Refractory Pruritus in End-Stage Prostatic Adenocarcinoma: An Unusual Presentation of A Hypereosinophilic Syndrome.

INTRODUCTION: Hypereosinophilic syndrome (HES) associated with advanced adenocarcinoma of the prostate is an exceptionally rare paraneoplastic condition. Available evidence suggests that eosinophilia may correlate with tumour progression and poor prognosis. Cutaneous manifestations, including severe pruritus and angioedaema, may significantly impair quality of life and represent particularly challenging symptoms in a palliative care setting. Pruritus management requires individualised multidisciplinary approaches including corticosteroids, antihistamines, gabapentinoids, antidepressants, opioid modulation and supportive care measures. In refractory cases, severe pruritus associated with HES may become a source of profound suffering and in end-of-life care may require palliative sedation to relieve otherwise intolerable distress. CASE DESCRIPTION: We report the case of a patient with prostatic acinar adenocarcinoma who developed paraneoplastic HES, presenting with severe refractory pruritus and recurrent angioedaema. Despite multiple symptomatic treatments, the patient experienced progressive symptom burden with significant impairment in quality of life, ultimately requiring terminal palliative sedation during end-of-life care. CONCLUSION: This case highlights the diagnostic challenges of HES, the importance of malignancy progression and the severe impact of uncontrolled eosinophil-mediated symptoms in advanced cancer. LEARNING POINTS: Paraneoplastic hypereosinophilic syndrome should be considered in patients with advanced prostate adenocarcinoma and persistent unexplained eosinophilia after exclusion of allergic, infectious, autoimmune, endocrine and haematologic causes.In paraneoplastic hypereosinophilic syndrome, the severity of pruritus may not correlate with peripheral eosinophil counts, and symptom burden can persist despite corticosteroid therapy and normalisation of eosinophilia.To our knowledge, this is one of the first reported cases of paraneoplastic hypereosinophilic syndrome secondary to metastatic prostate adenocarcinoma in which refractory pruritus became the indication for palliative sedation.