The federal government has acknowledged it was negligent in the death of an immigrant whose cancer went undiagnosed for nearly a year while he was in custody.

The government last week acknowledged medical negligence, an allegation contained in a lawsuit filed by the family of 36-year-old Francisco Castaneda.

"Was there medical negligence, and we're saying yes," U.S. attorney's spokesman Thom Mrozek said in Los Angeles on Wednesday.

The claim carries maximum damages of $250,000, he said.

Castaneda, an illegal immigrant from El Salvador, was placed in immigration custody after serving an eight-month state prison sentence on a 2005 conviction for possessing methamphetamine with intent to distribute.

While at the San Diego Correctional Facility, he notified immigration officials that he had a large, painful, growing lesion on his penis.

Despite recommendations from several doctors, the cancer was never biopsied and Castaneda received no treatment except for pain pills during his 11 months in detention, government records indicated.

A doctor at the Division of Immigration Health Services would not admit Castaneda to a hospital, saying her agency considered it "an elective outpatient procedure."

Castaneda was released last year, went to a hospital and was diagnosed with metastatic squamous cell carcinoma. He died in February at age 36.

He testified about his case before Congress last year.

A federal judge in March ruled that the alleged denial of medical treatment was "beyond cruel and unusual punishment," allowing Castaneda's family to go forward with the suit.