The specimen shows an ovoid tumour arising in an ovary. The outer surface is smooth; the cut
surface shows a whorled appearance; the lesion is partly white in colour with yellowish areas.
There is a cyst at one pole.
This woman presented at the age of 60 with lower back pain and central abdominal pain,
frequency and nocturia. On examination a nodular mass was found in the pelvis and was
subsequently removed. These tumours, which are not common, are thought to arise from the
ovarian stromal externa and interna along the margins of the developing follicles. The yellowish
areas are an integral part of the tumour and are due to the accumulation of lipid in the tumour cells.