OAP wins six-figure payout after Birmingham hospital unnecessarily amputates leg
But medical negligence expert Tim Deeming said the incorrect diagnosis was not an isolated case.
He said in 1993 the hospital identified a problem with its histopathology department and a report published in 2001 said there had been a "a worrying increase in apparent errors."
A review ordered into all cases over the previous eight years found out of 1,996 cases, errors were found in 87.
Of these 54 cases (2.7%) were regarded as sufficiently serious to require a change in patient treatment.
Mr Deeming said: "This is not the usual story or an error by an inexperienced, junior medic, but of a group of clinical experts - three of them world-renowned in their particular fields.
"Independent experts have confirmed that if an open biopsy rather than a needle biopsy had been carried out on Mrs Nicholls' foot prior to surgery, this would have led to the correct diagnosis.
"Given that not all members of the medical team came to the same conclusion, the question remains why their findings weren't double checked before they carried out the amputation.
"If Mrs Nicholls' case had been an isolated incident, this would have been bad enough, but I am extremely concerned that the hospital appears to have learned nothing from the previous errors it identified back in 1993 and has not taken the necessary steps to protect patients from the risks of misdiagnosis."
The Royal Orthopaedic Hospital NHS Foundation Trust said it was "deeply sorry" about the outcome of Mrs Nicholls' treatment but it was in no way linked to the problems in 1993.
A spokeswoman said: "The Royal Orthopaedic Hospital is one of a small number of hospitals in Europe dealing with extremely rare and unusual bone and soft tissue tumours.
"This trust is recognised around the world as a leading centre of excellence.
"Our clinicians and their support teams are internationally recognised for their work in the diagnosis and treatment of such tumours.
"Some of the tumours we treat may occur only once in a generation and are extremely difficult to diagnose."
She said it was a "matter of regret" that Mrs Nicholls' case was one of these extremely rare conditions.
"We were advised the care provided by the trust was not negligent. Those advising Mrs Nicholls reached a difficult conclusion," the spokeswoman added.
She said claims for clinical negligence were handled by the NHS Litigation Authority on their behalf and it was decided to reach a settlement with Mrs Nicholls through a "positive dialogue" between her lawyers and the NHS LA.
She added: "There is no link between this case and the cases in 1993. A review took place as a result of the problems in 1993 and the trust established its own in-house laboratory - one of the largest in Europe.
"It undergoes annual inspection and has recently had its CPA accreditation renewed. All pathologists are fully up to date with their required continuing professional development and play an active part in teaching and research across the world.
"Our pathologists are nationally and internationally recognised in the field of bone and soft tissue tumours.
"Since 1993 the pathology laboratory has reported on approximately 35,000 specimens without any recurrence of the 1993 problems.
"We are confident that the service we provide to our patients is one of the best in the world."
