HGTV's Loren Ruch Died From Pneumonia, Was Cancer-Free, Family Says

Loren Ruch, head of content for HGTV and cohost of "HGTV House Party," died Thursday at Mount Sinai in NYC ... and his family is clarifying exactly what happened to the beloved media personality.

Dolly Norris, Loren’s mother, tells TMZ … the HGTV fixture was diagnosed with acute myeloid leukemia about a year ago, and treatment for the cancer left him with a weakened immune system. He was hospitalized a few months back for a bowel blockage -- and he then caught pneumonia, which ultimately was his cause of death. Dolly tells us he was cancer-free.

Loren's passing is even more devastating for the family, as just a few weeks ago he seemed to be on the road to recovery … but, Dolly says, he took a turn for the worse and his health declined quickly -- including a lung collapsing.

In a memo leaked to the press ... Channing Dungey, chair of Warner Bros. Television Group, called Loren "the rare leader who lifted everyone around him."

Loren's mother tells us he was also the most humble of people ... and he lit up every room he was in -- and that's why Dolly has been inundated with texts and calls about his passing.

We hear the family is planning a small family service in NYC … and then a large celebration of life in L.A., per Loren’s wishes.

He is survived by Dolly; his husband, David Salas; his brother, Geoffrey, his father, Larry; and his stepfather, Will Waterman.

Loren was 55.