Lymphangiomas arise due to abnormal development of the lymphatic system. The first description of this condition is attributed to Koch in 1913 [1]. Various theories relating to their pathogenesis have been postulated including blockage of normal growth of embryonic lymphatic channels, inability of the lymphatic sacs to join the venous drainage system and laying of lymphatic tissue in a wrong area.

An eight-year-old boy presented in the outpatient department with complaints of intermittent, dull-aching upper abdominal pain since 6 months. There was no history of trauma, loss of appetite or weight loss. The patient was not on any medications. He was well-built and well-nourished. Abdominal examination showed a large non-tender mass in the left upper quadrant. Routine laboratory evaluation did not reveal any abnormality. Erect X-ray abdomen showed a soft tissue mass in left upper quadrant with paucity of bowel gas in abdomen. Ultrasonography of the abdomen revealed a large anechoic lesion in the retroperitoneum. Computed tomography scan of abdomen and pelvis showed a large, thin-walled, hypo-dense, well-capsulated cystic mass of 10x14.3x15.8cm in size on left side of abdomen, pushing the stomach and bowel onto the right. It was occupying more than 50% of the abdomen. There was no calcification or post-contrast enhancement (Figure 1). The fat planes were maintained. The child was explored under general anaesthesia through left subcostal incision with small extension onto the right. On exploration, a huge, well-defined, dumb-bell shaped mass was noticed in the lesser sac (Figure 2). The mass was seen to be hanging from the pancreatic tail, which was otherwise unremarkable (Figure 3). The spleen was displaced upwards. Complete careful excision of the mass was done taking care not to injure the surrounding organs especially tail of pancreas and the splenic vessels. There was no communication with the pancreatic duct.

Figure 1: A contrast-enhanced helical CT scan of abdomen during portal venous phase shows a huge, hypo-dense, well-capsulated cystic lesion of unknown origin in left upper quadrant of abdomen.

Figure 2: A huge, well-defined mass in the lesser sac.

Figure 3: Operative photograph showing large, dumb-bell shaped cyst densely adherent to the tail of pancreas .

The resected mass had a smooth outer surface and appeared tensely cystic. On sectioning, brownish serous fluid oozed out. The inner surface was greyish white in color with no obvious solid areas. Microscopic examination showed sections containing fibrous cyst wall with thin walled lymphatic vessels, few of which showed presence of lymphocytes. Lymphoid aggregates were seen in the surrounding tissue (Figure 4). On immunohistochemistry, the lining cells were positive for CD34 and calretinin negative. Based on the microscopic as well as IHC findings, diagnosis of PCL was made. The patient’s post-operative course was uneventful. He was allowed orals from post-operative day 3 and discharged on post-operative day 5. The wound healed well.  Presently, at follow up of two years, he is totally asymptomatic and has normal ultrasonography scan.

Figure 4: Microscopic picture of the cyst wall lined by thin attenuated endothelial cells and fibrotic stroma. Attached pancreas showing mild atrophy (H and E; amp ×40).

Lymphangiomas are found in all locations where normal lymphatic ducts are present [2]. They occur in all age groups with a slight female predominance. They are classified as capillary lymphangioma, cavernous lymphangioma, cystic lymphangioma (CL) or cystic hygroma. The capillary and cavernous types mostly present as cutaneous lesions; while CLs predominantly occur in the abdomen (in the mesentery) and retroperitoneum [2]. Lymphangioma of the pancreas is extremely rare with fewer than 60 published cases [3].

CLs are usually benign but can be locally invasive. They are often discovered incidentally. In symptomatic cases, presentation depends on the location and size of mass. Patients can present with epigastric pain, abdominal distension, weight loss or a rapidly growing abdominal lump [4,5]. Though, imaging studies (like CT and MRI) are a guide to location and size of the mass and it’s relation to the surrounding structures; accurate preoperative diagnosis may not be possible. In fact, in quite a few cases diagnosis is established post resection based on histopathological and immunohistochemical analysis. In our case, CT scan showed large thin-walled cystic mass on left side, in the retroperitoneum measuring 10x14.3x15.8cm with no calcification and no post-contrast enhancement. Fat planes were well maintained.

IHC staining is an accurate way to diagnose CL of the pancreas with the combination of multiple IHC markers including CD-31, CD-34, VIII-R, and D2-40 helping to improve the diagnostic rate [6]. In our case, the endothelial lining cells were positive for CD34 and were calretinin negative.

Complete surgical excision remains the treatment of choice as these masses, though benign, do have a propensity to grow and invade surrounding structures [7]. Depending on the morphology and size of the tumor the surgical options are varied; ranging from simple excision of the mass to a pancreatic resection, such as distal pancreatectomy [8]. Complete surgical excision of the cyst was done in our case. The child tolerated the procedure well, is totally asymptomatic and recurrence free at follow-up of two years.

PCL is a rare clinical entity which can present a diagnostic dilemma.  It can be conclusively diagnosed only by histopathological examination of the surgical specimen after excision. Although benign, lymphangiomas can be locally invasive and can recur. Hence, it becomes important to have a high index of suspicion to recognize this lesion as well as remove it in toto.

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