Inflammatory pseudotumor of the uterus.

The clinical and pathological features of two cases of inflammatory pseudotumor of the uterus are reported, a lesion previously undescribed in this site. In Case 1, a 6-year-old girl presented with abdominal pain, distension, and a suprapubic mass on physical examination. The lesion in Case 2 was an incidental finding in a 30-year-old woman at the time of hysterectomy. In both cases, solitary leiomyoma-like masses, measuring 12.5 and 4.5 cm in maximum diameter respectively, involved the myometrium. On histological examination the lesions were characterized by an admixture of spindle-shaped cells and a mixed inflammatory infiltrate rich in plasma cells. The spindle cells were positive for actin with immunoperoxidase staining, and in Case 1, exhibited the ultrastructural features of myofibroblasts. Both patients are alive with no evidence of disease at postoperative intervals of 5 and 4 1/2 years, respectively. The literature pertaining to other inflammatory and reactive tumor-like lesions within the female genital tract is reviewed.