POSTTRAUMATIC SPINDLE-CELL NODULES - IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL-STUDY OF 2 SCROTAL LESIONS

We studied two cases of proliferative spindle cell lesions that develo ped in the scrotum secondary to trauma. The two patients, 22 and 67 ye ars of age, presented clinically with tumor masses and were treated wi th surgical excision. No recurrences were seen after 12 and 13 months, respectively, of follow-up. In both cases the tumor nodules were asso ciated with hematomas of the scrotal subcutaneous tissue, with disrupt ion of the tunica dartos. The lesions were composed of monomorphic, de nse, spindle cell proliferations that formed irregular nodules in the wall of the hematoma and disrupted the smooth-muscle bundles of the ar ea. On immunohistochemical and ultrastructural studies, the tumor cell s were consistent with myofibroblasts with pronounced smooth-muscle di fferentiation. Both cases had a striking histologic resemblance to the postoperative spindle cell nodules that occur in the genitourinary tr act secondarily to surgical trauma. The morphological features, prolif erating cell type, and benign clinical course are identical in both of these conditions, which appear to represent a stereotyped form of rea ctive change after injury and hemorrhage in the vicinity of smooth mus cle.