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Cryptic presentation: primary amoebic meningoencephalitis mimicking a high-grade malignancy resulting in surgical

M Kodeeswaran1, Gaurav R Dhoka1, Jamila Alagarsamy2

  • 1Departments of Neurosurgery, Government Kilpauk Medical College and Hospital, Kilpauk, Chennai, Tamil Nadu, India.

Journal of Neurosurgery. Case Lessons
|January 20, 2025
PubMed
Abstract

Insights

Primary amoebic meningoencephalitis (PAM) was unexpectedly diagnosed postmortem in a patient presenting with a space-occupying brain lesion. This rare case highlights PAM

Area of Science:

  • Neurology
  • Infectious Diseases
  • Pathology

Background:

  • A 71-year-old male presented with a 3-month history of right upper limb weakness and headache.
  • Brain MRI revealed a left frontal space-occupying lesion, initially suspected to be high-grade malignancy.
  • The patient underwent awake craniotomy with lesion excision under immunofluorescence guidance.

Purpose of the Study:

  • To report an exceedingly rare and unprecedented case of primary amoebic meningoencephalitis (PAM).
  • To describe the diagnostic challenges and unique presentation of PAM mimicking a malignant brain tumor.

Main Methods:

  • Clinical presentation and neuroimaging findings were analyzed.
  • Surgical excision of the brain lesion was performed.
  • Postoperative course and histopathological analysis were reviewed.

Main Results:

  • The lesion showed fluorescence uptake intraoperatively, consistent with the surgical guidance.
  • Postoperatively, the patient developed meningoencephalitis and succumbed to the infection.
  • Histopathology confirmed an abscess with parasitic infection, identifying Naegleria fowleri as the causative agent of PAM.

Conclusions:

  • PAM can present atypically as a space-occupying lesion, mimicking high-grade malignancy.
  • The nonspecific initial symptoms and misleading imaging findings contributed to diagnostic delay.
  • This case underscores the importance of considering rare infectious etiologies even with seemingly neoplastic presentations.
Keywords:
cryptic presentationhigh-grade malignancyprimary amoebic meningoencephalitisspace-occupying lesion

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