The presence of chylous fluid with high triglycerides levels on endoscopic ultrasound- (EUS-) guided fine needle aspiration (FNA) is very pathognomonic for the diagnosis of cystic lymphangiomas of the pancreas. In our case report the puncture of the pancreatic cyst showed a typical milky fluid though measurable triglyceride concentrations were absent in the laboratory. Two possible explanations were found. First of all grossly lipemic samples show a slower rate of color development than do clear serums which can produce a false negative result if the sample is insufficiently diluted. Secondly, high lipase levels can divide triglycerides in glycerol and fatty acids, making the concentration of triglycerides undetectable.
Cystic lymphangiomas are benign cystic tumors which arise from the lymphatic system due to blockage of the lymphatic flow which can be congenital or due to inflammation, trauma, or cancer. Lymphangiomas occur mostly in children, especially found in the neck (75%) and axillae (20%) but they can be found anywhere in the body [
We present the case of a young woman with a pancreatic cyst where EUS-FNA showed a typical milky fluid but without measurable triglyceride concentrations. In this case report we try to explain this atypical biochemical finding.
A 29-year-old female was evaluated for mild episodes of chronic pain in the right hypochondriac region which worsened for a few days. She also complained about constipation and mild dyspepsia. Medical history showed a scoliosis and exercise-induced asthma. Physical examination did not reveal any abnormalities. Routine laboratory tests were unremarkable. An ultrasound of the abdomen was performed and showed a cystic lesion (diameter 5.6 cm), adjacent to the gall bladder. Subsequently, a contrast-enhanced computer tomographic scan and MRI were performed and showed a large multiloculated cyst (28 × 33 × 46 mm) with multiple thin septa in the head and neck of the pancreas (Figure
Abdominal CT scan showing a large cystic lesion in the head of the pancreas.
An endoscopic ultrasound (EUS) was performed and confirmed the presence of a large multiloculated cyst (5 × 5 cm) with clear borders, without nodules, calcifications, or perilesional lymphadenopathy. There were micro- and macrocystic components with thin septa and a clear anechoic content. The remaining pancreatic parenchyma was normal. EUS-guided aspiration with a 22G needle demonstrated chylous liquid (Figure
Overview of the biochemical aspects of the aspirated fluid.
EUS-FNA | EUS-FNA | |
---|---|---|
Triglyceride (mg/dl) | <10 | <10 |
Amylase (U/L) | 578 | 3788 |
CEA ( | 1.7 |
Sample showing the milky aspect of the aspirated fluid from the cystic lesion.
Cytological examination showed a hypocellular monster with only rare lymphocytes and neutrophils. There were no epithelial cells. There were no arguments for malignancy.
The diagnosis of a cystic lymphangioma was withheld based on the macroscopic chylous aspect of the fluid, cytological examination, and negative CEA measurement. A conservative policy was agreed on with a follow-up by MRI within 6 months.
Cystic lymphangiomas are rare multiloculated soft cystic masses, with flat endothelial cells that line the cyst wall. The cysts are variable in size and composed of dilated lymphatic channels that are divided by thin septa [
Pancreatic cystic tumors are a diagnostic challenge because conventional imaging studies cannot characterize most lesion with sufficient certainty. The differential diagnosis of a cystic pancreatic lesion is broad including serous and mucinous cystadenoma, mucinous cystadenocarcinoma, pseudocysts, intraductal papillary mucinous tumors (IPMT), cystic neuroendocrine tumors (NET), solid pseudopapillary tumor, parasitic cysts, or necrosis/cystic degeneration of ductal carcinoma [
As lymphangiomas are benign tumors without malign potential, treatment depends on the symptoms. In symptomatic patients complete excision is curative but in asymptomatic patients treatment is conservative [
The diagnosis of lymphangioma of the pancreas has often been established after surgery. However, since the development of EUS-FNA, diagnosis is based on high triglyceride levels alone or on a combination of high triglyceride levels and numerous lymphocytes in the aspirate [
A first possible explanation can be found in the test itself (TRIG, Vitros 4600, Ortho Clinical Diagnostics; enzymatic, colorimetric; glycerol phosphate oxidase/peroxidase). The concentration of triglycerides is based on a coloring reaction in the laboratory. Grossly lipemic samples show a slower rate of color development than do clear serums, producing a false negative result. To prevent this, samples should be sufficiently diluted before testing [
Another explanation can be amylase in the fluid. Due to the high levels of amylase we presume a high lipase concentration. A high lipase level will divide triglyceride in glycerol and fatty acids making the concentration of triglycerides undetectable (see (
Pancreatic lymphangiomas are rare benign tumors. The diagnosis is generally based on the FNA results with macroscopic milky appearance of the fluid with high triglyceride levels. However, milky fluid without high triglyceride levels can be explained by the coloring reaction of the test itself, where grossly lipemic samples show a slower rate of color development than do clear serums. The second reason can be found in the high lipase concentration in the fluid which divides triglycerides in glycerol and fatty acids, making the concentration of triglycerides undetectable.
There are no conflicts of interest and no financial interest to declare.