Background: Brainstem abscess is a rare condition with a variety of treatment approaches. In this paper, we report an unusual case of a brainstem abscess with a positive outcome in an immunocompetent patient who was treated with antibiotic therapy. Case Description: A 22-year-old female presented with bilateral tetraparesis that was worse on the left hemibody, appendicular tremor, and left upper eyelid ptosis. Brain magnetic resonance imaging showed an abscess in the pons and midbrain due to possible nocardiosis. She was treated with dexamethasone, phenytoin, vancomycin, and meropenem for 8 weeks and trimethoprim-sulfamethoxazole for 6 weeks. The brain injury decreased, and the patient’s neurological status significantly improved. Conclusion: Brainstem abscess may be treated conservatively, leading to improvement of the clinical condition and decreased lesion size on imaging.