Some shocking new details are being reported about Joan Rivers' tragic passing, and if they're true, we have a feeling it's only a matter of time before there's a wrongful death lawsuit...

Rivers, 81, went to Yorkville Endoscopy in New York City on August 28 for a "diagnostic procedure [to] see why her voice had gotten raspy," according to the New York Daily News.

Apparently the doctor performing the endoscopy found "something" on Rivers' vocal cords, but then another doctor, whom Rivers reportedly brought with her (and didn't work for the clinic), "asked if he could use their instruments" to perform an unplanned throat biopsy.

The paper reports that Rivers had agreed to the endoscopy, but NOT the biopsy, and that it was "a huge no-no" for Yorkville Endoscopy to allow another doctor to perform the operation.

During the biopsy, Rivers reportedly suffered a vocal cord contraction laryngospasm, which stopped her breathing. Sources told the NYDN that if the biopsy had been done in a hospital, the legendary TV personality "might have been okay."

Rivers passed away on Thursday, September 4, approximately a week after initially being rushed to the ER following the procedure. Neither Rivers' daughter Melissa nor representatives from Yorkville Endoscopy have commented on the report...