Primary hepatic carcinoid tumor

Guillermo Peralta, MD, Gabriela Arredondo, Medical, Student, Eduardo Flores, MD, Zanndor del Real-Romo, Cesar Jaurrieta, Carlos Rodriguez-Montalvo. Instituto Tecnologico de Estudios Superiores de Monterrey

Neuroendocrine tumors are neoplasms that originate from the cells of the neuroendocrine system; depending on the site of origin, hormonal production and differentiation can present an extensive clinical behavior; the clinical manifestations include episodic flushing, wheezing, diarrhea, abdominal pain, and eventual right-sided heart failure.

These tumors can be found in a range of organs; most of them, nearly 90%, occur within the gastrointestinal tract, the most common sites of primary disease are the appendix (35%), small intestine (25%) and rectum (12%). Metastases from these tumours frequently involve the liver. Primary hepatic carcinoid tumors are extremely rare, and their origin is not well known, there are several theories which include that chronic inflamation in the biliary system may initiate intestinal metaplasia, another possible explanation is that they originate from ectopic pancreatic or adrenal tissues found within the liver.

A 63-year-old woman was hospitalized with a history of intermittent diarrhea of about a year of evolution, associated to weight loss of 8 kg during the same period. An ultrasonogram showed an 8 x 7.5cm complex cystic mass in the right hepatic lobe. MRI and CT SCAN findings were compatible with hydatid tumor vs hemangioma. Tumor markers and liver enzymes were within normal limits. Right hepatectomy was performed without complications. Microscopic findings revealed a carcinoid tumor. Postoperatively a PET SCAN was achieved without showing any other primary tumors.

A diagnosis of a hepatic carcinoid is far more likely to be a metastasis from the gastrointestinal tract than a true primary. Nonetheless, primary hepatic carcinoids need to be differentiated from metastatic lesions to institute appropriate treatment. Clinically, primary lesions are characterized, in most cases, by the absence of an overt endocrine syndrome. Liver carcinoid tumors are usually solitary.

The diagnosis of hepatic primary carcinoid is rarely suspected preoperatively. Ultrasound, computed tomography, MRI and angiography findings are sometimes useful in distinguishing carcinoid from other tumours. CT with intravenous contrast and MRI with gadolinium often show tumour enhancement, highlighting tumour hypervascularity.

The diagnosis of hepatic carcinoid tumor is mainly based on histological and immunohistochemistry examination.The differentiation between primary and secondary hepatic carcinoid tumor it cannot be made by histology alone; it involves intensive imaging, and follow up.

Surgical resection is the preferred treatment for PHCT and has provided favorable outcomes. One study showed that postoperative 1-, 5-, and 10-year survival rates were 88%, 80% and 68%, respectively. As far as we know, this is the first case of primary liver carcinoid tumor reported in our country.