Hypertrophic olivary degeneration in a patient with lung cancer

A 78-year-old woman developed a coarse tremor in her left hand that had persisted for 2 months. 3 years before, she had undergone surgery for lung adenocarcinoma, followed by chemotherapy. On examination, there was a postural and action tremor (3-4 Hz) in the left upper limb, identified as a Holmes tremor, with oculopalatal myoclonus. MR scan of the brain showed bilateral hypertrophic olivary degeneration with hyperintensity of the middle cerebellar peduncles. CT scan of the head showed a calcified lesion in the pontine tegmentum, suggesting disruption of the Guillain-Mollaret triangle, which comprises the dentatorubral, rubro-olivary and olivocerebellar pathways. The underlying cause was a pontine metastasis, evidenced by calcification on CT brain scan. This case highlights the importance of considering underlying malignancy in people with hypertrophic olivary degeneration or related symptoms and emphasises the role of CT brain scanning in identifying metastatic calcification when MR scan findings are inconclusive.