Rectal mixed adenoneuroendocrine carcinoma: Case report

RATIONALE: Colorectal mixed neuroendocrine–nonneuroendocrine neoplasms constitute a rare group of gastrointestinal tumors composed by both neuroendocrine and nonneuroendocrine components. Nondiagnostic macroscopic features, specific histological features, and poor awareness of the disease are responsible for the underestimated incidence and conflicting data available. Due to lack of randomized clinical trials and validated clinical guidelines, diagnostic and therapeutic approach are based on the standard of care for pure colorectal neuroendocrine carcinomas or adenocarcinomas. PATIENT CONCERNS: A 76-year-old caucasian male, without relevant medical or familial history, presented a positive faecal occult blood test during colorectal cancer screening. DIAGNOSIS: Total colonoscopy identified a rectal lesion with biopsy showing a moderate rectal adenocarcinoma staged as cT2N0M0. INTERVENTIONS: Anterior resection of the rectum with right ileostomy followed by local radiotherapy with radio-sensitising chemotherapy and adjuvant chemotherapy with capecitabine 1000 mg bid plus oxaliplatin 130 mg/m(2). Due to chronic nodular pulmonary aspergillosis and chemotherapy induced immunosuppression patient was on 400 mg/daily of oral voriconazole. OUTCOMES: Overall survival of 15 months after progression under first line treatment and under palliative chemotherapy with platinum plus etoposide regimen. LESSONS: The reported case illustrates the challenge associated to the management of mixed neuroendocrine–nonneuroendocrine carcinomas due to lack of validated guidelines and scientific evidence. From diagnosis and staging to treatment, all steps must be tailored to individual clinical and histological features.