A paraneoplastic manifestation of metastatic breast cancer responding to endocrine therapy: a case report

BACKGROUND: Many cancers are known to be associated with paraneoplastic syndromes. These syndromes are usually treated by chemotherapy with or without immunosupression but they often respond poorly. There are no published reviews on response to endocrine treatment. CASE PRESENTATION: We report a case of a patient presenting with papillitis, myositis and sensory peripheral neuropathy 18 months before a diagnosis of metastatic oestrogen receptor positive breast cancer was confirmed. The patient was treated with anastrozole which led not only to a decrease of her tumour burden but also to an improvement in her biochemical markers and amelioration of her clinical symptoms. CONCLUSION: This case is an example of breast cancer presenting with paraneoplastic manifestations. It took several months to establish the cause of symptoms in this patient thus illustrating the need for physicians to maintain a high index of suspicion for paraneoplastic syndromes in women presenting with unusual neurological symptoms with no obvious cause. It is a unique case as it illustrates how treatment with an aromatase inhibitor leading to cancer regression can result in an improvement in the paraneoplastic symptoms.