cystic lesions of the pancreas occasionally present problems in diagnosis and management , especially when found incidentally .
cystic lesions can be broadly classified as follows : congenital true cyst ; primary cystic neoplasms ; acquired cysts , including parasitic cysts and postinflammatory cysts ( pseudocyst , retention cyst ) ; extra - pancreatic cystic disorders masquerading as pancreatic cyst ; and other miscellaneaus cystic lesion .
endometriosis is defined as the presence of endometrial glands and stroma occurring outside of the uterine cavity .
it has been encountered in multiple sites such as the ovaries , fallopian tubes , uterus , peritonium , uterine ligaments , rectovaginal septum , cervix , vagina , vulva , skin , umbilicus , incisional scars , hernia scars , bladder wall , kidney , pelvic lymph nodes , extremities , lung , pleura , large intestine , rectum , appendix , gallbladder , stomach , and spleen .
we report a patient with a cyst in the body of the pancreas that on pathologic examination proved to be lined by the ectopic endometrial tissue .
a 21-yr - old korean woman was admitted to the hospital with a recurrent epigastric pain and 8 kg weight loss over a one year period .
she denied a history of hepato - biliary disease , alcoholism , previous surgery , traumatic abdominal injury or cyclic abdominal pain .
her menstrual history was normal . on admission , her blood pressure was 120/80 mmhg , pulse 80/min , temperature 36.5c and respirations 20/min . on examination , there was no abnormally palpable mass in her abdomen .
laboratory data on admission was as follows : hemoglobin 12.4 g / dl , hematocrit 37.3% , white blood cell count 5,500/mm , platelet 300,000/mm , total protein 6.4 g / dl , albumin 4.2 g / dl , total bilirubin 0.7 mg / dl , ast 10
iu / l , alt 9 iu / l , alklaine phosphatase 135 iu / l , ggt 12 iu / l , amylase 60 u , cea 1.24 ng / dl , ca-125 8.71 u / ml , ca 19 - 9 54.34 u / ml , afp 0.4 ng / ml , ca 15 - 3 9.09 u / ml .
computed tomography of the abdomen showed a 3.54.0 cm - sized , oval - shaped low density cystic mass involving the body of the pancreas with bulging - out contour .
there was no definite pancreatic duct dilatation ( figure 1 ) . with a preoperative diagnosis of mucous cystic adenoma , the patient underwent partial pancreatectomy .
gross finding of surgical specimen revealed a 4.04.04.5 cm well - circumscribed cyst located within the pancreatic stroma .
the cyst was lined by a smooth , trabeculated , grey - brown wall with focal areas of hemorrhage .
on microscopy , the cyst was covered with fibrous tissue containing endometrial elongated glands consisting of cuboidal and columnar cells with basal nuclei and amphophilic cytoplasm .
the glands were admixed with well - vascularized spindle cell stroma containing multiple areas of focal hemorrhage and hemosiderin deposition in macrophage ( figure 2 ) .
immunohistochemical examinations showed positive tests to antibodies to the estrogen receptor - related protein ( er ) and the nuclear progesteron receptor protein ( pr ) ( figure 3 ) .
extrapelvic endometriosis refers to endometropic implants found in other areas of the body , including the vagina , vulva , cervix and perineum , in the inguinal canal , the urinary system , the gastrointestinal tracts , pulmonary structures , extremities , skin and central nervous system .
the epidemiology , diagnosis and natural history of extrapelvic endometriosis appear to differ somewhat from endometriosis .
it remains uncertain whether lesions distant from pelvic sites even represent the same disease process and whether the same diagnostic and treatment modalities are appropriate .
the intestines are involved in 515% of all the cases of endometriosis , and the gastrointestinal tract is the most common site of extrapelvic disease .
cystic endoteriosis of the pancreas is very rare and has been mentioned in the literature only four times .
but , in our presented case , an endometrial cyst was located in the body of the pancreas .
endometriosis is defined as the presence of endometrial glands and stroma occurring outside of the uterine cavity .
histopathological demonstration of endometrial tissue from various parts of the mass is desirable for confirmation of the diagnosis . in our presented case ,
immunohistochemical investigations of a previous report with antibodies to the estrogen receptor - related - protein and the nuclear progeteron receptor protein was negative . in our case however , immunostaining were positive .
the possible pathogenesis of endometriosis in multiple organs has been the subject of controversy and numerous theories . for more than 70 years
interest in the genesis of the endometric lesion has been a focus since the earliest studies .
the theory of direct extension proposes that endometriosis results from direct invasion of the ectopic endometrium through the uterine musculature .
spread of endometrial glands and stroma through muscle fibers or along lymphatic and venous channels may , in fact , be a progenitor of adenomyosis , but the relationship of direct endometrial spread to endometriotic implants is not well established .
the theory of coelomic metaplasia holds that endometriosis developed from metaplasia of cells lining the pelvic peritonium .
this is based on embryologic studies demonstrating that mullerian ducts , germinal epithelium of the ovary and pelvic peritoneum are all derived from the same embryologic precusor .
an attractive component of the coelomic metaplasia theory is that it can account for the occurrence of endometriosis anywhere in the abdominal cavity .
the theory of lymphatic and vascular metastasis had esuggested that endometriosis could result from lymphatic and hematogenous dissemination of endometrial cells .
it has been offered as an explanation for rare cases of endometriosis occurring in locations remote from the peritoneal cavity .
in addition to pleural tissue , endometriosis has been reported in pulmonary parenchyma , bone , biceps muscle , peripheral nerves and the brain . the composite theory of the histogenesis of endometriosis combines the implantation , vascular / lymphatic metastasis and direct extension theories . in a previous report , the pancreas was located in the retroperitoneum and had no clear connection with the peritoneal cavity , a finding that endometrial fragments could be transported through lymphatic or blood vessels into such distant sites . because there are protean manifestations of endometriosis , it is likely that several mechanisms are involved in the pathogenesis .
further clinical and experimental investigations are needed to evaluate the pathogenesis of endometriosis occurring in unusual sites .
 pancreatic endometrial cyst is an extremely rare instance of ectopic endometriosis that was first described by marchevsky in 19841 ) . 
 a 21-yr - old woman with a history of epigastric pain and weight loss was found to have a cystic lesion in the pancreas on ct - scan . under the tentative diagnosis of a pancreatic cystic neoplasm 
 , partial pancreatectomy was performed . 
 histopathological examination of the specimen revealed cystic endometriosis . 
 the clinicopathological features of the lesion are discussed and literature concerning this extremely rare lesion is reviewed . 
INTRODUCTION
CASE REPORT
DISCUSSION