Giant cell angioblastoma: three additional occurrences of a distinct pathologic entity.

Giant cell angioblastoma was described previously in a single case report as a congenital soft-tissue tumor with a unique morphology. In the current report, we describe three cases of giant cell angioblastoma found in three infants; one case was congenital and located in the hand, one appeared neonatally in the palate, and one on the scalp of an infant. Clinical findings and results of light microscopy, immunohistochemistry, and electron microscopy were evaluated. All tumors were ulcerated; the hand and palate tumors also infiltrated soft tissue and bone. They exhibited a solid, nodular, and plexiform proliferation of oval-to-spindle cells with a frequent striking, concentric aggregation around small vascular channels. These cells had characteristics of undifferentiated mesenchymal cells, fibroblasts, myofibroblasts, and pericytes. Co-mingled with these cells were large mononuclear and multinucleate giant cells with histiocytic features. The palatal giant cell angioblastoma, excised with positive margins, was managed with interferon-alpha and showed no progression after nearly 5 years. The hand tumor diminished in size after management with interferon-alpha, was subtotally excised, and did not progress after 27 months. Follow-up data are unavailable for the patient with the scalp lesion. Our findings validate the classification of giant cell angioblastoma as a distinct and rare entity that is locally infiltrative but slow growing. The morphology and diverse cellular differentiation are consistent with an unusual form of neoplastic angiogenesis.