He testified during last year's high-profile trial against Dr. Kermit B. Gosnell, his former boss and founder of the now-closed Women's Medical Society clinic in West Philadelphia.
Due in part to Massof's testimony, Gosnell was convicted and received three life sentences without parole.
During yesterday's hearing, one of Massof's attorneys, Jeffrey Lindy, told Lerner that Gosnell had bad-mouthed Massof as a "snitch" to other inmates at the city's Curran-Fromhold Correctional Facility. This led to Massof receiving threats and having to be moved into federal custody, Lindy said.
Massof and Gosnell were among 10 clinic employees arrested in January 2011 in what came to be known as the "house of horrors" case.
Of the 10 defendants, eight pleaded guilty before trial. Three remain to be sentenced.
Massof was a 1998 graduate of St. George's University Medical School in Grenada, an island nation in the Caribbean. When hired by Gosnell in 2003, Massof had been working as a cook and bartender and had not passed the required tests to practice medicine in the U.S.
Still, he testified, he was told to act as a doctor, including prescribing drugs, treating patients and presiding at abortions.
He cut the spinal cords of late-term infants born alive as Gosnell had taught him, Massof testified.
Although prosecutors Edward Cameron and Joanne Pescatore asked for a sentence of 10 to 20 years, Lerner noted Massof's "spotless" prior criminal record and the fact that he fully cooperated with authorities in Gosnell's case as reasons for a lesser sentence.
Lerner, however, chastised Massof for using his education and training to knowingly participate in taking advantage of poor and uneducated women.
"As evil as Dr. Gosnell is, as charismatic as he may have been, he could not do this alone, and mainly he could not do it without assistance from someone like you," Lerner told the weepy defendant.
He also ordered that Massof is not to be housed with Gosnell, and that after being released from prison he must serve three years of probation, which is to run concurrently with a four-year probation term he is now serving for a federal conviction related to the clinic.
Because Massof has been jailed for three years already, he could be eligible for parole in three years.
On Twitter: @MensahDean