tissue and bone. The differential diagnosis includes plexiform fibrohistiocytic tumor, myofibroma and giant cell fibroblastoma.

Keywords: angioblastoma; giant cell; intermediate malignancy; soft-tissue tumor; vascular tumor.

Figure 1.

T1-weighted magnetic resonance imaging of the right knee after administration of gadolinium.

Figure 2.

A) Small and middle sized arteries (arrow) with concentric proliferation of SMA positive spindle cells (inset; original magnification 200x) in the outer layers are seen accompanied by myxoid and collagenous connective tissue in the background (hematoxilin and eosin staining; original magnification 50x). B) Several small, whorly nodules (asterisks) consiting of histiocytoid bland cells and containing (arrow) some multinucleated giant cells of osteoclastic type (CD68 positive as seen in the upper inset; original magnification 200x) are seen in the center of the lesion (hematoxilin and eosin staining; original magnification 100x). These cells show partial nuclear expression of MITF (lower inset; original magnification 200x)

Figure 3.

A) There are numerous thick-walled blood vessels (asterisks) with an outer concentric proliferation of bland spindle cells. Between these vessels, there is a diffuse spindle cell proliferation with a loosely myxoid or collagenous matrix (hematoxilin and eosin staining; original magnification 25x). B) Focally there are striking nodular aggregates (asterisks) of palely eosinophlic histiocytoid cells admixed with occasional osteoclastic giant cells (arrow) (hematoxilin and eosin staining; original magnification 100x).