lymphangiomas are rare benign tumors that are preferentially located in the head and neck in children ( 1 ) .
lymphangiomas in the peritoneal cavity are extremely rare occurring most commonly in the mesentery , followed by the omentum , mesocolon , and retroperitoneum .
the etiology is unclear , but they are considered primarily to congenital in origin ( 2 ) .
we report the case of a young woman with appendicular pain caused by a cystic lymphangioma of the right iliac fossa : a rare but possible differential diagnosis .
a 17-year - old female patient presented with a dull abdominal pain in the right iliac fossa and flank of a 1-month duration .
an abdominal examination revealed hyperactive bowel sounds and tenderness during palpation in the central abdominal quadrant and right iliac fossa in mc burney point .
neoplastic markers ( afp , cea , ca 19 - 9 , ca 15 - 3 , ca125 , tps ) were negative .
axial and coronal t2-weighted tse images showed the presence of a fluid - filled cystic lesion in the retrocaecl adipose tissue .
an ultrasonographic and ct scan of the abdomen revealed the presence of a cystic mass ( max diameter 60 mm ) in the retrocaecal adipose tissue that was in proximity of the caecum , appendix and ileum .
in addition , the ct scan revealed the presence of multiple hypodense formations in the body and tail of pancreas . during the hospital
the exam revealed in the retrocaecl adipose tissue the presence of a fluid - filled formation with a diameter of 60 mm that appeared indissociable from the caecum for the presence of a tissue connection ( fig 1 ) .
other cystic lesions ( communicating with pancreatic duct ) were present in the whole pancreas and in the right kidney .
fluid - filled cystic lymphangioma with polycyclic edge and internal septa ( intraoperative specimen ) the patient underwent exploratory surgery : at laparotomy a yellowish oval formation with a diameter of 6 cm was found arising from the mesentery of terminal ileum with partial adhesion of the appendix .
the lesion had a cystic aspect and was fluid - filled ( fig 2 ) .
the patient has been followed - up for two years with semestral clinical examination and abdominal eco scan and no recurrence occurred .
intra - abdominal mesenteric lymphangioma is an uncommon tumor that usually manifestes in early adulthood .
this tumor has an incidence of approximately 1/20,000 and 1/250,000 hospital admissions , and it is more frequent in men than women with a m / f ratio of 3:1 ( 3 ) . in intraperitoneal sites , the small bowel mesentery ( 70% )
is the commonest localization , with 5060% of all cysts located in the ileal mesentery .
( 4 ) the etiology of mesenteric lymphangioma is considered to be congenital , with abnormal embryonic development of the lymphatic system causing sequestration of lymphatic tissue ( 1 ) : infact in our patient also other cystic lesions ( kidney and pancreas ) were found at abdomen ct / mri .
radiological investigations are a useful diagnostic tool , but definitive diagnosis is confirmed by histopathology after a complete surgical resection .
( 5 ) at immunochemistry : the lining mesothelial cells are immunoreactive for cytokeratin and negative for factor viiiis .
double staining with prox1 and cd31 is the most reliable method for characterizing lymphangioma endothelial cells.(6 )
 pain of the right iliac fossa in young girls can relate to several pathologies of the gastrointestinal and genitor - urinary tract . on the other hand , lymphangiomas in the peritoneal cavity are extremely rare . 
 we report the case of a young woman with pain in the right iliac fossa caused by a cystic lymphangioma . a 17-year - old caucasian female patient presented with abdominal pain in the right iliac fossa and flank of a 1-month duration . 
 the patient was apyrexic and laboratory tests were negative . 
 ct / mri of abdomen showed a cystic mass ( max diameter 60 mm ) in the retrocaecl adipose tissue in connection with the caecum and appendix . 
 the patient underwent a total excision of the lesion and appendicectomy . 
 histopathological examination was consistent with the diagnosis of mesenteric lymphangioma . 
 this case shows a rare but possible cause of right iliac fossa pain in young women to be considered in the differential diagnosis . 
INTRODUCTION
CASE REPORT
DISCUSSION