Actinomycosis masquerading as malignancy.

We describe a patient who presented with neurological symptoms and radiological findings consistent with metastatic malignancy in several sites. However, no obvious primary site of tumour was identified and the patient later went on to develop clinical features of sepsis whilst using palliative dexamethasone therapy. A diagnosis of actinomycosis was eventually made on open lung biopsy and the patient recovered completely on penicillin V. This case serves to illustrate the need to obtain a formal tissue diagnosis whenever possible in all cases of suspected malignancy, in addition to exposing the weaknesses inherent in empiric diagnoses.