Abstract
Malignant transformation of endometriotic cyst occurs in approximately 0.7% cases. Although mural nodules are considered the most valuable imaging finding in diagnosis of ovarian cancers associated with endometriotic cyst, they are difficult to distinguish from clots with endometriotic cyst. Therefore, we often perform laparotomy for benign endometriotic cyst to rule out ovarian cancer. We selected six patients who underwent laparotomy for suspected ovarian cancer associated with endometriotic cyst, but who were confirmed not to have ovarian cancer pathologically. We retrospectively studied the clinical and imaging features of these six patients. We suspected malignant transformation of endometriotic cyst in patients with mural nodules on MRI or absence of shading on T2-weighted images as well as in older patients, however, mural nodules in the six patients were not enhanced or had unclear enhancements on T1-weighted contrast-enhanced images; all nodules showed benign contents such as fibrotic tissue, edematous stroma, and clots. Our study showed that mural nodules which are not clearly enhanced T1-weighted contrast-enhanced image appear to have low potential for malignancy. Therefore, in such cases, careful diagnosis using the dynamic subtraction study and minimally invasive surgery such as laparoscopy may be considerd.
