Postoperative spindle cell nodule is a localized, non-neoplastic, reparative lesion composed of closely packed proliferating spindle cells and capillaries simulating a leiomyosarcoma. The lesion typically develops at the site of a recent surgical wound several weeks to months postoperatively. Local recurrence of postoperative spindle cell nodules has not been reported, even after incomplete resection. We cytogenetically analyzed two postoperative spindle cell nodules, one arising in the vulva and the other in the urinary bladder. Trisomy 7 was identified as the sole karyotypic abnormality in the lesion from the vulva, in which cell culturing and G-banding analysis were possible. The other case, from the urinary bladder, showed presence of trisomy 7 by interphase-FISH performed on nuclei extracted from paraffin-embedded tissue.