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A 50-year-old woman presented with a short history of headaches and dizziness. One week earlier she noticed impaired right leg coordination and had fallen twice. She had no significant past medical history. Examination showed impaired right arm and leg coordination, mild pronator drift and gait ataxia with no other neurological deficits. A magnetic resonance imaging scan of the brain showed an intra-axial mass lesion centred on the right middle cerebellar peduncle with partial effacement of the fourth ventricle and an unusual, slightly nodular pattern of enhancement (Figure 1). A computed tomography scan of the chest demonstrated bilateral nodular hilar masses felt consistent with reactive lymphadenopathy. No single large mass was present. Brain magnetic resonance imaging was consistent with either a primary lesion or atypical metastasis. She commenced dexamethasone 4 mg four times per day and stereotactic biopsy was scheduled. The planning magnetic resonance imaging, 2 weeks later, demonstrated marked reduction in the lesion's size raising the possibility of CNS lymphoma. Surgery was cancelled. Lumbar puncture showed no abnormalities. The steroid dose was reduced as a result of cushingoid sequelae and to establish if the lesion would re-expand. Interval scans showed progressive reduction in mass size despite decreasing steroid doses. Partial signal normalization within the cerebellum with resolution of mass effect and enhancement was observed (Figure 2). Repeat computed tomography of the chest (Figure 3) showed new, small, peripheral, left and right upper lobe pulmonary lesions. Histology following open biopsy of the left-sided lesion showed noncoalescent non-necrotizing granulomata consistent with sarcoidosis. Six months later the patient remains symptom free on prednisolone 2.5 mg once per day.