A doctor who accidentally removed a patient's ovary, instead of her appendix, has been allowed to carry on practising.
Maria De Jesus, 32, died after the botched surgery at Queen's Hospital in Romford three years ago.
A medical watchdog has decided that junior surgeon Yah-ya Al-Abed can carry on working.
Baljit Ubhey, Chief Crown Prosecutor in London, described the attack as "extremely brutal", adding:
"The use of acid as a weapon is cruel and horrifying. It can have a devastating effect on victims and can cause long-term pain and disfigurement as well as emotional and psychological harm."
Baljit Ubhey added: "Mary Konye and the victim used to be friends and they had discussed the high-profile case of Katie Piper, who was the victim of an acid attack in 2008, and how Naomi had been particularly moved and upset by her story.
"Konye exploited this fear to cause maximum harm and her defence of suggesting that the victim would have thrown acid on herself was contemptible.
"Konye has now been brought to justice and must face the full consequences of her appalling actions."
Detective Chief Inspector Dave Whellams said it had been a "serious, horrible offence which required a degree of planning and calculation":
Mary Konye has had to purchase, at some point, some sulphuric acid. She has prepared for this over a number of months, even years, all resulting from a trivial, insignificant argument that everybody has in their everyday lives.
But Mary Konye has taken this so far that she has planned this, disguised herself and followed Naomi on that night of December 29 2012.
The result today will give Naomi only some comfort but she is never going to be away from the fact that she is scarred, every time she looks in the mirror she is going to be reminded of the fact but it will enable her to start to get some closure.
She is a very brave woman and one I have great sympathy for.
Judge, David Radford warned Mary Konye that she will face jail when he sentences her on March 7:
I should make clear that, in my judgment, this is a case that will, in all likelihood, need a substantial custodial sentence. It is inevitable, but it won't be dealt with until I have received those reports.
Victim, Naomi Oni burst into tears as she left the courtroom and was hugged by family and friends.
Mary Konye remained calm and stony-faced as the guilty verdict was announced to a packed court room. Naomi Oni's mother jumped from her set and appeared jubilant at the verdict.
Judge, David Radford adjourned sentence until March 7 while psychological reports are prepared and said:
In ordering these reports my judgement is that in all likelihood the case well lead to a substantial custodial sentence.'But it will not be decided until I have had these reports - I do not want Konye to misunderstand the reasons.
A young woman has been found guilty of throwing acid in the face of a friend while disguised in a Muslim veil. 21-year-old Mary Konye attacked Naomi Oni, an assistant at a Victoria's Secret lingerie shop, in December because she once called her ugly.
During her trial, the jury at London's Snaresbrook Crown Court heard that, following the attack, Konye pretended to give Ms Oni a shoulder to cry on.
Police in Havering have appealed for the public's help in finding a missing man.
Cornelius Sullivan, 49, was last seen on Monday 9 December in the Romford area in Havering.
He is described as white, of slim build and approximately 5ft 10ins tall. He has short greying hair and speaks with an Irish accent.
Anyone who has seen Cornelius or knows of his whereabouts, please contact Romford police via 101. Alternatively contact Missing People on 116 000.
A midwife who left a four-day-old baby face down in a stationery cupboard in a hospital in Essex has been given a three year caution. 35-year-old Yvonne Musonda-Malata was caring for the newborn girl at Queen's Hospital in Romford while her sick mother slept.
A tribunal heard she "failed to provide appropriate clinical care" to the baby while working on a night shift.
Yvonne Musonda-Malata will appear the hearing again tomorrow, when the Nursing and Midwifery Council will have to decide whether she will be punished. She had to rush from the hearing room last week after breaking down in tears, saying:
My life has nosedived into what I can only describe as a nightmare. I kept hoping it would be over, but it went from bad to worse.