Solitary Aggregatibacter aphrophilus tectal abscess in an immunocompetent patient

A solitary abscess involving the tectum, specifically by Aggregatibacter aphrophilus, is an extremely rare condition with no known reported cases to date.

Here, we present a case of isolated solitary midbrain tectum abscess in an immunocompetent 28-year-old male who was empirically diagnosed as a primary tectal tumor at an outside hospital where he also underwent placement of a ventriculoperitoneal shunt (VPS) for obstructive hydrocephalus. Eight weeks later he was readmitted with a VPS infection. He was transferred to our institution where the VPS was removed and he was started on broad-spectrum antibiotics. Cerebrospinal fluid (CSF) culture revealed A. aphrophilus. All other workup was negative for infectious etiologies. The tectal lesion completely resolved after 15 weeks of intravenous ceftriaxone without surgical aspiration.

We suggest that an empiric diagnosis of tectal glioma should be made with caution for a ring-enhancing mass. CSF should be routinely cultured at the time of operative diversion if abscess is a possibility.