Spontaneous rupture of hepatic metastasis from small cell neuroendocrine carcinoma of maxillary sinus

Background Small cell neuroendocrine carcinoma of the maxillary sinus, a rare malignant tumor, has a poor prognosis because of its high incidence of metastasis. Moreover, metastatic cancer-induced hepatic rupture, characterized by hemoperitoneum, is infrequent, although several lines of evidences have reported that a wide variety of other neoplasms can cause this usually fatal manifestation. Case presentation We now present the first case of a 49-year-old man with spontaneous rupture of hepatic metastasis from small cell neuroendocrine carcinoma of the maxillary sinus and ultimately resulted in massive intraperitoneal bleeding, which was successfully controlled by subsequent surgery (partial hepatectomy). The postoperative clinical manifestation of the patient was uneventful. He was discharged on the 16th day after operation and without any complication. Conclusions Small cell neuroendocrine carcinoma of the maxillary sinus is very scarce and unfortunately has a poor prognosis. It has potential to cause spontaneous metastatic rupture which can elicit fatal hemorrhage. Emergency surgery is effective, although the long-term outcome is still unsatisfactory.


Background
Small cell neuroendocrine carcinoma of maxillary sinus is a rare and aggressive malignant disease. Non-traumatic rupture of the liver frequently occurred in primary benign or malignant tumors, metastatic carcinoma, peliosishepatis, polyarteritisnodosa, systemic lupus erythematosus, and toxemia of pregnancy [1]. However, spontaneous hepatic rupture induced by metastatic cancer, which presented as hemoperitoneum, is not common [2]. We currently reported a patient with hemoperitoneum due to bleeding hepatic metastasis which was originated from small cell neuroendocrine carcinoma of the maxillary sinus, although there is no literature reporting it.

Case presentation
A 49-year-old man had undergone surgery to resect a small cell neuroendocrine carcinoma (SNEC) of the right upper maxillary sinus 21 months previously ( Figure 1). He underwent preoperative 'pingyangmycin'10 days of chemotherapy. The patient complained about persistent and severe right upper quadrant pain which lasted about 6 hours.
We observed that he had a pale complexion and distended, tender abdomen after careful physical examinations. The vital signs were a temperature of 36.8°C, blood pressure of 90/55 mmHg, and pulse rate of 130/min.
After fast-track resuscitation (4 units of packed red blood cells (600 mL) and 1,000 mL hetastarch 130/0.4 hydroxyethyl starch), the hemodynamics of the patient became relatively stable. Moreover, 2,500 mL of blood with clots were observed in the abdominal cavity in the operation. The liver tissue of the patient showed a normal color and a smooth surface in appearance, but there was an isolated lesion in segment 6 with a 6 cm laceration of the capsule, which skeptically was malignant tumor from macroscopical observation. There were no other observed bleeding sites. A resection of segment 6 of the liver was performed.

Discussion
Small cell neuroendocrine carcinoma of the sinonasal region is not common of the sinonasal carcinomas with neuroendocrine differentiation [3]. The histogenesis of the neuroendocrine differentiated tumors is not clear. It has been postulated that, outside the lung, this tumor is derived from the neuroendocrine amine precursor uptake decarboxylase (APUD) cells, which are widely distributed in the body. The tumors are composed of small-sized regular cells which are arranged in broad sheets, nests, and cords. Many of the cells contain cribriform nuclei with a fine reticular chromatin pattern and small to moderate amounts of cytoplasm [4]. Immunohistochemical observation is essential to make a pathological diagnosis. SNEC has been reported to stain strongly with synaptophysin and CD56 nerve cell adhesion molecule and weakly with chromogranin A and CAM 5.2/AE-1 [5]. The prognosis in cases of head and neck SNEC is very poor because of its high metastatic rate [6]. In this patient we reported, the tumor metastasized to the liver 21 months after maxillectomy.
The typical presentation is sudden epigastric or right hypochondria pain. Shock could be observed in some patients, while most patients were manifested with peritonitis or abdominal distension. Some patients are paracentesis-positive with blood-stained ascites. Ultrasonography, a simple, quick, non-invasive investigating method, can locate the ruptured tumor and reveal a free intraperitoneal blood collection. CT scan is invaluable for diagnosis and treatment planning because it can check the severity of the cirrhosis and locate the tumor.
Rupture of a hepatic metastasis frequently results in massive hemoperitoneum, which may be a terminal event [21]. For these patients, it is therefore crucial to control the bleeding and restore the blood pressure as soon as possible. Transcatheter hepatic arterial embolization (TAE) may seem to be ideal for these patients, since it avoids general anesthesia to stop the bleeding without operation [22], but it also has some demerits, including recurrent bleeding and liver failure [22,23], peritoneal abscess [24], and implanted metastases [25,26]. Furthermore, long-term results are poor if it is used as a sole treatment approach [27], and it is not applicable when the main trunk of the portal vein is obstructed. In addition, a two-stage surgical operation (that is, TAE followed by liver resection) would inevitably increase the hospital stay and the cost. For our patients, one-stage hepatectomy is still a good treatment method for those who are stable hemodynamically and has a reasonable liver function as well as the lesion is peripherally located.

Conclusions
Small cell neuroendocrine carcinoma of the maxillary sinus is very rare and has a poor prognosis. It may cause spontaneous metastatic rupture which resulted in fatal hemorrhage. Emergency surgery is effective but the outcome is still unsatisfactory.

Consent
Written informed consent was obtained from the patient's son for publication of this report and any accompanying images.