A Las Vegas television anchor says she has a rare form of cancer caused by a pregnancy complication.

Michelle Velez revealed on social media she was diagnosed with a molar pregnancy, which is result of a genetic error during the fertilization process that leads to a growth of abnormal tissue within the uterus. At her first ultrasound, she said doctors discovered an empty sac.

“Instead of miscarrying, the pregnancy continued to grow and produced invasive tissue,” Velez wrote on Facebook. “In some very rare cases, that tissue can turn into cancer and spread to other organs in the body. That is what happened to me. No good reason… just unfortunate dumb luck.”

Velez developed what is called gestational trophoblastic neoplasia (GTN), a rare condition that occurs when tumors develop in cells that would normally form the placenta during pregnancy or after. It affects about 1 of every 1,000 pregnancies.

Dr. Hye Sook Chon, a gynecological oncologist at Moffitt Cancer Center, says 15% to20% of women who experience a complete molar pregnancy, or mole, develop GTN. Only 1% to 5% of women who have a partial mole develop GTN.

“Almost all patients with GTN following a partial mole have invasive disease, making metastatic disease rare,” said Chon. “In 11 studies, including more than 7,500 patients with a partial mole, only 76 (1%) developed persistent tumor, and only nine (0.1%) had metastases.”

Although it is rare and aggressive, GTN is highly curable when it is correctly diagnosed and treated. Chon sat on the National Comprehensive Cancer Network review panel that released national guidelines last year on how to best treat the disease.  

“Data from the National Cancer Database demonstrate that most American women with GTN receive initial treatment at facilities that treat an average of less than one case per year, with survival rates lower than reported from specialized disease centers,” said Chon. “Therefore, these guidelines have real time impact on patient care to provide step by step approaches based on clinical conditions.”

Velez is currently undergoing chemotherapy to treat the cancer that has spread to her lungs, spleen and liver. She says she is optimistic she will make a full recovery. “I know everyone is worried about me and scared,” she said. “But I feel confident I am going to be okay.”