Bruce Jenner -- RADIO SILENT With Family Over 'Changes'

Bruce Jenner is going through some radical physical changes that could be fundamentally altering who he is ... yet he is telling his family NOTHING.

TMZ broke the story ... Bruce went to a Beverly Hills plastic surgeon and scheduled surgery for a laryngeal shave -- which smooths out the Adam's Apple. He told TMZ, "I just never liked my trachea. "He also wanted a smaller nose. Bruce cancelled with the Bev Hills doc and subsequently got the procedure somewhere else.

Bruce has gone through other changes as well, including growing out his hair and nails in a pronounced way. And he seems to be growing breasts.

Under the category -- the 800 pound elephant in the room -- Bruce is saying nothing to his family about the changes ... some of which are markers of gender reassignment.

Bruce told TMZ he's not becoming a woman, which means he's telling us more than he's telling his brood. We're told Kim is completely in the dark -- he says nothing to her. And she's not alone.

A well-placed source on "Keeping Up with the Kardashians" tells TMZ .... no one on the show discusses the changes in Bruce ... and there are no plans to address them on the show.