Neuroendocrine carcinomas (NECs) of the colon are among the rarest types of colorectal cancers. Among these, large cell type neuroendocrine carcinoma (LCNEC) is particularly rare. Colorectal NEC is an aggressive disease, and there are few reports of long-term survivors. Here, we report a case of LCNEC accompanied by disseminated peritoneal leiomyomatosis that was difficult to diagnose. The case involves a 62-year-old female found to be positive for fecal occult blood by medical examination. An endoscopy revealed a tumor in the ascending colon, and the biopsy revealed poorly differentiated cancer. Abnormal FDG accumulation with peritoneal thickening was visible on 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET) and suspected to be peritoneal dissemination. Laparoscopic ileocecal resection was performed for the tumor of the ascending colon with abdominal wall invasion. At that time, numerous intra-abdominal nodules were observed, indicating peritoneal dissemination. The pathological diagnosis of the primary lesion was LCNEC, and the patient requested to undergo total peritoneal resection. After one course of chemotherapy with irinotecan plus cisplatin, she underwent total peritoneal resection, uterine annex resection, left inguinal lymph node resection, and intra-abdominal hyperthermic intraperitoneal chemotherapy with mitomycin C. Because a postoperative pathological examination revealed that the intra-abdominal nodules were leiomyomas, we diagnosed the patient with disseminated peritoneal leiomyomatosis. The left inguinal lymph node was diagnosed with a metastatic tumor. In summary, the final diagnosis was LCNEC in the ascending colon with inguinal lymph node metastasis. Postoperative chemotherapy has been administered to date. She is currently 18 months post-primary surgery and 15 months post-peritonectomy without apparent recurrence or metastatic findings. We experienced a case of Stage IVa colorectal LCNEC accompanied by disseminated peritoneal leiomyomatosis. Although the prognosis is generally poor, multidisciplinary treatment for advanced colorectal LCNEC may result in a favorable outcome for some patients. If peritoneal dissemination is suspected during operation, sampling of the nodule to confirm the pathological diagnosis is advisable.

Neuroendocrine tumors (NETs) are a heterogeneous group of tumors. NET of colon represent less than 1% of colonic tumors. Synchronous liver metastases, present in 75-80%, are considered significant adverse prognostic indicators. Liver is the second commonest site for metastasis in patients with colorectal neuroendocrine tumors. Available treatment options include surgical resection, chemotherapy, biotherapy. Surgery is the gold standard for curative therapy and it is strictly related to the localization, the grade of tumor, and the stage of disease. We present a 64-year-old man with clinical carcinoid syndrome. Colonoscopy revealed ileocecal valve vegetating mass with negative biopsy. CT scans of thorax and abdomen showed a voluminous lesion (10 cm of diameter) of right liver. CEA, CA 19.9 and aFP were all normal. Only urinary 5HIAASerum 5-hydroxyindoleactic acid and blood Chromogranin A were positive. Surgical strategy was to treat the primary tumor and the liver synchronous metastasis in one stage surgery. Management of NETs liver metastases is challenging and requires aggressive therapy. Currently, there are many therapeutic options for metastatic NETs. Although complete surgical resection remains the optimal therapy and aggressive surgical resection increases the 5-year survival of NETs with solitary liver metastasis to 100%. In this case, clinical status with doubt of carcinoid syndrome was essential for diagnosis and for subsequent surgical strategy with one stage surgery. Resection of the primary tumor, liver metastases, and local mesenteric lymph node metastases is thought to strictly promote long-term survival and quality of life. Typically, a multidisciplinary approach is a cornerstone for decision making while dealing with this aggressive disease. Carcinoid syndrome, Liver surgery, NETs, Neuroendocrine tumor, One stage surgery, Synchronous liver metastasis. I tumori neuroendocrini (NETs) rappresentano un gruppo eterogeneo di neoplasie. I NET del colon costituiscono meno dell’1% dei casi di neoplasie coliche. Le metastasi epatiche sincrone, presenti nel 75-80% dei casi, sono considerate un indice prognostico sfavorevole. Le opzioni terapeutiche disponibili includono la resezione chirurgica, la chemioterapia, e la bioterapia. La chirurgia rappresenta il gold standard della terapia curativa ed è fortemente condizionata dalla localizzazione, il grading e la stadiazione della neoplasia. Il caso clinico preso in oggetto è un uomo di 64 anni che presentava la sindrome da carcinoide. La colonscopia rilevò una massa vegetante della valvola ileocecale con biopsia negativa. La TC stadiativa mostrò una voluminosa lesione del fegato di destra con un diametro massimo di 10 cm. I markers tumorali erano negativi; mentre risultarono positivi i dosaggi urinari dell’acido 5-idrossiindolacetico e i valori plasmatici della Cromogranina A. Il trattamento chirurgico prevedeva l’asportazione del tumore primitivo e della sincrona metastasi epatica in un unico tempo chirurgico. Il management delle metastasi epatiche dei NETs resta controverso e richiede una strategia terapeutica multidisciplinare aggressiva. Al momento, molte sono le opzioni terapeutiche proposte, sebbene la completa resezione chirurgica della neoplasia resta la terapia di scelta poiché associata ad un aumento della sopravvivenza a 5 anni del 100% nei pazienti con singola metastasi epatica. La resezione del tumore primitivo con associata linfadenectomia e delle metastasi epatiche, in un unico tempo operatorio come presentato nel nostro caso, è fortemente indicato poiché migliora la qualità di vita e la sopravvivenza in questi pazienti.