Postoperative spindle cell nodules (PSCN) resembling sarcomas: an atypical granulation tissue or atypical pyogenic granuloma with exuberant myofibroblastic component?

Three cases of PSCN that developed 6-8 weeks after operations to the lower genital tract in two women, and after tooth removal in a 9-year-old boy are described. The lesions averaged 2 cm. in diameter and simulated spindle cell sarcomas because of their high mitotic rate, and marked cellularity. On follow-up (2-6 years) all patients were found to be free of disease. Immunohistochemical testing of the spindle cells showed a strong positivity for vimentin, and muscle actin and a weak, focal and inconstant positivity for F. VIII R.A., and Ulex E. The was total negativity for desmin, smooth muscle actin, S 100 Protein and Cytokeratins. We believe that these lesions represent an atypical form of granulation tissue in which the exuberant myofibroblastic component obscure the vascular elements of the lesion.