Peripancreatic lymphangioma: When fine needle aspiration changes the diagnosis—Case report and literary review

Lymphangiomas are rare, slow-growing, benign lesions of vascular origin with lymphatic differentiation.^1,2 They uncommonly involve the abdomen and rarely the pancreas.^1–4 Pancreatic lymphangiomas were first described by Koch in 1913 and are extremely rare, accounting for only 1% of abdominal lymphangiomas and less than 0.2% of all pancreatic lesions.^1–3,5 Lymphangiomas are considered to be of pancreatic origin if they occur adjacent to the pancreas, within the pancreatic parenchyma, or connected to the pancreas via a pedicle.^1,3

A 44-year-old white male was referred to a Gastroenterology consultation after an abdominal computed tomography (CT) showed a 22 mm hypodense nodular image located between the inferior vena cava (IVC) and the second part of the duodenum externally to the splenomesaic confluent, whose density suggested a liquid/cystic nature. The physical examination and laboratory test results were unremarkable. An endoscopic ultrasound (EUS) was requested and showed a 23 mm cystic lesion with a well-defined and regular wall located between the IVC and the cephalic portion of the pancreas; the lesion was next to the pancreatic parenchyma, raising the hypothesis of a pancreatic cystic lesion. Fine needle aspiration (FNA) biopsy revealed a milky fluid with a yellowish color that might correspond to lymph, suggesting the possibility of a lymphangioma (Fig. 1). Cytological and biochemical exam of the fluid revealed 18,000 nucleated cells/μL with a lymphocyte predominance and a background of proteinaceous material; an elevated triglyceride value (2953.3 mg/dL); amylase (351 U/L) and carcinoembryonic antigen (CEA) (8.84 ng/mL) within normal limits. All these aspects support the diagnosis of peripancreatic lymphangioma. As the patient was asymptomatic, a conservative approach with imaging surveillance was chosen. The patient will be re-evaluated in six months.

Figure 1.

(A) Peripancreatic cystic lesion (peripancreatic lymphangioma); (B) EUS-FNA of cystic lesion; (C) Milky fluid obtained from EUS-FNA.

Lymphangiomas result from lymphangiectasia, which may be associated with congenital malformations, inflammatory processes, radiotherapy, surgical intervention or previous abdominal trauma.^1–3 These lesions have a female preponderance (unlike our case), have been reported in all age groups and have a variable size (from 3 to 20 cm).^1,3 They are often asymptomatic and discovered as an incidental finding.^2,5 However, the clinical presentation depends on the size, location, mass effect and complications. Common non-specific clinical manifestations include abdominal pain or mass, nausea, vomiting and weight loss, due to the pressure effect.^1,2 Owing to their rarity, this lesion is difficult to diagnose pre-operatively.^2–4 Most of the imaging studies are non-specific.^2,3 EUS can allow a preoperative diagnosis, particularly because of EUS-FNA of the cystic fluid and its consequent cytological and biochemical studies.^2,4,5 Lymphangiomas can be filled with serous, serohematic, or lymphatic fluid.¹ Milky white fluid with a triglyceride level greater than 5000 mg/dL is diagnostic of lymphangioma. Amylase and CEA should be measured to rule out epithelial lesions and pseudocysts. Cytological examination shows a high population of small mature lymphocytes.^2,3 There have been no reports of malignant transformation.⁵ As so, when there is a definitive diagnosis, the patient is asymptomatic and the lesion is not locally invasive, a conservative approach with imaging surveillance can be undertaken, as was the choice in our case.^1,2,4,5 Although lymphangiomas are benign neoplasms, they can be locally invasive and may involve adjacent organs. Complete surgical excision is the curative treatment, providing excellent prognosis and very low incidence of recurrence.^1–4

It is very important to consider this entity as a differential diagnosis of cystic pancreatic lesions, in order to avoid unnecessary or aggressive treatments.

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