Mexican President Enrique Pena Nieto will be operated on next week to have a benign thyroid nodule removed just months after the 47-year-old was sworn in.
"On Wednesday July 31, President Enrique Pena Nieto will undergo surgery to have removed a thyroid nodule" the statement said, without offering more details on the president's condition.
A presidential spokesperson later emphasized that the nodule was benign "as determined by a biopsy" in Mexico City recently.
A nodule is a small lump which was found on the gland which regulates hormones, located at the base of the neck just above the breastbone.
The vast majority of nodules cause no symptoms, but a small percentage are cancerous, and nodules can grow large enough to cause pressure and make it difficult to swallow.
The operation at Central Military Hospital should last about 90 minutes, and Pena Nieto will then take four days to recover during which he will hold only private meetings, his office said.
Earlier this month the youthful, photogenic president finished a 10-kilometer race in Mexico City in 54:08 minutes.
He took office in December, returning the Institutional Revolutionary Party (PRI) to power after 12 years on the sidelines.
The surprise announcement of presidential medical woes came as Pena Nieto juggled a violent uprising in Michoacan, and a prominent US visitor.
Earlier Wednesday Pena Nieto met briefly at the Los Pinos presidential palace with visiting US Homeland Security Secretary Janet Napolitano.
On Tuesday, the United States and Mexico signed an agreement on joint border patrols and information exchanges.
Under Pena Nieto's predecessor, Felipe Calderon, gang violence surged throughout Mexico leaving 70,000 people dead by the time Calderon left office in December, while a powerful new cartel, the Knights Templar, emerged in Michoacan.
On Tuesday at least 22 people were killed in clashes in the western state as federal authorities square off in clashes with suspected members of teh Knights Templars organized crime ring.
Security forces in a Mexican state plagued by drug violence were working to restore order on Wednesday.
The clashes in the troubled Tierra Calienta region were the worst since the army and federal police launched a joint operation in May to protect the local population from the notorious Knights Templar cartel.
Pena Nieto has said his strategy will be different than his predecessor's, with a single command, close coordination between various authorities, greater use of intelligence assets, and an economic development program.
He has also since launched a crime prevention program, but he says military troops deployed by Calderon will stay on the ground until the murder rate declines.
Fed up with crime, vigilantes have appeared in recent months and clashed with the Knights Templar cartel, notably in Tierra Caliente.
Drug gangs have existed for decades in Michoacan, where they grow marijuana and opium poppies and produce synthetic drugs in makeshift labs before shipping them to the United States.