Isolated sporadic uterine lymphangioleiomyoma with unusual clinical and pathological features

We report a unique uterine neoplasm, favoured to represent an isolated extrapulmonary lymphangioleiomyoma with unusual pathological features, in a postmenopausal woman without tuberous sclerosis complex. The large neoplasm consisted of smooth muscle fascicles and cystic spaces lined by lymphatic cells, which were negative for the melanocytic staining that is characteristically positive in lymphangioleiomyomatosis (LAM). There are fewer than 30 cases of uterine LAM reported, none of which have demonstrated this morphology or these immunohistochemical findings. The origin of LAM cells in the more typical pulmonary LAM remains unclear; the unusual features in this case may represent a distinct pathological entity or a rare variant of typical extrapulmonary LAM, and may contribute to determining the cellular origin of these rare tumours. Conversely, this may represent a case of 'prepulmonary' LAM, providing supporting evidence for a possible gynaecological origin of these tumours in the broader affected (almost exclusively female) population.