Syphilis is a systemic infection caused by the bacterium Treponema pallidum. If left untreated, it progresses through distinct clinical stages. After the highly infectious primary and secondary stages (marked by chancres and rashes), the infection can enter a period of latency where symptoms disappear, but the bacteria remain. For approximately one-third of untreated individuals, the disease progresses to the final and most destructive stage, known as tertiary syphilis. This advanced stage is characterized by the formation of a specific lesion called a gumma, a severe, late-stage manifestation of the infection.
Defining the Gumma and Staging
A gumma is a distinctive, soft, tumor-like growth resulting from a specific inflammatory response against persistent Treponema pallidum. Pathologically, it is a granuloma—a collection of immune cells attempting to wall off the infection. The core often contains a rubbery mass of dead tissue, exhibiting a unique type of necrosis that helps distinguish it from other diseases.
The formation of a gumma is the hallmark of late, or tertiary, syphilis, sometimes called gummatous syphilis. These lesions typically appear years, or even decades, after the initial infection. This late-stage manifestation is a result of a delayed hypersensitivity reaction to the small numbers of spirochetes remaining in the tissue.
While bacteria are scarce within a gumma, the lesion itself is not infectious. Gummas signal a localized, destructive inflammatory response where the immune system failed to clear the pathogen. They are considered a form of late syphilis that usually does not immediately endanger the patient’s life, unlike cardiovascular or neurological forms of tertiary disease.
Clinical Appearance and Locations of Gummas
Gummas can develop almost anywhere, but they most commonly affect the skin, mucous membranes, bones, and internal organs, particularly the liver. Their appearance is highly variable depending on the location and the tissue invaded. On the skin, they often begin as non-tender, deep subcutaneous nodules that gradually enlarge.
As they progress, cutaneous gummas can break down, forming large, punched-out ulcers with thick, necrotic bases and irregular borders. These open sores are generally painless but can be highly disfiguring, leading to significant scarring upon healing. Mucous membrane gummas, often found in the mouth or throat, can similarly ulcerate and cause local tissue destruction.
When gummas form in the bone (syphilitic osteitis), they cause deep pain, often worse at night. The destructive nature of the lesion can lead to structural damage, such as perforation of the nasal septum, potentially causing a saddle nose deformity. In the liver, gummas are referred to as hepar lobatum, where healing results in severe scarring and fibrosis that distorts the organ’s structure.
The primary concern of gumma formation is their destructive potential through tissue necrosis and subsequent scarring. This damage can seriously impair organ function. The lesions range dramatically in size, and their slow growth and healing leave behind permanent fibrous scars.
Diagnosis and Recommended Treatment
Diagnosing a gumma relies on clinical suspicion, characteristic pathology, and serological evidence of long-standing syphilis infection. Because their appearance varies, gummas are often confused with other conditions, making laboratory confirmation essential. The diagnostic workup begins with serological tests for syphilis, divided into non-treponemal and treponemal tests.
Non-treponemal tests, such as the VDRL or RPR, are used for screening and monitoring disease activity. Positive screening results are confirmed using specific treponemal tests, like the FTA-ABS or TP-PA assay. A tissue biopsy may also be performed, which reveals the characteristic granulomatous inflammation and central necrosis specific to a gumma.
The definitive treatment for late/tertiary syphilis is a longer course of penicillin G compared to earlier stages. Current guidelines recommend three weekly intramuscular injections of 2.4 million units of Benzathine Penicillin G. This extended regimen is necessary because the spirochetes in this stage divide more slowly, requiring sustained antibiotic levels.
All patients diagnosed with tertiary syphilis, including those with gummas, should undergo a thorough evaluation for neurosyphilis, potentially involving a cerebrospinal fluid examination. Following treatment, patients require careful follow-up with serial non-treponemal test titers to monitor the therapeutic response. A successful outcome is indicated by a fourfold decline in the titer within 12 to 24 months.