Hi, I Am 34 Years Old. Last Year Through A

Hi, I am 34 years old. Last year through a CT scan found to have a complex septated cyst with internal echoes. Since it was small that time my dr didn't do any treatment and followed up with ultrasound every 2 to 3 months. My last ultrasound revealed this is growing rapidly and my dr ordered a MRI. Is this anything to be concerned? MRI waiting is long. PS: I have a long history of severe endometriosis and I am also diagnosed with thyroid cancer last year and had thyrodectomy and radiation for the vascular invasion.