Introduction: Central nervous system (CNS) actinomycosis typically presents from the local spread of
infection via the ear, sinus, or cervicofacial region, resulting most commonly in abscesses. Only one other
case report reports on cerebral abscess with Actinomyces odontolyticus.
Presentation of Case: A 60-year-old male presented with cognitive impairment and speech difficulties.
Imaging revealed a cerebral abscess in the left temporal lobe causing significant mass effect and uncal
herniation. Bony erosion was noted along the middle cranial fossa with fluid attenuation of the middle ear
and mastoid. An emergent surgery was performed with neurosurgery and otolaryngology. Initially, a left
craniotomy was performed in order to obtain access to the left temporal lobe. A vascularized flap was
harvested from the fascia of the temporalis in order to repair any defects along the middle cranial fossa. The
abscess was drained using ultrasound guidance. A mastoidectomy was then performed for source control.
Cultures revealed Actinomyces odontolyticus for which intravenous antibiotics were administered. The
patient developed postoperative seizures requiring monitoring and anti-epileptic medication. Follow-up
revealed continued improvement in the patient’s cognition.
Discussion: Cerebral abscess in the temporal lobe along the floor of the middle cranial fossa can be due to
direct extension of infection from the middle ear or mastoid which requires a multidisciplinary approach to
surgical treatment. Actinomycosis is a rare pathogen for CNS infection with only one other case report of
CNS Actinomyces odontolyticus. Postoperative care in regards to antibiotic treatment and follow-up are also
reviewed.
Conclusion: The case highlights the urgency of treatment and surgical decision making made
intraoperatively by both neurosurgery and otolaryngology in regards to drainage, repair of the defect, and
treatment of infectious source.