Melania Trump returned to the White House in "high spirits" on Saturday following a weeklong hospitalization for kidney treatment, a lengthy stay that raised questions about whether the first lady's condition may have been more complicated than first revealed.

President Donald Trump heralded her homecoming with a tweet that referred to her as "Melanie" instead of "Melania."

"Great to have our incredible First Lady back home in the White House. Melanie is feeling and doing really well. Thank you for all of your prayers and best wishes!" Trump wrote before quickly superseding that tweet with another that spelled his wife's name correctly.

Mrs. Trump's quiet return to the White House, her husband and their 12-year-old son, after five days at a nearby U.S. military hospital resolved a brewing mystery about when she would eventually be released. What remain are questions about the state of her health.

Her spokeswoman, Stephanie Grisham, has declined to release additional details, citing Mrs. Trump's right to privacy.

"The First Lady returned home to the White House this morning," Grisham said in an emailed statement. "She is resting comfortably and remains in high spirits. Our office has received thousands of calls and emails wishing Mrs. Trump well, and we thank everyone who has taken the time to reach out."

First ladies are under no obligation to make their medical histories public.

She had been at Walter Reed National Military Medical Center near Washington since Monday, when she had an embolization procedure to treat an unspecified kidney condition the White House described as benign. Word of the hospitalization came as a surprise as there was no indication during her public appearances in recent weeks, including during a state visit by France's president, that Mrs. Trump had been ailing.

One week before the procedure, a beaming Mrs. Trump, 48, presided over a splashy announcement ceremony in the White House Rose Garden to introduce her "Be Best" public awareness campaign to help teach kindness to children.

Grisham said Monday that the procedure was "successful," there were no complications and that Mrs. Trump would probably remain hospitalized for "the duration of the week."

The president then tweeted Tuesday that his wife would be released in "2 or 3" days, but Thursday and Friday passed without word from the White House on her whereabouts. Trump had visited her during her first three days of hospitalization. But he did not visit Thursday or Friday, leading some to wonder whether that meant the first lady had been discharged.

The first lady said Wednesday on Twitter that she was "feeling great" and looking forward to going home, but gave no indication of when that might happen. On Friday, she tweeted about the deadly school shooting at a Houston-area high school but did not update her followers on her medical situation.

Urologists with no personal knowledge of Mrs. Trump's condition said the most likely explanation for the procedure is a kind of noncancerous kidney tumor called an angiomyolipoma. They're not common but tend to occur in middle-aged women and can cause problematic bleeding if they become large enough, said Dr. Keith Kowalczyk of MedStar Georgetown University Hospital.

Doctors often treat the condition by cutting off the blood supply so the growth shrinks, added Dr. Lambros Stamatakis of MedStar Washington Hospital Center. That is done with an embolization, meaning a catheter is snaked into the blood vessels of the kidney to find the right one to block.

Most of the time, these tumors are found when people undergo medical scans for another reason, but sometimes people have pain or other symptoms, Kowalczyk said. Many times, embolization patients go home the same day or the next.

Grisham on Saturday characterized speculation about the first lady as "uninformed," adding that every patient is different.

"Mrs. Trump has a medical team that is comfortable with her care, which is all that matters," she said. "Her recovery and privacy are paramount and I will have no further comment beyond this."

The question of what level of accountability should be expected of first ladies is difficult because they are private citizens, yet public figures who draw keen interest from the public, have taxpayer-supported staff and sometimes involve themselves in politics and policy.

Myra Gutin, a Rider University professor who studies presidents' wives, recalled the backlash Rosalynn Carter suffered for attending Cabinet meetings; she explained that she just wanted to get things right because she was so often out and about representing President Jimmy Carter.

The White House has a mixed record on disclosing information about the ailments of first ladies.

Nancy Reagan revealed in 1987 that she had breast cancer and had her left breast surgically removed.

But nearly two decades later, the White House found itself on the defensive for its after-the-fact disclosure that Laura Bush had skin cancer removed from her right shin in November 2006.

Mrs. Bush had decided it was a private matter, but it nonetheless came to light after she was seen wearing a bandage below her right knee.

The following year, the White House proactively disclosed that Mrs. Bush would have surgery to relieve pain from pinched nerves in her neck. The problem kept her from accompanying President George W. Bush on a trip to Australia.

Sheila Tate, a press secretary to Mrs. Reagan, said the first lady felt it was appropriate to reveal her breast cancer diagnosis.

Such disclosures by a first lady aren't "absolutely required, by any means," Tate said. "Melania is entitled to her privacy, if that's what she wants."

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AP Medical Writer Lauran Neergaard contributed to this report.

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