Cerebral syphilis mimicking metastatic tumors: Report and review of the literature
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.237026
Source of Support: None, Conflict of Interest: None
Syphilis is a sexually transmitted infectious disease caused by the spirochetal bacterium Treponema pallidum. It affects many organs and systems and simulates other diseases. It is misdiagnosed easily, especially when a cerebral gumma is present. The pathology of gummas is characterized by granulomatous inflammatory lesions, accompanied by distinct microvascular changes. We describe a patient with neurosyphilis presenting as multiple central lesions and having the characteristic findings on cerebrospinal fluid (CSF) analysis.
A 52-year old woman presented with headache and dizziness for 3 months. The headache was constant and extending in intensity from very mild to severe attacks of pain of 3–5 min duration, occurring 5–10 times a day, with no clear trigger. Her neurological examination was normal.
Blood tests were normal including the complete blood count, serum electrolytes, liver function tests, blood urea nitrogen, and serum creatinine. Human immunodeficiency virus (HIV) test was negative, but rapid plasma reagin (RPR) test was 1:16 with a positive Treponema pallidum hemagglutinationassay (TPHA) in serum. Magnetic resonance imaging (MRI)of the head demonstrated multiple sites of involvement in the left basal ganglia and thalamus, corpus callosum, and left frontal lobe areas [Figure 1]. Magnetic resonance spectroscopy (MRS) of the tumor demonstrated a higher choline (cho), an N – acety aspartate (NAA) decline and a lipid peak on the left side of the spectrum, particularly in the basal ganglia-thalamic lesions.
We made a presumptive diagnosis of the presence of a metastatic tumor and a craniotomy was performed with the intention to obtain a biopsy of the lesion. The mass was found to be gray and hard, and was attached to the left insular lobe. The size of the mass was approximately 1.5 cm × 1.5 cm × 1.5 cm, and there was no differentiation of the mass from the surrounding brain tissue. The surface of the cerebral cortex surrounding the lesion was edematous but was not tightly adherent to the tumor. Postoperatively, CSF cytology revealed a red blood cell (RBC) count of 0 cells/mm 3, a white blood cell (WBC) count of 3 cells/mm 3, the protein level of 107.87mg/L, the CSF IgG level of 188mg/L (12.0–33.0), the CSF albumin synthetic index of 1.04 (<0.7), and normal chloride, glucose and lactate values. In addition, the results of TPHA and rapid plasma reagin (RPR) tests were positive (RPR1:4). Histopathological examination of the mass showed granulomatous inflammation with a large number of lymphocytes and plasma cells and the presence of vasculitis; the peripheral region had become fibrotic. These findings were consistent with the presence of a cerebral gumma [Figure 2].
The patient was finally diagnosed with neurosyphilis. Based on this diagnosis, she was treated with water-soluble penicillin-G administered intravenously in a daily dose of 24 × 106 U for 14 days postoperatively. Thereafter, intramuscular benzathine penicillin of 2.4 million units once per week was injected for 3 weeks. The headache and dizziness disappeared, and there were no other neurological deficits. The patient was, therefore, discharged and was placed under follow-up care.
Neurosyphilis can manifest as a neurological disease; however, the diagnosis is difficult to establish because many of the patients are asymptomatic. Cerebral syphilitic gumma is a presentation of neurosyphilis which is considered to be a rare involvement of the brain. It is a mass of granulation tissue showing infiltration of the brain by lymphocytes and plasma cells, with fibrosis and necrosis that typically arises from the dura mater and pia mater and is detected as a cortical mass., Therefore, it often mimics an intracranial tumor. Cerebral gumma is frequently diagnosed at the time of surgery when an inflammatory lesion is found on frozen section.
An isolated intracranial gummatous lesion or multiple similar lesions, occurring either in the immunocompromised or the immunocompetent patients, who are treated using penicillin, are rare findings. To date, nine cases have been published [Table 1]. In contrast to our patient, in the other patients having the presence of a cerebral syphilitic gumma, the lesions mostly occurred at cerebral convexities, especially in the report by Fargen et al.,,,,,,,,,
Radiological testing can often be misleading. Case reports of MRI findings in cerebral gumma have revealed T1-weighted hypo- or isointensity with T2-weighted hyperintensity. The CSF analysis showed that the venereal disease research laboratory (VDRL) test of some of the patients was negative. Therefore, in HIV or non-HIV patients, a normal CSF picture does not exclude the presence of neurosyphilis. Therefore, to unequivocally establish the presence of a neurosyphilitic gumma, a pathologic diagnosis is mandatory.
In summary, our report demonstrates that a normal CSF does not exclude the presence of neurosyphilis. Syphilitic gummata should be included in the differential diagnosis of space-occupying lesions, such as tuberculosis, toxoplasmosis, cryptococcosis, histoplasmosis and intracranial neoplasms.
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There are no conflicts of interest.
[Figure 1], [Figure 2]