Limbani Mzoma’s mutilated body was found in a pool of blood at around 11:30pm on Thursday.
The man, who is believed to be from Ghana, was stabbed repeatedly during the attack.
Mr Mzoma was found just hours after local police had been called to Dublin’s affluent housing estate Tudor Lawns in Foxrock to deal with a public disturbance.
According to sources his genitals were “removed from his body” along with his eyelids.
A source said: “The scene is in a house where a number of non-nationals have been living.
“There has been a lot of trouble at the property and police were called there on Thursday afternoon.
“They dealt with a public order incident and left.
“When they were called back at 11.30pm they discovered the man dead.
“The severed penis was found on top of the fireplace and they also chopped off his eyelids.”
Irish police arrested a woman in her 40’s following the incident.
She was in the house when police arrived and has been detained in Dun Laoghaire Garda Station for questioning.
Tudor Lawn residents were mortified at the death.
One elderly woman, who lives a few doors down from the crime scene, said there had been a lot of problems at the house.
She said: “I heard the commotion yesterday afternoon and then last night again.
“There was a lot of police and some ambulances there.
“There has been a lot of people coming and going from there and it has been a big worry.
“It is shocking, and tragic that someone has lost their life.
“I hope they have caught the person.”
Irish police released a statement yesterday and appealed for witnesses.
A spokesman said: “Police investigating the circumstances of the discovery of the body of a man in a house at Tudor Lawns, Foxrock have made an arrest.
“A woman has been arrested in relation to this investigation and is currently detained at Dun Laoghaire under Section 4 of the Criminal Justice Act, 1984.”