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obstruction of the appendiceal lumen with fecaliths or lymphoid hyperplasia is a well - known cause of appendicitis.1 in extremely rare cases , metastatic cancerous lesions of the appendix can cause appendicitis . we herein present a case of appendicitis derived from metastatic extrahepatic cholangiocellular carcinoma
an 87-year - old female was admitted to the department of medicine with a chief complaint of abdominal pain with jaundice .
she had a history of hypertension and type ii diabetes mellitus for which she was treated at the local clinic with regular medications .
laboratory findings revealed a white blood cell count within normal range ( 5,680 cells / mm with 74.7% segmented neutrophils ) , but c - reactive protein and the erythrocyte segmentation rate were elevated to 16.1 mg / l and 105 mm / hour , respectively .
liver function tests for aspirate aminotransferase , alanine aminotransferase , total bilirubin , direct bilirubin , alkaline phosphatase , and gamma - guanosinetriphospate were 284 iu / l , 403 iu / l , 9.1 mg / dl , 6.4 mg / dl , 540 iu / l , and 965 iu / l , respectively .
contrast - enhanced computed tomography ( ct ) revealed extrahepatic cholangiocellular carcinoma with direct hepatic invasion and lymph node metastasis in the para - aortic and peri - portal area .
in addition , a dilated appendiceal lumen caused by a soft tissue mass at the base of the appendix was detected ( fig .
1 ) . positron emission tomography - computed tomography ( pet - ct ) scan revealed an approximately 4.3 cm hypermetabolic mass in segment 4 of the liver with biliary dilatation and hypermetabolic nodes in the portocaval and para - aortic areas .
the patient underwent an endoscopic retrograde cholangiopancreatography ( ercp)-guided biopsy of the common bile duct ( cbd ) and ultrasonography - guided biopsy of the metastatic hepatic mass .
the result of the hepatic mass revealed adenocarcinoma ; however , the results of the cbd revealed chronic non - specific inflammation .
although the rebound tenderness was not severe , we were concerned that the degree of appendicitis might intensify as the metastatic mass in the appendix grew .
therefore , we decided to perform an elective laparoscopic appendectomy before the start of palliative chemotherapy .
a mass - like lesion was detected between the proximal appendix and the cecum base ( fig .
the pathologic report indicated metastatic adenocarcinoma involving the subserosa and proper appendiceal muscle involving the serosa through the mucosa of the cecum ( fig .
immunohistochemical staining revealed positive expression of cytokeratin 7 ( ck7 ) but negative expression of cytokeratin 20 ( ck20 ) and cdx 2 in tumor cells , which was suggestive of adenocarcinoma of upper gastrointestinal or pancreaticobiliary origin ( fig .
she later underwent a self - expandable metallic stent insertion in the biliary tract to relieve bile duct obstruction ; however , she refused to undergo palliative chemotherapy .
follow - up ct after three months of laparoscopic appendectomy revealed more progressive disease with peritoneal carcinomatosis .
luminal obstruction of the appendix caused by fecaliths or lymphoid hyperplasia is a major cause of appendicitis .
unusual factors such as parasites , endometriosis , bacteria , and primary and metastatic tumors can also cause appendicitis in rare cases.1 primary appendiceal cancer is rare and is found in only 0.9 - 1.4% of all appendectomy specimens .
in addition , metastatic appendiceal cancer is much more rare.2,3 in a recent literature review , only seven patients were found to have metastatic appendiceal cancer among 80,698 patients.1 the primary sites of metastatic appendiceal carcinomas were the lung , breast , cervix , prostate , stomach , liver , nasopharynx , mediastinum , and pancreas.3,4,5,6,7,8,9,10,11,12,13 as far as we know , primary cholangiocellular carcinoma very rarely metastasizes to the appendix.14 without imaging studies for patients with suspected appendicitis , it is very difficult to diagnose primary or metastatic carcinoma of the appendix.2,6,7,8,9,10,11 as imaging modalities are more frequently used , appendiceal masses are found before surgery more commonly , sometimes with unusual characteristics.3,4,5,13 in a recent report of a case of appendiceal metastasis from a hepatocellular carcinoma , ct scan was useful in the diagnosis of the metastatic lesion .
it showed a hypervascular area on arterial phase and a hypo - dense area on delayed phase imaging , two imaging features that are similar to those observed in primary hepatocellular carcinoma.3 in our case , ct scan revealed an appendiceal mass with a dilated appendix and pet - ct revealed focal uptake of 18-fdg in the appendix base , which strongly suggested a malignant lesion .
although those examinations could not distinguish primary appendiceal carcinoma from a metastatic lesion of the appendix , they were helpful in the decision to perform an elective surgery .
it is known that cancer cells spread to other sites via the lymphatics , a hematogenous route , or direct invasion .
the common metastatic sites of cholangiocellular carcinomas are regional lymph nodes and adjacent organs ; distant metastasis is uncommon.15 in particular , appendiceal metastasis from cholangiocellular carcinoma is an extremely rare event . it has been suggested that metastatic appendiceal carcinoma usually begins as serosal implants , which encroach progressively on the lumen.6,7 in this case , the pathologic results revealed that metastatic adenocarcinoma was involved through the serosa to the mucosa of the cecum .
in addition , although there was no peritoneal seeding in the operative field , peritoneal carcinomatosis was confirmed by follow - up ct images three months after surgery .
thus , we think that serosal implantation with encroachment might be an adequate theory to explain the route of metastasis in the present case . in conclusion , although appendicitis caused by metastasis to the appendix from other primary cancer sites is extremely rare , physicians should be more cautious in recognizing the possibility when patients complain of right lower quadrant abdominal pain
. ct or pet - ct could be useful tools in detecting extraordinary appendicitis caused by metastatic extrahepatic cholangiocellular carcinoma .
metastatic carcinoma that causes appendicitis is extremely rare . to our knowledge , 
 metastatic cholangiocarcinoma in the appendix has been reported in only 1 case in the english literature . 
 we report herein the case of an 87-year - old woman who presented with abdominal pain and jaundice . 
 advanced cholangiocellular carcinoma and a proximal appendiceal mass with appendicitis were detected on contrast - enhanced computed tomography and positron emission tomography / computed tomography . after elective laparoscopic appendectomy and wedge resection of the cecum , pathologic results revealed metastatic adenocarcinoma from extrahepatic cholangiocellular carcinoma in the appendix .