DISSECTING LEIOMYOMA OF THE UTERUS WITH EXTRAUTERINE EXTENSION

Aims: Familiarity with benign uterine smooth muscle tumours with unusu al growth patterns by gynaecologists and pathologists is essential in avoiding misdiagnosis and overtreatment. Case details: An enlarged ute rus in a 35-year-old woman contained numerous, ill-defined nodules wit h marked hydropic changes which showed an extrauterine extension, Hist ologically, although some nodules had an appearance of conventional le iomyoma, the predominant part of the lesion was characterized by ill-d efined spindle cell nodules with marked hydropic changes and irregular dissection of the myometrium. The cellularity was variable from area to area and there were neither nuclear atypia nor mitotic figures. No coagulative tumour necrosis was observed, The extrauterine components, which were in continuity with the intrauterine nodule, were histologi cally identical to the intrauterine nodules except for the complicatio n of endometriosis. Immunohistochemically, the tumour cells were posit ive for vimentin, desmin, alpha-smooth muscle actin and muscle actin ( HHF35). The tumour was DNA diploid by flow cytometry. The patient was well and without disease 6 months after hysterectomy. Conclusions: Thi s tumour illustrates that rare benign smooth muscle tumours can prolif erate in dissecting and extrauterine growth patterns, Endings that sho uld not be confused with malignant mesenchymal tumours.