Insurance refused to cover imaging to identify my spouse's squamous cell carcinoma on an ovary because initial bloodwork didn't come back positive for ovarian cancer (squamous cell required different bloodwork, at least at the time).

It took a doctor offering to misdiagnose it as a dermoid cyst to get the imaging and hysterectomy ordered and approved, and that still took 2 months. By the time it happened, the cancer had metastasized.

The imaging would've cost a few thousand dollars. The hysterectomy would've cost about $20k-40k. Chemo was unsuccessful, and she died 9 months and about $2 million in medical bills later.

Which insurance firm was this?

Fwiw, if one has a passport and some funds, one can travel abroad for cheaper surgery abroad. It won't guarantee an outcome, but it ought to be better than delaying it. Of course this in no way excuses the insurance firm.