Intracranial Actinomycosis Manifesting as a Parenchymal Mass Lesion: A Case Report and Review of Literature.

BACKGROUND: Intracranial actinomycosis is a rare bacterial infection with no characteristic clinical or radiologic diagnostic features. The usual presentation is similar to pyogenic brain abscess or osteomyelitis with or without pachymeningitis. Intracranial actinomycosis rarely manifests as a parenchymal mass lesion. A high index of suspicion is warranted in a patient with immunosuppression or predisposing factors, such as dental procedure, sinusitis, cardiac septal defect, craniofacial trauma, cranial surgery, lung infection, or abdominopelvic infection.

CASE DESCRIPTION: A young woman presented with a right parietal parenchymal lesion with involvement of the calvaria and pericranium. She had no predisposing factors for intracranial actinomycosis. She underwent complete microsurgical excision of the lesion followed by prolonged antibiotic therapy. She experienced a good functional recovery.

CONCLUSIONS: Intracranial actinomycosis manifesting as a parenchymal mass lesion is extremely rare compared with abscess and pachymeningitis. Histopathologic examination remains the mainstay of definitive diagnosis, as culture may be negative in significant number of cases. Aggressive surgical excision with prolonged antibiotic therapy enhances the chances of a good functional outcome.