{"paper_id":"a2427aba-2d77-4d63-ab92-aae35f1bbc69","body_text":"Endometriosis is defined as the presence of endometrial glandular tissue outside the\nuterine cavity. \n 1 \n  It is a common disease and can be seen in almost 5 to 10% of females in the\nreproductive age group. \n 2 \n  It is also seen in approximately 5% of postmenopausal females especially in\npatients on estrogen hormonal replacement therapy. \n 3 \n  Endometriosis has been linked with a genetic predisposition with findings of\nestrogen dependence and progesterone resistance. \n 2 \n  It is often associated with an inflammatory reaction and resultant fibrotic\nchanges at the site of the endometriotic deposits. \n 1\n\nA 31 years old female patient presented to the emergency department\ncomplaining of epigastric pain associated with nausea and vomiting. She has a past\nmedical history of recurrent episodes of acute pancreatitis and was treated\npreviously in another healthcare facility where no definitive aetiology was found.\nNo other significant past medical history was noted and no cyclical pattern of pain\nwas observed. No previous surgical history was disclosed nor family history of\npancreatic diseases or neoplasms was given.\nOn physical examination, the patients vital signs were normal. Chest was noted to be\nclear. Abdomen was soft except for mild tenderness in the epigastric region.\nLaboratory blood work-up showed elevated pancreatic enzymes indicative of\npancreatitis. The patient was admitted as a case of acute pancreatitis for further\ninvestigation and the treatment was initiated.\nA computed tomography (CT) scan of the abdomen and pelvis with IV contrast was done\ntwo days after admission and showed no sign of acute pancreatitis, no peripancreatic\nfatty striation or calcifications. However, a unilocular cystic lesion was seen at\nthe tail of the pancreas measuring approximately 3.6 × 3.3 cm in\ndiameter. Slight atrophy of the distal tail beyond the cyst was notable. No evidence\nof mesenteric or retroperitoneal lymphadenopathy was seen. Major vasculature\nappeared intact. ( Figure 1 )\nA. Axial non-enhanced CT section of the upper abdomen showing a cystic lesion\nat the tail of the pancreas. No wall calcifications appreciated. B&C\nAxial contrast-enhanced CT sections in arterial and porto-venous phases,\nrespectively, showing minimal wall enhancement of the pancreatic cyst with\nno internal solid component or septations.\nGadolinium-enhanced magnetic resonance imaging (MRI) of the abdomen was performed and\nthe results again showed a cystic lesion at the tail of the pancreas which appeared\nhypointense on T1 FATSAT in comparison with the pancreatic parenchyma and\nhyperintense on T2 HASTE sequences. There was no restriction of the cystic lesion on\ndiffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC). Minimal\ncontrast enhancement of the wall on post-contrast T1 FATSAT images was depicted. No\ngradient echo sequences were obtained. ( Figure\n2 )\nMRI axial sequences of the upper abdomen. A. T1 FATSAT showing a hypointense\ncystic lesion at the tail of the pancreas. B. T2 HASTE axial sequence\nshowing hyperintensity of the cyst. C.T1 FATSAT post-contrast imaging\nshowing only minimal enhancement of the cyst wall with no internal solid\ncomponent or septations. D&E. DWI and ADC showing no internal\nrestriction of the cystic lesion.\nThese findings on diagnostic imaging in addition to the patients history of recurrent\npancreatitis suggested a diagnosis of a pseudocyst as a complication of\npancreatitis. Nonetheless, a mucinous cystic neoplasm was also included as a\ndifferential diagnosis considering the location of the cyst, age, and gender of the\npatient with the recurrent episodes of pancreatitis possibly due to obstruction to\nupstream pancreatic duct by the cystic lesion.\nThe patient underwent an upper esophagogastroduodenoscopy and ultrasound-guided fine\nneedle aspiration of the cystic fluid was done which showed elevated CEA (370 mcg/L)\nand amylase (621 U l −1 ) levels and was negative for\nmalignant cells. CEA levels above 200 ng ml −1  raise\nsuspicion for a mucinous neoplasm, while amylase levels above\n200 U l −1  raise suspicion of a post-pancreatitis pseudocyst. \n 4\nThe patient underwent a distal subtotal robotic pancreatectomy with splenic\npreservation. The intraoperative findings showed a cystic 3 cm lesion at the\ndistal pancreatic tail. Splenic artery, splenic vein, and the spleen were\npreserved.\nThe histopathology showed a unilocular cyst lined by tall, columnar, non-mucin\nproducing cells with mildly hyperchromatic small nuclei seen focally. Also seen was\na multifocal underlying ovarian-type stromal component. In addition to a focally\nmixed inflammatory infiltrate and foamy histiocytic aggregates with hemosiderin\nladen macrophages reaching the surface.\nImmunohistochemical stains showed spindled cells positive for CD10 and ER and\nepithelial lining from the cyst expressing CK-7 and CK-19 typical of endometrial\nstroma. ( Figure 3 )\nHematoxylin and Eosin staining of the pancreatic cyst. Original magnification\nx400. a. Microscopic sectionof subepithelial cystic space show\nendometrial-type glands with Müllerian type epithelium, partially\ncyclingendometrium, peri-glandular fibrosis with some atrophy and no\nsignificant atypia. b. CD10 immunostain is positivefor endometrial\nstroma.\nThe patient had an unremarkable recovery with no complications observed and was\ndischarged with plans for follow-up at the gastroenterology and gynecology\noutpatient clinics for further evaluation.\n\nEndometriosis can be divided into intrapelvic and extrapelvic disease. \n 3 \n  Commonly it is seen in the pelvis near the uterus, fallopian tubes and\novaries and approximately 20 to 25% of the patients are asymptomatic. \n 5 \n  Extragenital pelvic manifestations are seen in almost 40% of patients and\ninclude rectal deposits, urinary tract, abdominal wall and peritoneal deposits. \n 2,6 \n  Extrapelvic endometriosis is only seen in 1% of patients and the diagnosis\ncan be somewhat challenging and is often delayed. \n 3 \n  Extrapelvic endometriosis can occur at any location and cases have been\ndescribed with deposits to the lungs, liver, pancreas, bones and brain. \n 2\nThere are several theories suggesting the pathophysiology of endometriosis and\ninclude the direct endometrial tissue extension unto neighboring organs, retrograde\nmenstruation, ectopic production of endometrial stoma from embryonic vestiges, bone\nmarrow and stem cells as well as hematogenous or lymphatic spread. \n 6,7\nOn MRI, ovarian endometriomas have a characteristic homogeneous T1 hyperintensity and\na low T2 signal intensity. There may be heterogeneity to the T2 hypointensity and\nthis is referred to as shading and is due to different stages of degradation of the\nblood products as a result of cyclical episodes of bleeding. Another more specific\nsign of ovarian endometriomas is called the T2 dark spot sign which appears as\ndiscrete markedly hypointense foci in the cyst on  T 2 \n  weighted images, with or without the T2 shading. In distinguishing an\novarian endometrioma from other non-endometrioma hemorrhagic cystic lesions, a study\nhas shown T2 shading has approximately 93% sensitivity, 45% specificity, 72%\npositive predictive value (PPV) and 81% negative predictive value (NPV), while T2\ndark spots has a 93% sensitivity, 45% specificity, 72% PPV and 81% NPV. \n 8\nThe endometrioma in our case had atypical imaging features with low T1 signal and\nhigh T2 signal and therefore was not considered as a differential diagnosis.\nPancreatic endometriosis was first described in the literature in 1984 and is\nextremely rare with only 14 cases reported up to the current date. \n 2,6,7,9 \n  Patients with pancreatic endometriosis usually present with epigastric pain\nand may be admitted with acute pancreatitis or acute abdomen. \n 2,7 \n  The cyclical catamenial nature of symptoms and a past medical history of\nendometriosis may aid in suggesting the diagnosis. \n 1,2 \n  In addition to the frequently changing morphological findings and signal\nalterations on sectional imaging may also be helpful. \n 2\nThe wide use of sonography, computed tomography, magnetic resonance imaging and\npositron emission tomography PET resulted in a rise in the incidental recognition of\npancreatic lesions in asymptomatic patients. \n 5,9 \n  Cystic lesions in the pancreas could be classified into benign, premalignant\nand malignant cysts. \n 10 \n  The differential diagnosis includes post-pancreatitis pseudocysts, mucinous\ncystic neoplasms, serous cystadenomas or cystadenocarcinomas, cystic pancreatic\nadenocarcinomas, cystic neuroendocrine tumors and pseudopapillary tumors as well as\nectopic tissue such as endometrial cysts. \n 9,10\nPancreatic pseudocysts typically form within 6 to 8 weeks after an episode of acute\npancreatitis. The imaging features include a round fluid-filled collection and thick\nenhancing fibrotic wall with no septations, wall calcifications or intracystic solid\ncomponents. On cystic fluid analysis elevated amylase and lipase levels are commonly\nencountered with normal CEA levels. \n 10\nMucinous cystic neoplasms typically occur in middle-aged female patients and are\nconsidered premalignant. Approximately 90% are notable at the pancreatic tail and\ncan reach a size of 20 cm in diameter at the time of diagnosis. They are\nmultilocular and internally-septated with a smooth enhancing contour and wall\ncalcifications. These neoplasms are lined with mucinous epithelium with varying\ndegrees of dysplasia resting on a layer of cellular ovarian-like stroma which mimics\nendometrial stroma and is usually positive for inhibin, both oestrogen and\nprogesterone receptors but negative for CD 10 on immunochemistry tests which is a\ncommon marker for endometrial stroma. \n 10\nElevated cyst CEA levels are more common with mucinous cystic neoplasms than\nnon-mucinous lesions and amylase levels are typically normal. \n 10\nDiagnostic imaging and laboratory tests are valuable tools in the initial assessment\nof pancreatic endometriosis. \n 10 \n  However, imaging is usually non-specific due to overlapping features with\npremalignant pancreatic lesions especially with the more common mucinous cystic neoplasms. \n 2,10 \n  Pancreatic imaging may show cystic lesions of a variable size and complexity\nwith varying degrees of hemorrhagic components. \n 2 \n  Magnetic resonance imaging may depict bleeding which appears as hyperintense\nfoci on T1 sequences with/without fat saturation. In the absence of intralesional\nhaemorrhage, hypointense T1 and T2 image signal is usually seen. \n 2,6\nUp to the current date no typical diagnostic imaging features of pancreatic\nendometriosis have been established as only a few cases have been reported in the literature. \n 6 \n  Nevertheless, hemorrhagic components are extremely uncommon in pancreatic\nmucinous tumors. \n 2 \n  Pancreatic endometriomas may show elevated cyst CEA levels as well as\npositive CD 10 immunohistochemical marker which is used to denote endometrial stroma. \n 6,7 \n  Laparoscopy and histopathological analysis remains the gold-standard for the\ndefinitive diagnosis of pancreatic endometriosis. \n 3\nUltrasound-guided fine needle aspiration is not recommended if mucinous cystic\nneoplasms are highly suspected due to the risk of seeding which can cause\npseudomyxoma peritonii. \n 6 \n  If preoperative suspicion of malignancy cannot be ruled out then distal\npancreatic resection with or without splenectomy is recommended. \n 9\nDefinitive diagnosis and treatment of pancreatic endometriosis usually requires a\nmultidisciplinary approach including pancreatic surgeons and gynecologists with the\ncareful surgical excision of all endometrial lesions. \n 1,9 \n  Thorough diagnostic investigations including intraoperative frozen section\nhistopathology may avoid extensive surgical resection leading to complications like\npancreatic insufficiency. \n 2,7 \n  Concomitant evaluation of the pelvic cavity is essential as isolated\nextrapelvic endometriosis is rare. \n 1\nIn conclusion, pancreatic endometriosis is extremely rare but should be considered as\na differential diagnosis for cystic lesions especially in patients who are known to\nhave pelvic endometriosis. Nevertheless, the gold standard for the definite\ndiagnosis of pancreatic endometriosis remains histopathological due to the\noverlapping radiological imaging features with other pancreatic cystic lesions.\n\nEndometriosis is a fairly common disease occurring in up to 5–10% of\npremenopausal females and 5% of postmenopausal females.\nPancreatic endometriosis is extremely rare and often mimics other pancreatic\ncystic lesions including pseudocysts, premalignant and malignant cysts.\nClinical features, radiological imaging and laboratory work-up are essential\nand may aid in suggesting the diagnosis. However, for a definitive diagnosis\nsurgical resection and histopathology are the gold standard as the\nradiological image findings of these lesions overlap with other cystic\nlesions especially premalignant and malignant mucinous neoplasms.","source_license":"CC0","license_restricted":false}