At construction sites, they called him Popeye.

With massive forearms and an iron grip, Robert Pendarvis seemed made for his job of cutting up sheet metal and wrestling heaters and air conditioners into place.

But his hands were not simply strong. They were doughy and thick, his ring finger growing 4½ sizes after he graduated from high school.

“Watch out when shaking hands with Rob,” a member of his church in Clinton, N.J., once joked. “It’s like shaking hands with a bunch of bananas.”

His feet started to grow as well. And alarmingly, so did his heart — to the point he eventually needed surgery to fix a leaky valve, and later was implanted with a defibrillator. Yet for years, no one put it all together, until Pendarvis started seeing a cardiologist he had known in high school.

Other classmates looked much as they had back then, just older, the doctor told him. You look different.

It turned out one phenomenon was behind all of it: the big hands, the big heart, and subtle changes in the shape of his jaw and other facial features — so gradual that even his wife, Sue, thought nothing of them. Pendarvis, blood tests would reveal, had a rare condition called acromegaly. And if not for that encounter with the high school friend who became a cardiologist, who hadn’t seen him in three decades, it might eventually have killed him.

Instead, the diseased heart went on display this year at the Mütter Museum, the collection of medical curiosities at the College of Physicians of Philadelphia. And Pendarvis, 60, who got a new heart during the first wave of COVID-19, survived to go see it.

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For centuries, physicians have reported rare cases of men and women with enlarged hands and feet, sometimes with a prominent jaw and nose. In a few instances, these people grew to a great height, with a condition called gigantism.

In the late 1800s, researchers found that these characteristics seemed to result from a tumor in the pituitary gland, a bean-size appendage of the brain found behind the eyes. But not until the mid-20th century did they figure out how.

They learned that the pituitary — which would be nicknamed the master gland — produces hormones to regulate a wide variety of bodily functions: metabolism, blood pressure, and reproductive cycles, to name a few.

“I think of it as the interface of the mind and the body,” says neurosurgeon Daniel F. Kelly, director of the Pacific Neuroscience Institute in Santa Monica, Calif.

But when the tiny bundle of cells is invaded by a tumor, hormone levels can go haywire. In patients with acromegaly — from the Greek for large extremities — the culprit is abnormally high levels of growth hormone.

When such tumors occur in children or adolescents, whose bones are still developing, the excess hormone can cause them to grow unusually tall. A famous case was the actor and wrestler known as André the Giant, who was listed at 7 feet 4 inches and more than 500 pounds.

More often, the tumors develop after people have stopped growing, and the bodily changes can be subtle. Patients commonly go a decade before being diagnosed — sometimes because they are unaware anything is amiss, other times because no one will listen.

Jill Sisco, president of Acromegaly Community, a support group, suffered from exhaustion so extreme that she likened it to the flu. But doctor after doctor failed to spot the cause. One was openly dismissive, she said, trotting out that tired old appraisal that it was “all in her head.”

“And it was in my head,” she said — in her pituitary.

Pendarvis also felt tired, often needing a midday nap. But the first sign anything was wrong came from his heart.

Pendarvis went to donate blood one time in 1998, at age 37, and got a surprise. The health-care worker who listened to his chest told him his heartbeat had an unusual murmur.

He followed up with a doctor’s appointment, and learned that his heart was enlarged. As a result his mitral valve, a pair of leaflets that open with every heartbeat, had started to leak. The surgery to repair it took place in 2002, in Colorado.

But the heart troubles continued. The organ began to beat irregularly, at times with a dangerous rhythm that put Pendarvis at risk of cardiac arrest. Physicians implanted a defibrillator in 2009.

Not until 2011, when he made an appointment with the physician he had known in high school, did it all start to make sense. Cardiologist Jon R. Sherman looked at his old classmate and thought his face and jaw seemed larger, even a bit “coarse,” he recalled. He also remarked that Pendarvis looked strong and fit yet said he tired easily. He asked his patient to get his hormone levels checked.

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Sure enough, they were off the charts. A tumor was the likely cause.

But Pendarvis could not get an MRI, as the machine’s powerful magnets could damage his defibrillator. Kelly, the Santa Monica neurosurgeon, had him get a CT scan instead, revealing just a shadowy outline of what looked like a tumor. It was enough to warrant a procedure.

In July 2012, Kelly and a colleague inserted a slender tool through Pendarvis’ nostrils, making a small incision at the back of the nasal cavity so they could reach the base of his brain. After three hours, they had extracted a tumor the size of a blueberry.

Some people who undergo this procedure continue to have high hormone levels and must keep them in check with medicines that can cost thousands of dollars a month. Pendarvis was lucky: His hormone levels subsided to normal within a day. Almost right away, the puffiness subsided in his fingers and face. And before long, his shoe size, having gone from 10 in high school to 12.5, dropped down to 11.

Even his tongue shrank a bit. He’d had sleep apnea before, and now it was gone.

But the damage to his heart was done. The technical term was dilated cardiomyopathy — and it was far worse than in most patients with acromegaly. Sherman, the cardiologist, told him one day he’d need a transplant.

From their old church in New Jersey, the Pendarvises were friends with Beth Lander, then a librarian at the College of Physicians. They were intrigued to hear about the medical oddities in the redbrick building where she worked in Center City. The Mütter had row upon row of human skulls. Slices of Einstein’s brain. Surgical instruments of long ago. And, in a glass case, the 19th-century skeleton of a “giant” — a man who’d had the same condition Pendarvis did: acromegaly. In that case, it developed when the man was still growing, and he reached a height of 7-foot-6.

When visiting Philadelphia in April 2019, the couple saw it all in person. Pendarvis, by then on his second defibrillator and knowing a transplant was in his future, had no hesitation. He said:

“My heart’s definitely got to go here.”

He first got on the transplant list in the New Orleans area, where he and Sue had moved to be near their daughter and son-in-law. When the young couple moved to North Carolina for a job, the Pendarvises followed, switching to the transplant list in that state.

In both states, when talking to the surgeons who would do the procedure, the patient and his wife were adamant: The heart had to go to the Mütter Museum. In July 2020, on the day of the actual surgery at Duke University Hospital, in Durham, Pendarvis even brought a plastic container to put it in.

Afterward, when surgeon Jacob N. Schroder came to check on his patient, he heard the pleas again.

“Their only concern was, ‘Is the heart on its way to Philadelphia?’” the physician recalled. “Not ‘How am I doing?’”

Anna Dhody, the curator of the Mütter Museum, spent months preparing for the big day. She exchanged calls and emails with Pendarvis’ physicians, coordinated with hospital pathologists, and got the lab ready to preserve an unusual human organ.

She decided to make a production of it, unboxing the heart in a YouTube video that has now gotten 350,000 views. Cutting through a layer of red, bio-waste plastic inside to reveal a plastic container inside, she seemed a bit nonplussed.

“This is super exciting,” she says in the video, wearing gloves and a mask to protect herself from preservative fumes. “This also really looks like some Tupperware I own, which is slightly disconcerting.”

The heart was vacuum-sealed and had become compressed, looking almost like a slab of meat. Which of course, it was.

Collections manager Lowell Flanders took it from there. He injected the dense tissue with formalin, an antiseptic. He then placed the heart in a formalin bath for 48 hours, followed by a water bath, causing it to expand to its original size. He then swapped in a solution of ethanol, to better preserve the heart for the long term.

Pendarvis could not come see his own heart for a while. He developed an infection and other complications after his transplant, spending a grueling three months in the hospital. The new heart works well, and his hormone levels remain normal. But he is still weak from his medical ordeal, tiring easily and struggling with his balance. He finally made it to Philadelphia the day his old heart went on display, in July — a year after the surgery.

Though enthusiastic, he was a little nervous until he met Dhody and Flanders, who calmly described their careful preparations.

And then he saw it, alongside the bones and other relics of medicine from long ago: his old heart, nearly twice the size of the new one that now beat in his chest.

“Surreal,” he said. “I’m still alive, but the thing that kept me alive all those years is sitting there in a glass box.”

While at the museum, he agreed to be interviewed on camera for more than an hour — a gift of knowledge, Dhody said later, that was as precious as the organ itself.

Pendarvis was happy to do it. The heart ended up in the box because it failed him, after decades when no one knew what was wrong. By sharing the story that goes with it, he hopes that others — perhaps someone with massive forearms — will get help before it’s too late.