ABSTRACT
Type 1 neurofibromatosis (NF1) is a common genetic disease that increases a patient’s lifetime risk for malignancy. Multiple myeloma (MM) is one malignancy that is associated with the disease less frequently and like other tumours, may be more aggressive as well as have unusual presentations. Therefore, MM must be considered as a differential diagnosis in any NF1 patient presenting with an extremity tumour. The aggressive nature can be assessed with haemoglobin concentration and specific tumour markers. The poor prognostic features of tumours in NF1 patients are often present and should be looked for in assessing this cohort.