A team of Mexican Social Security Institute, or IMSS, doctors removed a 60.2-kilo (132-pound) tumor from a 51-year-old woman's ovaries, health officials said.
No intra-abdominal tumor this size has been documented before in the world, Moises Aaron Nuñez Gonzalez, director of IMSS Medical Unit No. 26 in the Cabo San Lucas Subzone, told reporters.
The operation was performed last month at a hospital in Cabo San Lucas, a city in Baja California Sur state.
The tumor in the patient, Mercedes Talamantes, began growing five years ago, Nuñez Gonzalez said.
The woman told Mexican media that it felt strange to walk without the huge bulge in her abdomen.
Talamantes said the tumor was making her depressed and her daughter convinced her to go see a doctor.
The operation on Talamantes lasted four hours, Nuñez Gonzalez said.