Splenic and retroperitoneal lymphangioma in an adult: a case report

Clinical History

21-year-old woman presented with diarrhoea for 4 weeks, abdominal distension and diffuse supraumbilical pain without fever and eosinophilia. Stools had mucus but no blood or pus. She had loss of appetite for a long time. The episode was self-limiting and the standard tests only showed the incidental imaging findings.

Imaging Findings

An abdominal ultrasound showed multiple cystic splenic lesions without septa, the largest of 1.4 cm in size (Fig. 1) and mild ascites.
Computed tomography (CT) with intravenous contrast confirmed the cystic splenic lesions (Fig.1) and also showed a retroperitoneal, well-defined, hypodense (27-30 United Hounsfield -UH-) mass surrounding great vessels from origin of celiac trunk to iliac bifurcation, of 7.4 x 1.6 cm of maximum transverse per anteroposterior diameters (Fig. 3). It encases the aorta, its visceral branches, inferior vena cava and renal veins without compressing or infiltrating them. Cystic splenic lesions and retroperitoneal mass had similar cystic appearance and they showed no internal enhancement (Fig. 1 and 3).
No abdominal lymphadenopathies were seen. Ascites of 15 UH (no haemoperitoneum) was confirmed.
Magnetic resonance imaging (MRI) showed the same findings as CT (Fig. 2, 4 and 5).
There was no change of the splenic cysts or of the retropertioneal mass after one year (Fig. 6).

Discussion

Cystic lymphangioma is a benign neoplasm originating from a malformation of the lymphatic system [1, 2]. It generally occurs under the age of 2 years and is very rare after 20 years of age [2, 3]. There is no difference in the incidence between sexes [1, 2].

The most commonly involved sites are the neck (75%) and axilla (20%) [1, 2, 4, 5, 6, 7]. It is infrequent (5%) in the omentum, gastrointestinal track, retroperitoneum, abdominal viscera, mediastinum, lung and bone [2, 4, 8].

The two hypotheses for the pathogenesis of lymphangioma are abnormal congenital development, bleeding or inflammation of the lymphatic system which causes an obstruction of lymphatic channels or both [2, 4].
Clinical manifestations of lymphangioma are left upper quadrant pain, abdominal distention, loss of appetite, nausea, vomiting, palpable mass, rarely ascites, bleeding, torsion or rupture [2, 4, 5] and it can even be asymptomatic [4, 2].

It is usually found incidentally during ultrasound or CT examinations [4].
Findings in imaging techniques contribute to a more accurate diagnosis of this condition, which can sometimes avoid the use of invasive techniques or even surgical procedures to reach the diagnosis. Ultrasound typically shows septated cystic structures and predominantly anechoic content, with CT attenuation coefficients similar to water [7] usually without internal enhancement [4]. The signal pattern of lymphangiomas on MR resembles that fluid: low signal intensity on T1-weighed images and high signal intensity on T2-weighed images. The presence of haemorrhage or infection may alter echogenicity, CT attenuation and MR signal pattern to give a more solid appearance [8].
Splenic lymphangiomas may be single or multiple. Usually they are small multicystic, thin-walled subcapsular proliferations that are difficult to distinguish from either haemangioma or mesothelial cysts [8].

Our patient is a young adult woman incidentally diagnosed of a retroperitoneal and splenic lymphangioma during a gastroenteric event. Retroperitoneal and splenic involvement makes it especially unique. We have found only one similar case in the literature [2]. The key to diagnosis is the fact that it is a retroperitoneal cystic lesion homogeneously hypodense (15UH) showing no enhancement after intravenous contrast and with non-invasive and no aggressive behaviour, besides being associated with similar cystic lesions in the spleen and no associated lymphadenopathy or other tumours.
Confirmatory invasive or therapeutic tests were dismissed in the absence of symptoms and by patent's refusal. Subsequent controls demonstrated the stability of the findings.

Differential Diagnosis List

Final Diagnosis

Splenic and retroperitoneal lymphangioma

URL:	https://www.eurorad.org/case/10479
DOI:	10.1594/EURORAD/CASE.10479
ISSN:	1563-4086