It Can't Be Me, But … Maybe it's Both of Us?

A 53-year-old male chef with extensive travel for work, history of T2DM (A1c 6.8%) developed positional headaches and diplopia over one month. Exam showed absent abduction of the left eye. MRI without gadolinium showed an infiltrative left petroclival lesion extending into the cavernous sinus. Endoscopic biopsy showed inflammatory infiltrates and he was treated for a sinus infection. Headaches worsened one week later. Infectious workup, including repeat endoscopic biopsy, showed no active infection but elevated serum IgG4. He was discharged on a steroid taper for suspected inflammatory/infiltrative process. He returned one month later with worsening headaches, left facial weakness and hearing loss. MRI showed increased soft tissue fullness around the left cerebellopontine angle extending into the left pons and midbrain. He had an episode of emesis and sudden lethargy. CT head showed acute hydrocephalus; an EVD was placed and converted to a shunt. He received 5 days of IV steroids for suspected IgG4-RD. Brain biopsy performed showed a dense population of histiocytes and non-caseating granulomas. Pathology sent to an outside institution confirmed non-necrotizing granulomatous inflammation including well-formed giant cells. Auramine stain highlighted rare mycobacterium. He was started on RIPE + azithromycin for suspected mycobacterial infection. Extensive workup, including LPs, serial imaging and serum studies revealed no alternative etiology. Samples were sent to two outside institutions for metagenomic next generation sequencing (mNGS). At follow-up outpatient visit, he was found to have new dysarthria, left facial numbness, left eye supraduction deficit with new vertical diplopia, persistent hiccupping and gait imbalance. He was readmitted and MRI showed interval enlargement of heterogeneous multifocal cystic enhancing lesions centered in the left petrous apex with extension into the cerebellopontine angle, pons and cerebellar peduncle. Lethargy progressed, ultimately requiring intubation. Cerebellar biopsy showed friable, inflamed tissue. Despite aggressive broad treatment with antimicrobials, antiparasitics and antifungals, patient ultimately died.