Ruptured Aorta’s ‘Tree Bark’ Texture Unveils Untreated Syphilis After Severe Crash

A man in his fifties sustained a severe chest impact against a brick wall during a vehicle collision. He experienced chest pain and systemic malaise, ultimately succumbing to cardiac arrest weeks later while hospitalized.

During the autopsy, pathologists discovered that the man’s aorta had ruptured. The inner lining exhibited a bumpy, irregular, and wrinkled texture historically compared to tree bark—a classic indicator of an infection rarely associated with the heart: untreated syphilis.

This case is detailed in an abstract titled “Barking up an unusual tree,” published in Pathology, the journal of the Royal College of Pathologists of Australasia. The authors concluded that the findings were most indicative of syphilitic aortitis, a rare late-stage complication of the infection.

What the Autopsy Revealed

The patient’s known medical history was limited. According to the abstract, it included a history of illicit drug use and immigration to Australia from Asia over two decades prior.

The autopsy revealed an aneurysm, or abnormal bulge, in the aortic arch where a rupture point was sealed by a blood clot. Additionally, approximately 3 liters of blood accumulated in his left hemithorax. He also suffered an extensive type B aortic dissection, a tear allowing blood to force its way between the layers of the aortic wall, specifically affecting the descending aorta.

The outer layer of the aorta was significantly thickened, while the inner lining displayed the characteristic bumpy wrinkling that gives the tree-bark pattern its name. Microscopic examination revealed ulcerated calcium deposits in the lining, fragmented elastic fibers, inflammation narrowing small arteries, and scarring of the outer wall.

The abstract describes these features as hallmarks of aortitis, most suggestive of syphilis rather than a confirmed diagnosis. It does not report laboratory confirmation of the infection, nor does it detail the exact contribution of the crash to his death.

Why Syphilis Can Cause the Aorta to Look Like Bark

Aortitis, or inflammation of the aorta, is uncommon. The authors note that it can arise from Takayasu’s arteritis, tuberculosis, tertiary syphilis, and certain bacterial or fungal infections, potentially leading to narrowing, aneurysm, dissection, and rupture. However, the tree-bark appearance specifically refers to syphilitic aortitis.

A decades-old specimen in the CDC’s public image library illustrates this same effect, which the agency describes as markedly irregular wrinkling of the aorta’s inner lining in cardiovascular tertiary syphilis.

Tertiary syphilis represents the late stage of an infection that was never adequately treated. In its laboratory recommendations for syphilis testing, the CDC identifies it as a rare condition whose cardiovascular form can produce aneurysms or narrowing as the syphilis bacteria multiply within the thoracic aorta or coronary arteries. The gap between the secondary and tertiary stages can span years or decades, and in up to two-thirds of patients, the infection remains latent for life and never progresses.

A Rare Complication Amid Persistently High Syphilis Rates

While the case originates from Australia, it carries significant weight in the United States, where syphilis rates have climbed for years.

The CDC’s most recent national figures—provisional 2024 data from its national STI surveillance report released in September 2025—indicate some progress: primary and secondary syphilis, the most infectious stages, fell 22% from 2023, marking a second consecutive year of decline. However, congenital syphilis rose for the 12th consecutive year, reaching nearly 4,000 cases, which is nearly 700% higher than a decade earlier. Furthermore, reported cases of late syphilis or syphilis of unknown duration more than doubled between 2020 and 2024, increasing from approximately 47,000 to roughly 97,000.

Treatment supply presents another significant pressure point. The CDC’s syphilis treatment guidance notes that on March 6, 2026, the FDA permitted the temporary importation of Lentocilin due to the ongoing limited availability of Bicillin L-A, the long-acting penicillin injection used to treat syphilis. The CDC has urged jurisdictions to preserve the drug for pregnant patients, and recent state health department updates project that the Bicillin L-A supply will not fully recover until late 2027.

A Rare Finding with a Simple Takeaway

This represents a single autopsy case detailed in a brief abstract, and it should not be interpreted as evidence that syphilitic aortitis is becoming common. The diagnosis relies on the tissue’s appearance and microscopic features, which the authors describe as most suggestive of syphilis.

The authors present it as an unusual etiology to consider when evaluating aortic aneurysms and dissections.

For the public, the practical lesson remains familiar. Syphilis is diagnosed through blood tests and treated with penicillin, which aims to clear the infection and prevent long-term damage to the heart, brain, and blood vessels. Individuals who may have been exposed should consult a clinician regarding testing. Anyone experiencing chest pain after trauma, or sudden severe chest or back pain, should seek emergency medical care immediately.

Key Questions Answered

What is a tree-bark aorta?

It describes an aorta whose inner lining is wrinkled and ridged like bark, a pattern classically associated with syphilitic aortitis.

What happened to the man in this case?

After striking his chest in a car crash, a man in his 50s had chest pain and, weeks later, a fatal cardiac arrest in the hospital. Autopsy showed a ruptured aortic arch aneurysm and an extensive type B dissection.

Was syphilis confirmed?

No. The authors describe the findings as most suggestive of syphilitic aortitis, and the abstract does not report laboratory confirmation.

How does syphilis damage the aorta?

Untreated syphilis can progress over years or decades to tertiary disease, which may affect the thoracic aorta and cause aneurysms or narrowing. Most untreated infections never reach this stage.

Can syphilis be stopped before it reaches this stage?

Yes. Syphilis can be detected with blood tests and treated with penicillin, and treatment helps prevent late complications.

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