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Abstract
Pancreatic endometriosis is an extremely rare condition, with only a few cases described in the literature. Definitive diagnosis is often difficult to elucidate and will almost always require biopsy or surgical resection. We present a case of a female in her early thirties with a well-known history of widespread endometriosis presenting with vague epigastric pain. CT imaging showed an 11 cm well-circumscribed simple-appearing cyst in the lessor sac. Its origin could not be determined preoperatively but it appeared to involve the parenchyma of the body of the pancreas. Due to the associated pain and indeterminate nature, subtotal surgical resection of the extrapancreatic cyst was performed with the intrapancreatic cyst being managed by a cystogastrostomy to the adjacent stomach in a planned pancreas-sparing procedure following intraoperative confirmation it was arising within the pancreas. Pathological evaluation of the resected cyst confirmed it to be an endometrial cyst. The cystogastrostomy anastomosis subsequently obstructed a few weeks postoperatively and symptoms recurred from cyst enlargement. Redo robotic resection with resection of the remnant cyst, cystogastrostomy and en bloc spleen-preserving distal pancreatectomy was performed. The patient had an uneventful recovery. She has had no recurrence of cyst or symptoms since. A procedure video is included in the report.
- pancreas and biliary tract
- reproductive medicine
- drug therapy related to surgery
- general surgery
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Background
Endometriosis is a relatively common condition in which ectopic foci of uterine endometrial cells are found growing outside of the uterus. It affects between 5% and 10% of reproductive age women and is characterised by intense pelvic pain, dyspareunia, infertility, dyschezia, among other symptoms.1 2 Often described as ‘cigarette burn’ lesions, the endometrial tissue implants can appear on nearly every pelvic or intra-abdominal structure and cause significant pain.3
The pathophysiology of endometrial spread is complex and yet to be well defined. Current theories include Sampson’s retrograde menstruation—in which the endometrium travels backwards through the fallopian tubes to seed the peritoneum—and other, less popular, theories involving ectopic production of endometrial stroma from embryonic vestiges, bone marrow or other stem cells.3–5 Lymphatic or vascular spread has also been considered as an explanation for the more distant endometrial implant sites where this tissue can be found.6 However, no single theory has been able to fully explain all manifestations of this complicated disease process. Another manifestation can be seen in the formation of cystic structures comprised endometrial tissue and other tissues in ectopic locations.7 As most of these cysts affect the pelvic structures, endometriotic cysts in the pancreas have only been described in the literature 14 times since 1984.1 Another rare seeding site is the appendix.3 It is reported that only 2.8% of patients with endometriosis develop appendiceal endometriosis.8
Little has been written regarding the appropriate diagnostic protocols, management and follow-up for patients with pancreatic endometriosis. Patients with pancreatic endometriosis usually present with a epigastric pain. Accurate preoperative diagnosis can prove to be a challenge; so precise history taking, appropriate imaging, and relevant laboratory findings may be suggestive and guide the physician. However, in all of the 14 published cases, surgical resection was required to fully characterise the cyst for accurate diagnosis.
Adequate documentation and reporting of these rare cases is important for advancement of knowledge and future understanding of this condition to provide the best care possible for these patients. We, therefore, present a case of a woman in her early thirties with a known history of endometriosis who was found to have a cyst in the body of her pancreas. We have included video documentation of the the surgical resection with en bloc distal pancreatectomy procedure (video 1).
Case presentation
A woman in her early 30s with a medical history of endometriosis presented to an urgent care clinic with a acute-onset upper and mid abdominal pain. She denied other symptoms including nausea, vomiting, constipation, fevers or weight loss. The patient followed up with gastroenterology shortly thereafter. A CT of the abdomen and pelvis was obtained, showing an 11 cm by 7.5 cm by 7 cm simple cystic mass in left upper abdomen, medial to the lesser curvature of stomach and inseparable from anterior aspect of body of the pancreas; the latter was not well visualised due to the size of the mass. Aetiology of the cyst was uncertain, but was thought to possibly represent a gastrointestinal duplication cyst or a pancreatic pseudocyst.
MRI confirmed a cyst in the left upper quadrant with mass effect on the pancreas and stomach. Differential diagnosis was expanded to include a possible enteric duplication cyst. An oesophagoduodenoscopy and colonoscopy done during this time showed no acute findings and the patient was referred for surgical evaluation.
She presented to the surgery clinic 3 months after her emergency centre visit. She reported pain throughout this course. Two weeks later, she was taken to the operating room for a robotic potentially pancreas-sparing cyst resection, possibly with cystogastrostomy. See details under the section‘Treatment’.
Investigations
The patient’s endometriosis had been discovered 11 years prior, at which time she initially presented with abdominal pain. A CT scan at the time led to suspicion of appendicitis. She underwent a laparoscopic appendectomy and was subsequently diagnosed with appendiceal endometriosis via pathological report. It appeared that the endometrial deposits had been the cause of the appendicitis.
One month prior to the current presentation detailed in this report, the patient presented to the emergency department due to vague diffuse abdominal pain. At this time, a CT scan showed an 11 cm cyst that was separate from the pancreas and stomach. The patient was discharged home on antibiotic therapy to follow up in 1 week. This was further evaluated by MRI of the abdomen but both imaging investigations were not able to clearly characterise the cyst preoperatively or tell the exact origin of the cyst. No biopsy was considered given the imaging appearance of the cyst and since the patient warranted operative intervention for associated symptoms. The patient did undergo upper and lower endoscopic evaluation prior to being referred for surgical evaluation.
Differential diagnosis
For the patient’s 11 cm upper abdominal cystic mass, the differential diagnosis was a mesenteric duplication cyst versus pancreatic pseudocyst versus endometrioma. The endometrioma, though rare could be strongly considered preoperatively given her long-term history of endometriosis.
Other differential diagnoses include mucinous cystic neoplasm, intraductal papillary mucinous cystic neoplasm and serous cystic neoplasm. However, imaging appearance was not classic for these latter three types of cysts.
The patient’s latest presentation and topic of this report revealed a large pancreatic cystic lesion on CT which was believed to be a mesenteric duplication cyst, pancreatic pseudocyst or endometrioma based on size and location.
Treatment
Treatment of endometriosis is multifactorial and heavily dependent on the specific patient. For this woman, a combination of surgery and hormonal regulation via birth control was used to control the physical symptoms and spread of her condition. However, it is believed that the abrupt change from the combined pill to the Depo-Provera shot may have disrupted that hormonal balance, leading to the most recent flare of her endometriosis. After the most recent surgical resection, she has remained on the Depo-Provera shot with no further complications or recurrences.
The patient was taken to the operating room for a robotic potentially pancreas-sparing cyst resection, possibly with cystogastrostomy. Intraoperatively, the cyst appeared simple and was originating from the body of the pancreas. In order to preserve the body and tail of pancreas, the extrapancreatic portion of the cyst (approximately 70% of the cyst) was resected and the intrapancreatic portion (about 30%) was anastomosed to the stomach via a hand-sewn cystogastrostomy. The pathology report from this procedure showed an endometrioid cyst with immunohistochemistry stain CD10 highlighting the endometrial stroma.
At the patient’s 2.5-month postoperative follow-up, she reported recurrent epigastric pain not associated with her menstrual cycle. Repeat CT scan of the abdomen showed a 4 cm thick-walled cystic structure with a small amount of internal air, located in the pancreatic body at site of the prior subtotal cyst resection and cystogastrostomy.
She was taken back to the operating room 2.5 weeks later and a robotic spleen-preserving distal pancreatectomy en bloc with complete resection of the endometrial cyst was performed. This was successful, and the cyst was found to contain foul-smelling pus on the back-table intraoperative evaluation, consistent with transformation into a cyst abscess. The pathology report on the fully resected cyst showed findings consistent with fibrinopurulent exudate and granulation tissue lining the cyst, bounded by fibrotic scar with hyperabundant eosinophils and plasma cells, consistent with cyst infection from entry of gastric contents into cyst, followed by subsequent occlusion of the cystogastrostomy anastomosis and subsequent development of infection and cyst abscess. The endometrial lining was, therefore, destroyed and transformed to an abscess cavity lining. The was associated pericystic pancreatitis.
There were no complications from this procedure and the patient has been doing well, with no recurrent symptoms or complications until the writing of this report 6 months postoperatively.
Outcome and follow-up
As of the date of this report—6 months postoperative—the patient has had no complications or recurrences, and continues to be asymptomatic. Despite resection of 50% of her pancreas en bloc with the endometrial cyst, she has not developed any features of pancreatic insufficiency. Her follow-up visits are now on an as-needed basis and she has been instructed to follow up with her primary care physician with any issues regarding glucose monitoring following the pancreatic resection. She continues to use the Depo-Provera shot.
Discussion
Endometriosis is a complicated condition with many manifestations. In a study performed in 2015 of 1350 women with proven endometriosis, the most common site of extrauterine tissue deposition was the ovaries (96.4%), followed by soft-tissue (2.8%), gastrointestinal structures (0.3%) and urinary tract (0.2%).9 In 60% of cases, endometriosis presents in the uterus or other pelvic structures and treatment of such is well documented. However, it is the other 40% of extrauterine presentations that are more difficult to manage. In this report, we presented a patient with not one, but two extremely rare cases of abdominal endometriosis. It is reported that endometriosis of the appendix presents in only 2.8% of patients, and only 14 patients with endometriosis in the pancreas have been presented in the literature since 1984, as stated previously.1 The current theory for endometrial spread combines the three previously separate theories of implantation, lymphatic or vascular spread and direct extension. The seeding of intra-abdominal structures far from the pelvis in this case could lend credence to the vascular or lymphatic theory or that maybe some patients are predisposed to more far-reaching lesions than others. More investigation is certainly warranted in regards to this question.
Surgical resection of the large pancreatic cyst was necessary in this case for symptom resolution and pathological evaluation, which led to the final diagnosis of endometrial spread to the pancreas. Preoperative diagnosis of pancreatic endometriosis is feasible via Endoscopic Ultrasonography or imaging-guided biopsy. However, diagnosis is often only achieved postoperatively as was the case with this patient. Biopsy was not pursued here, since it would not have changed her plan of management. Retrospectively, her multiple bouts of appendicitis were determined to be a result of her underlying endometriosis. Rarely does one disease process explain two such unrelated presentations but it would appear that this patient’s endometrial tissue had a propensity for affecting abdominal structures rather than pelvic ones.
Additionally, the abrupt worsening of this patient’s condition following the switch from the combined birth control pill to a progesterone-only option is intriguing. This would point to either a loss of oestrogen or a rebound increase of the hormone as being responsible for the worsening of her symptoms. Given that extrauterine endometrial tissue overexpresses oestrogen receptors and is generally dependent on this hormone to proliferate, the latter explanation is most likely.10 In reporting this occurrence, we hope to provide a word of caution to providers who are managing hormonal treatments for patients with endometriosis. A more gradual and carefully monitored transition between contraceptives should be employed in these patients, particularly when they are known to have aggressive and widespread lesions.
The purpose of this report is to share not only a rare and interesting case, but to encourage physicians treating endometriosis to possibly watch patients with widespread lesions more carefully. The recurrence and speed with which this patient’s cyst grew is alarming and her outcome may not have been as successful had careful monitoring of her imaging not occurred. We also urge providers to use caution when transitioning contraceptives in these patients, as hormonal disruptions can cause a flare in symptoms, as with this patient. It is our hope that this rare case may supplement the limited knowledge of endometriosis that exists in the literature today and in turn, help provide the best care for these patients as possible.
Learning points
Endometriosis is a complicated condition with multiple manifestations that can often be mistaken for appendicitis or other gastrointestinal pathology.
Endometrial lesions of the pancreas are rare but can be serious if not diagnosed properly; these can be rapidly growing cysts that should be surgically resected as soon as possible.
In patients with a known history of distant endometrial metastasis, clinical suspicion must be elevated for future far spread endometriosis.
Ethics statements
Patient consent for publication
Footnotes
Twitter @Eduhpdmd
Contributors CL created the original manuscript. AK contributed towards the bulk of the editing. MLW edited the manuscript and created the supplemental video. EO supervised and edited the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.