Cystic lymphangioma of the pancreatic head treated by enucleation: Case report and literature review

Introduction The widespread use of imaging methods has led to an increased identification of asymptomatic Pancreatic Cystic Lymphangiomas (PCL), a rare entity for which available information is very limited. Presentation of case We present the case of an asymptomatic 61-year-old male, submitted to elective enucleation of a pancreatic head PCL at our institution. After four years of follow-up the patient is doing well and has no clinical or imaging signs of recurrence. Discussion Though rare, PCL should be included in the differential diagnosis of pancreatic cystic neoplasms. All efforts should be made to ascertain a preoperative diagnosis, as expectant follow-up could be a reasonable approach in asymptomatic patients and/or poor surgical candidates. In the face of an uncertain diagnosis, complete surgical excision may be the treatment of choice. Conclusion The medical community worldwide should be encouraged to report all cases of PCL, as to increment the overall knowledge about this lesion.


Introduction
Widespread use of cross-sectional abdominal imaging has resulted in increased identification of pancreatic cystic lesions in asymptomatic patients [1,2]. Pancreatic Cystic Lymphangioma (PCL) is one of those rare cystic neoplasms for which available information is very limited.
Lymphangiomas are a benign form of lymphatic malformations that lead to blockage of local lymph flow and lymphangiectasia [2][3][4][5]. A well-established theory suggests that lymphangiomas arise from sequestrations of lymphatic tissue during embryologic development [1,3,5]. Abdominal trauma, inflammation, surgery or radiation therapy may lead to lymphatic obstruction and secondary formation of such a tumour [3][4][5]. The vast majority of lymphangiomas can be found in the neck region (75 %) and axillary (20 %) and only a small percentage (<1 %) appears in the mesentery region or in the retroperitoneal space. Lymphangiomas arising from the pancreas are extremely rare [1][2][3].
Although these lesions are benign, they can often present a diagnostic dilemma as imaging findings are characteristic and can point to the diagnosis, however, confirmation with fine needle aspiration and histopathologic correlation is necessary [1][2][3][4][5]. Also, the treatment is extremely various; it consists from en bloc resection to simple observation and more or less tight follow up [1,3,4]. This work has been written in accordance with the SCARE criteria [6].

Presentation of case
A 61-year-old asymptomatic male, without significant past medical history, in particular abdominal trauma or pancreatitis, was referred to our institution after the incidental finding, during a routine renal ultrasound (US), of a polycystic lesion between the pancreas and the left liver lobe, with anechoic content and fine septa, measuring 76x63x61 millimetres (Fig. 1). Computed tomography (CT) scan (Fig. 2) characterized the lesion as being on the dependence of the pancreatic head and proximal body (which was otherwise of unaltered morphology); no local invasion, lymphadenopathy or ascitis was detected. No laboratory abnormalities were found.
Endoscopic ultrasound (EUS) further revealed absence of associated wall thickening, mural nodules, solid masses or connection with main pancreatic duct. A 22-gauge EUS-FNA was performed to aspirate approximately 5 mL of a yellow-white thick fluid, with CEA level of 0,6 ☆ The authors have no potential conflict of interest.There were no funding sources. ng/mL, Amylase level of 297 U/L; a triglyceride level was unable to be obtained due to partial solidification of material prior to analysis. Cytology was negative for malignancy and showed only scattered mature lymphocytes and no epithelial cells.
Given the volume of the lesion, uncertainty of the diagnosis and patient's preference, he was admitted for surgical exploration, performed by hepatobiliopancreatic surgeon. After a right subcostal incision, with no evidence of locally advanced or metastatic disease, we proceeded to enucleation of the lesion. Fresh frozen sections confirmed benign disease and complete resection. Pathology report a multilocular tumour with 2 to 3 cm cysts filled with yellow-white bloody fluid and, microscopically (Figs. [3][4], with walls and septa made of connective tissue with some lymphoid follicles and lymphatic endothelial lining (strongly reactive to D2-40 immunohistochemistry), classifying the tumour as a Pancreatic Cystic Lymphangioma.
Patient had uneventful postoperative course in the surgical ward, with mobilization and oral intake initiated in first postoperative day, discharged at the 7th postoperative day. Four years of follow-up have now been completed with no evidence of recurrence or other complaints.

Figs. 1.
Ultrasound showing a polycystic lesion with fine septa, measuring approximately 76 × 63 × 61 mm, without calcifications or vegetations, located between the pancreas and the left liver lobe.
The clinical presentation is nonspecific, sometimes related to compression of neighbouring organs, often including vague abdominal pain and a palpable mass. Pedicle torsion, rupture, infection or haemorrhage into the lymphangioma may cause acute abdominal symptoms. As in our case, a growing number of patients reported were asymptomatic with incidental diagnosis of lymphangioma on physical examination or radiographic studies for unrelated diseases [1][2][3][4][8][9][10].
The cystic nature of the lymphangioma encompasses a broad differential diagnosis (Table 1).
Preoperative diagnosis using EUS-FNA has been reported, based on: gross appearance of the aspirated fluid (chylous); elevated triglyceride levels (<3000 mg/dL) in the cyst aspirate, with or without the presence of numerous lymphocytes; or the characteristic tissue architecture on paraffin embedded cell-blocks from the aspirates [4,8,9]. As in this case, triglyceride level may be unable to obtain due to partial solidification prior to analysis [8]. Analyzing fluid for amylase, CEA and cytology can help further narrow the differential [8].

Conclusion
In this study, we report a very rare case of cystic lymphangioma of the head of the pancreas. Despite being benign and mostly asymptomatic, we believe that it should be considered in the differential diagnosis of cystic tumors of the pancreas. Complete surgical excision has the dual advantage of allowing definitive diagnosis and treatment, however, asymptomatic cases with no suspicion of malignancy in the diagnostic study, observation with clinical and radiologic follow-up may be favoured.

Sources of funding
Authors did not receive funding for this research.

Ethical approval
Not applicable.

Consent
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Provenance and peer review
Not commissioned, externally peer-reviewed.