A 27-year-old man went to the hospital with three days of worsening pain in the lower right side of his abdomen, along with nausea, vomiting, and loss of appetite. Everything pointed to appendicitis, one of the most common reasons for emergency abdominal surgery.
When surgeons opened his abdomen, his appendix was normal. Instead, they found a giant mass measuring about 11 by 13 by 12 centimeters, twisted 540 degrees on its cord. It was his right testicle, which had never descended into the scrotum and had become cancerous.
Urologists at Southern Philippines Medical Center in Davao City described the case in July in Urology Case Reports, calling it "the great pretender" and "a rare diagnostic trap."
A Classic Appendicitis Picture with One Missed Clue
On examination, the man had tenderness and signs of inflammation in the lower right abdomen. His white blood cell count and C-reactive protein, a marker of inflammation, were elevated, and he scored 7 on the Alvarado score, a tool doctors use to estimate the likelihood of appendicitis. That score indicates high suspicion.
But the exam also showed something else: his right testicle was absent from the scrotum. The authors wrote that "the most important missed diagnostic clue was the absent ipsilateral testis," meaning the testicle on the same side as the pain. The report does not say whether the man knew he had an undescended testicle or whether it had ever been treated.
He was taken for emergency exploratory surgery, and the report describes no imaging beforehand. Surgeons found the mass with a 540-degree twist, about one and a half full turns, in the spermatic cord, the structure that carries blood to the testicle. Twisting, called torsion, cuts off that blood supply and causes intense pain. The authors described the situation as "simultaneous ischemic and oncologic emergencies."
Pathology Confirmed a Seminoma
Urologists called into the operating room removed the testicle. Laboratory analysis identified a classic seminoma, a type of germ cell tumor that the authors say predominates in untreated undescended testicles after puberty. The tumor had invaded several nearby structures, including small blood and lymph channels, but the surgical margin was clear.
A blood marker called lactate dehydrogenase was elevated before surgery and returned to normal afterward. A CT scan of his chest and abdomen showed no spread to lymph nodes or distant organs. The cancer was classified as stage IB, and he was referred for active surveillance, meaning close monitoring rather than immediate chemotherapy or radiation.
His diagnosis, surgery, and staging were all completed during a single emergency admission.
Undescended Testicles Carry a Known Cancer Risk
Undescended testicles, known medically as cryptorchidism, are common at birth. According to the American Urological Association, they occur in 1% to 3% of full-term and 15% to 30% of premature male infants, though many descend on their own in the first months of life.
The authors called cryptorchidism "the strongest established congenital risk factor for testicular germ cell tumors,"with an approximately 3.7- to 7.5-fold increased lifetime risk compared with the general population. Even so, they noted that the absolute lifetime risk remains about 2% to 5%. Testicles located inside the abdomen carry the highest risk.
According to the National Library of Medicine's StatPearls review, about 20% to 30% of undescended testicles cannot be felt on examination, often because they sit higher in the groin or inside the abdomen.
Timing of treatment matters. A landmark Swedish study of nearly 17,000 men, published in the New England Journal of Medicine in 2007, found that men who had surgery to bring down an undescended testicle before age 13 had about twice the testicular cancer risk of the general population, compared with more than five times the risk for those treated at 13 or older. The Karolinska Institutet researchers followed the men for nearly 210,000 person-years and identified 56 testicular cancers.
The AUA recommends that if a testicle has not descended by 6 months of age, corrected for prematurity, surgery should be performed within the following year. Early surgery lowers but does not eliminate the later cancer risk.
A Reminder That Can Save Time in the Emergency Room
Testicular cancer is relatively uncommon but strikes young men. The National Cancer Institute estimates about 9,810 new cases in the United States in 2026, with 51% of cases diagnosed between ages 20 and 34. Five-year relative survival is 94.6%.
Because appendicitis is so common, the authors warned, rarer conditions that look identical can lead clinicians into "diagnostic anchoring bias," settling on the first likely explanation.
Their main recommendation is simple: "Routine examination of the external genitalia should be performed in every male patient presenting with acute abdominal pain."
For men, the case is a reminder that an undescended or missing testicle is worth discussing with a doctor at any age. The American Cancer Society estimates that about 1 in 250 males will develop testicular cancer during their lifetime, and most cases are highly treatable.
Key Questions Answered
What did surgeons find?
Instead of an inflamed appendix, they found a roughly 13-centimeter cancerous testicle inside the man's abdomen, twisted 540 degrees on its blood supply.
Why did it look like appendicitis?
The mass sat in the lower right abdomen and caused pain, vomiting, loss of appetite, and raised inflammation markers typical of appendicitis.
What was the missed clue?
His right testicle was absent from the scrotum. The authors recommend examining the genitals in every male with acute abdominal pain.
What type of cancer was it?
A classic seminoma, stage IB, with no spread detected on CT scans. He was referred for active surveillance after the testicle was removed.
Do undescended testicles raise cancer risk?
Yes. The authors cite a roughly 3.7- to 7.5-fold higher risk, though the absolute lifetime risk remains about 2% to 5%. Surgery before puberty lowers, but does not eliminate, that risk.
Published by Medicaldaily.com
