A 22-year-old man in Italy had a penile bump that kept growing and stayed inflamed, even after several courses of antibiotics. When surgeons finally removed it, the cause turned out to be hair that had worked its way into his skin and set off a chronic inflammatory reaction.
The diagnosis was a pilonidal sinus, a condition usually found in the cleft between the buttocks. Doctors at San Carlo di Nancy Hospital in Rome described the case in a report in the Journal of Surgical Case Reports published July 21. According to the authors, only 29 cases of pilonidal disease of the penis have been reported in the medical literature.
A Pinpoint Opening Antibiotics Could Not Fix
The patient had no relevant medical history. He was referred urgently to the hospital's urology unit with what the authors called "a long-standing suspicious penile lesion" that had been growing steadily and showed local inflammation. Several courses of antibiotics had brought "no significant improvement."
On examination, doctors found "a white, indurated papule with a central pinpoint orifice." In plain terms, it was a firm, pale bump with a tiny hole in the middle. It sat on the upper side of the balanopreputial fold, the area where the foreskin meets the head of the penis. There were no swollen lymph nodes in his groin, a finding doctors check when a penile lesion raises any concern about cancer.
The failure of antibiotics makes sense in hindsight. A pilonidal sinus is driven by embedded hair, which acts as a foreign body. Antibiotics can calm an infection around it, but they cannot remove the hair that keeps the inflammation going.
Surgery Found a Lesion Stuck to Delicate Structures
The operation proved more involved than the small bump suggested. The lesion was densely stuck to nearby tissue, including the tunica albuginea, the tough sheath around the penis's erectile tissue, and the penile neurovascular bundle, which carries the nerves and blood vessels essential to sensation and function.
Surgeons performed a radical sleeve circumcision, removing the foreskin along with the lesion, and reconstructed the penis.
Under the microscope, pathologists saw "a terminal hair embedded within the epidermis," along with multinucleated giant cells in the deeper skin layer. These are fused immune cells the body forms when it tries to wall off something it cannot break down. Free hair shafts also ran through the inflamed area, surrounded by a dense cluster of lymphocytes, a type of white blood cell. That pattern confirmed the diagnosis.
The patient recovered without complications, and his symptoms did not return during follow-up.
A Condition Better Known as "Jeep Disease"
Pilonidal disease is common in its usual location. StatPearls, a clinical reference hosted by the National Library of Medicine, puts its incidence at about 26 per 100,000 people, with roughly 70,000 people affected each year in the United States. It affects men about 2.2 times as often as women. So many U.S. soldiers developed it during wartime that it earned the nickname "Jeep disease." In its typical form, it is a fluid-filled pocket that forms around a hair follicle in the crease between the buttocks.
Experts now consider it an acquired condition rather than one present from birth. In the most widely accepted theory, local friction and pressure drive hairs into the skin, triggering a foreign-body reaction that can lead to infection and abscesses. The Rome team noted a second theory, in which shed hairs from other parts of the body become trapped inside a developing cavity under the skin.
Unusual locations have been documented before. The Rome authors list the navel, the area above the pubic bone, the external genitalia, the armpit, the breastbone, the breast and the clefts between fingers. StatPearls notes that the finger form appears in barbers, hairdressers, and animal groomers, who handle clipped hair all day.
The penis remains one of the rarest sites. Reported penile cases range in age from 19 to 61, and most appear on the upper side of an uncircumcised penis near the coronal sulcus, the groove behind the head. Earlier reports include one penile case that mimicked carcinoma and a 2025 penile case in a circumcised man.
A Rare Diagnosis Doctors Want on the List
The authors' main concern is that the condition is easy to miss because few clinicians expect it. A long-lasting, inflamed penile bump could be mistaken for balanoposthitis, an inflammation of the head and foreskin, or for hidradenitis suppurativa, an epidermoid cyst, follicular occlusion disorders, or penile cancer.
Examining the removed tissue is what settles the question. The authors wrote that histopathology, performed in nearly all reported cases, "remains the diagnostic gold standard." Because the condition can mimic both harmless and malignant lesions, they concluded that it "should be considered in the differential diagnosis of penile masses to facilitate timely management and reduce morbidity."
Risk factors cited in the report include a sedentary lifestyle, higher body mass index and heavy body hair. The report does not say which, if any, applied to this patient, and a single case cannot show how often penile pilonidal disease goes unrecognized.
For men, the takeaway is practical rather than alarming. A penile bump that keeps growing, drains, or does not improve with treatment deserves a follow-up visit with a urologist or dermatologist, both to find the cause and to rule out more serious conditions.
Key Questions Answered
What did doctors find?
A pilonidal sinus on the penis of a 22-year-old man, with hair embedded in the skin and surrounded by chronic inflammation.
What is a pilonidal sinus?
It is a small tract or pocket in the skin caused by trapped hair that triggers a foreign-body reaction. It usually forms in the cleft between the buttocks.
Why didn't antibiotics work?
Antibiotics can treat surrounding infection but cannot remove the embedded hair driving the inflammation. Surgical removal is the definitive treatment.
How rare is it on the penis?
Very rare. The authors found only 29 cases reported in the medical literature.
What could it be mistaken for?
Balanoposthitis, hidradenitis suppurativa, epidermoid cysts, follicular occlusion disorders, and penile cancer. Tissue examination confirms the diagnosis.
Did the patient recover?
Yes. He healed without complications after circumcision and reconstruction, with no return of symptoms during follow-up.
Published by Medicaldaily.com
