Soft Tissue Giant Cell Tumour of Low Malignant Potential: A Rare Tumour at a Rare Site

Abstract

“Soft tissue giant cell tumour of low malignant potential” is considered as the soft tissue counterpart of osteoclastoma of the bone. It is a primary soft tissue tumour which is classified under the category of fibrohistiocytic tumours of intermediate malignancy.Seventy percent of the tumours involve the extremities and only about seven percent of them arise in head and neck region. They are composed of nodules of histiocytes in a vascular stroma, with multinucleated osteoclast-like giant cells positive for vimentin, smooth muscle actin (SMA), CD68 and Tarterate Resistant Acid Phosphatase (TRAP). We are presenting a case of a 75-year-old man who had a nodule on the ala of the nose. Histopathology showed a histiocytic lesion. Benign fibrous histiocytoma, plexiform fibrohistiocytic tumour, solitary reticulohistiocytoma and histioid leprosy were ruled out by using special stains and immunostains. Expression of smooth muscle actin and CD68 confirmed the diagnosis of a soft tissue giant cell tumour with a low malignant potential.

Keywords

• giant cell tumour
• malignant potential
• soft tissue