Fibroblastic Rheumatism Versus Variant Disease of Multinucleate Cell Angiohistiocytoma

We report an unusual case of a 49-year-old woman who presented with persistent papulonodules over bilateral fingers and inframammary region in conjunction with features of connective tissue disease including symmetrical polyarthritis and Raynaud phenomenon. Skin biopsy showed an upper-to-mid dermal proliferation of bland spindled cells with thickened collagen bundles and occasional multinucleated giant cells. Dermal blood vessels were only marginally increased. On immunohistochemistry, both the spindled cells and multinucleated giant cells stained negatively for smooth muscle actin. Some of the spindled cells stained positively with CD68 and CD163, whereas the multinucleated giant cells stained negatively for both stains. Elastic fibers were absent on elastic Van Gieson. The clinical and histopathologic features raise a diagnostic dilemma between fibroblastic rheumatism and multinucleate cell angiohistiocytoma. The patient responded well to cyclosporine and methotrexate therapy, with gradual improvement of the finger nodules.