[Uterine leiomyoma with massive lymphoid infiltration: case report].

Uterine leiomyoma with massive lymphoid infiltration is a rare and unusual pathological finding; only 20 cases have been reported in the literature. We report a case of this unusual lesion in a 35-year-old woman who underwent a myomectomy. On gross examination, the tumor was of white color and firm consistency. Histological sections showed interlacing bundles of spindle shaped cells of low density with moderate to severe lymphocytic infiltrate associated to lymphoid follicles and few plasma cells. Immunohistochemically, the diffusely infiltrating lymphoid cells were predominantly of T cell phenotype. The interspersed spindle shaped cells were positive with alpha smooth muscle actin, desmin and h-caldesmon. The cause of this unusual lesion is not clear, but the recognition of its distinct histological features is important to avoid possible confusion with differential diagnosis including malignant lymphoma, inflammatory pseudotumor and pyomyoma.