Primary small-cell neuroendocrine carcinoma of the bladder: a very rare histological subtype
Siham Mesmoudi, Ali Mohammed Miko, Salma bencheikh, Taha Yassine Aaboudech, Sabrine Derqaoui, Ahmed Jahid, Zakiya Bernoussi, Ayoub Bouhnib, Saad Mesbahi, Ahmed Ibrahimi, Kaoutar ZnatiAbstract
Primary small cell neuroendocrine carcinoma (SCNC) of the bladder is an exceptionally aggressive malignancy. We report the case of an 80-year-old male, a chronic smoker, presenting with an 8-month history of intermittent total hematuria. Cystoscopy revealed a 72 mm mass infiltrating the bladder dome, posterior, and lateral walls. Histopathological analysis of transurethral resection specimens demonstrated a necrotic diffuse proliferation of monomorphic small cells infiltrating the muscularis propria. Immunohistochemistry showed positivity for synaptophysin, chromogranin A, CD56, and TTF1, whereas GATA3 and p63 were negative. The Ki-67 index exceeded 90%. Systemic staging (cT3bN0M0) confirmed the primary bladder origin. Although multimodal management, including neoadjuvant chemotherapy and radical cystoprostatectomy, was recommended, the patient-initiated chemotherapy but declined surgery. Primary bladder SCNC is a highly invasive entity requiring early diagnosis and multidisciplinary care. The diagnosis is strictly anatomopathological. Differentiating this entity from primary pulmonary small cell carcinoma is a critical challenge, making systemic radiological staging mandatory.