When Good Morning America co-anchor Robin Roberts revealed through tears on national television last month that she has myelodysplastic syndrome, millions of viewers likely were hearing of the blood disorder for the first time.

Just two weeks later, when writer and filmmaker Nora Ephron died of acute leukemia, most media reports did not explain that myelodysplastic syndrome predisposed the blood cancer that ended her life.

It’s no wonder that information about myelodysplastic syndromes, a collection of bone marrow blood disorders also called MDS, is not in the mainstream. Medical experts are still trying to figure it out.

Is MDS a blood cancer or not?

It’s complicated.

“The problem is that MDS represents a heterogenious [diverse] set of diseases. The syndrome is not the disease . It’s a variety of bone marrow mutations,” said Dr. Steven Fein, a hemotologist/oncologist at Baptist Health South Florida.

Simply, the bone marrow does not function properly, so patients develop life-threatening low blood cell and low platelet counts, said Dr. Stephen Nimer, director of the University of Miami’s Sylvester Comprehensive Cancer Center and president of the MDS Foundation. Symptoms can include fatigue, shortness of breath, bruising and bleeding.

MDS eventually obliterates bone marrow, which is the body’s stem cell blood production source, ground zero for the immune system and necessary to sustain life. Patients are rarely cured without a blood stem cell transplant or direct bone marrow transplant — as can happen for blood cancers like lymphoma, leukemia and myeloma.

“It wipes out the MDS and gives patients a new capability to create normal blood cells,” Nimer said.

Standard medications include the chemotherapy drugs 5-azacytidine, decitabine and lenalidomide.

MDS was called pre-leukemia until the 1970s when the term was dropped because only about 30 percent of MDS patients actually develop leukemia.

“Sometimes cancers are successfully treated and people survive, but there is that small group who can get leukemia or MDS from the treatment,” Nimer said.

Up to 2 percent of people with MDS are former cancer patients.

Roberts, during her broadcast revelation, said her MDS is likely a side effect of the chemotherapy she endured for breast cancer five years ago.

“Sometimes treatment can lead to other serious medical issues and that’s what I am facing,” Roberts told viewers. “It’s about focusing on the fight and not the fright.”

About 60,000 bone marrow or stem cell transplants are performed annually in the United States?, said Dr. Lyle Feinstein, director of the blood and marrow transplant program for Memorial Cancer Institute at Memorial Hospital West in Broward County.

Feinstein believes MDS is too much like cancer to be considered otherwise.

“MDS is a cancer — but not leukemia, yet. It is a bone marrow disorder where the blood stem cells become zero count and ultimately the disease can transform into cancer. It is a fallacy that it is not cancer,” Feinstein said.

Keiren Joyce, 66, of Hollywood, recently underwent a stem cell transplant using his own blood taken before a weeklong battery of chemotherapy for lymphoma. Joyce allowed The Miami Herald to document the 60-minute procedure.