Morphological and immunohistochemical observations on Leiomyoma of the ventral ligament of the oviduct of the Hen

Leiomyomas of the ventral ligament (LVLs) of the oviduct from 2-year-old spent layers were examined. These tumours can be present either as single large masses or as multiple smaller nodules. The most common site of origin of the tumours was the centre of the free margin of the ventral ligament, but some small tumours were observed at the insertion of this ligament into the magnum of the oviduct. Most samples were highly vascular and some blood vessels within the tumours had vacuolation of the smooth muscle cells. These findings suggest that the proliferative processes leading to LVLs may include transformation of the blood vessels of the ventral ligament. Immunohistochemically, the tumour cells expressed vimentin, α-smooth muscle actin, desmin and heavy-caldesmon. These avian leiomyomas have been proposed as a model for similar tumours in other species.