Abstract
INTRODUCTION: Prostatic large-cell neuroendocrine carcinoma is poorly studied. Although several case reports are available, information on the clinicopathological characteristics of this disease is limited, particularly for the de novo (hormone-naive) type. Herein, we report an extremely rare de novo case of this disease with a good prognosis despite a multi-metastatic status. CASE PRESENTATION: An 83-year-old male patient presented with a high serum prostate-specific antigen level and was found to have de novo prostatic large-cell neuroendocrine carcinoma with an adenocarcinoma component upon pathological examination. Diagnosed with stage pT4cN1cM1c, he underwent chemo-hormonal therapy using a luteinizing hormone-releasing hormone antagonist and combined etoposide and cisplatin, which achieved a partial response. The patient has survived for 20 months without progression. CONCLUSION: Although prostatic large-cell neuroendocrine carcinoma is known for its aggressive clinical behavior, the de novo type with an adenocarcinoma component may be sensitive to hormonal therapy and achieve a good prognosis.