The pathologist at the centre of the Alder Hey scandal told staff to retain organs of dead children without their parents' consent, a tribunal has heard.
Dr van Velzen failed to turn up for the hearing
Dutchman Professor Dick van Velzen failed to appear before the General Medical Council's (GMC) Fitness to Practise panel in Manchester on Monday.
He sent no legal representatives to enter a plea on his behalf.
The panel heard about 850 babies had become victims of the professor during his career at the Liverpool hospital.
If found guilty of professional misconduct, he could face a ban from practising again.
Prof van Velzen was appointed to the chair of foetal and infant pathology at the University of Liverpool in April 1988 and was responsible for leading research into cot deaths.
Opening the case for the GMC, Andrew Collender QC said the scandal had caused "considerable and understandable distress" to the parents of the children affected.
"At the heart of the charges against Prof van Velzen was his practice, while at Alder Hey, of removing and retaining the internal organs of infant patients following post mortem examinations.
"During the period from September 1988 to 1994 a very substantial store of foetal and infant organs built up at the Alder Hey Hospital.
"Investigations carried out after September 1999 found more than 2,000 pots containing organs from approximately 850 post-mortem examinations in store at the hospital."
Mr Collender went on to say how hospital techniques changed soon after Prof van Velzen was appointed.
"As soon as he arrived, although there was no significant increase in the samples sent for analysis, there was an increase in the number of special techniques asked to be performed on the samples."
The doctor changed the way post-mortem examinations were carried out and began removing many of the organs whole, rarely asking laboratory officers to process them into blocks and slides.
He said the techniques and processes used by the doctor led to a "build up of unprocessed organs in storage pots stored in a particular building in the hospital".
The tribunal continues.