A mother was killed at her hospital appointment by a doctor who botched a routine procedure, a court has heard.
Dr Isyaka Mamman, 85, was responsible for a series of critical incidents before the fatal appointment, Manchester Crown Court heard.
Mamman, who admitted gross negligence manslaughter, had already been sacked by medical watchdogs for lying about his age but was re-employed by the Royal Oldham Hospital.
He is due to be sentenced on Tuesday.
Mother-of-three Shahida Parveen, 48, had gone to hospital with her husband for investigations into possible myeloproliferative disorder on 3 September 2018 and a bone marrow biopsy had been advised, Andrew Thomas QC, prosecuting, told the hearing.
Normally, bone marrow samples are taken from the hip bone but Mamman, of Cumberland Drive, Royton, Oldham, failed to obtain a sample at the first attempt, he said.
Instead, he attempted a rare and "highly dangerous" procedure of getting a sample from Ms Parveen's sternum - despite objections from the patient and her husband, the court heard.
Mamman, using the wrong biopsy needle, missed the bone and pierced her pericardium, the sac containing the heart, causing massive internal bleeding.
Ms Parveen lost consciousness as soon as the needle was inserted. She died later that day.
Mamman qualified as a doctor in Nigeria in 1965 and had worked in the UK since 1991. From 2004 until the time of the fatal incident he was employed by the Pennine Acute Hospitals NHS Trust.
But his true age is a matter of "controversy", the court heard, as his birthplace in rural Nigeria had no system of birth registration.
He initially told the NHS he was born in 1941 and later he claimed he was born in 1947, suggesting he started his degree course at 10.
In 2004 he was found guilty of serious professional misconduct by the General Medical Council and suspended for a year for lying about his age.
The trust sacked him but then re-employed him in 2006, after he had been restored to the register by the GMC, who accepted his year of birth as 1943.
Mamman had left his previous employment with the Medway Trust because of "poor performance", and in 2015 a formal complaint was made to the Oldham hospital when a patient complained he used "excessive force" during a bone marrow biopsy.
The same year there was another clinical incident involving a bone marrow biopsy and a needle being inserted in the wrong place.
The patient survived but has been left permanently disabled.