Lisa Monk, Mom Misdiagnosed with Cancer, Says Mistake Destroyed Kids' Innocence

Lisa Monk -- a woman misdiagnosed with cancer -- says she's not just angry for herself, but she's mad for her children ... who she says lost their innocence because of this ordeal.

We spoke with Lisa on "TMZ Live" ... who took us through her timeline of events -- beginning when she was improperly diagnosed with cancer, and her account is horrifying.

Monk says the hospital treating her ran its own in-house pathology report after she'd been diagnosed by a previous medical team. About a month after the test results came in, LM says a nurse practitioner finally looked at them ... and, looked at her in horror.

Lisa says the nurse rushed to get a doctor ... who explained she never actually had cancer -- before CONGRATULATING HER instead of apologizing.

Monk says the in-house report came in after the first round of chemotherapy ... but, because the hospital waited to read it, she also went through another round of chemo -- one she says left her looking and feeling super sick.

Monk says her relief turned to anger all in the same moment ... and, she says she's still super PO'd at the hospital -- WHICH IS STILL BILLING HER.

Lisa says the financial burden isn't as painful as the emotional trauma ... which she says stole the innocence of her children who had to grapple with the prospect of her mom dying.