Abstract We present three patients who developed distinct cutaneous manifestations of thymoma: a rare mediastinal tumour. A 25-year-old man was treated for myasthenic crisis. Past medical history included thymectomy in 2016. Admission imaging confirmed recurrence thymoma. He red–brown macular rash affecting the trunk, back and thighs. Biopsy showed florid lichenoid dermatitis consistent with gr...