Teaching Case

A 43-year-old male patient, with no previous personal or surgical history and no previous imaging tests, underwent a scheduled ultrasound due to digestive discomfort in the right upper abdominal quadrant. Physical examination and blood tests showed no relevant findings.

Ultrasonography identified a 2.7 x 2 cm liver cyst, located peripherally in the anterior part of segment IVa, with slightly lobulated morphology, showing a thin wall, two thin septations inside and echogenic contents that moved when changing in the patient's position (Figure 1). No mural nodules were identified. No flow was identified in the Doppler study. No other relevant findings were found. In order to characterise the cyst, it was decided to perform an MRI.

Liver MRI identified a nodular subcapsular lesion with well-defined borders in liver segment IVa and two thin septations. The lesion was slightly heterogeneous predominantly hypointense in T1-weighted images and predominantly hyperintense in T2-weighted sequences, in both sequences with areas isointense with liver parenchyma (Figures 2 and 3). The lesion showed no restricted diffusion and it did not enhance after paramagnetic contrast injection (Figures 4 and 5).

Background

Ciliated hepatic foregut cysts (CHFC) are rare congenital cystic lesions of the liver, having an increasing incidence probably due to improvements in imaging techniques [1, 2]. In most cases, CHFC present as solitary subcapsular lesions (mean diameter of 4 cm), usually in segment IV [2,3]. This location is justified because during early embryologic development, the bronchial remnants of the foregut would be trapped in the liver [1]. Histopathological characteristics are pathognomonic; typically, a single, unilocular cyst presenting four layers: an outer fibrous rim; a smooth muscle layer (often incomplete); subepithelial connective tissue; and an inner lining of ciliated, pseudostratified, mucin-secreting columnar epithelium [1-4].

Clinical perspective

CHFCs are usually diagnosed in middle-aged patients generally asymptomatic or presenting vague abdominal symptoms, probably due to their location, which causes distension of Glisson's capsule. Large lesions may cause compressive symptomatology and portal hypertension [2, 5].

Imaging perspective

At US, CHFCs are usually visualized as solitary cystic and anechoic lesions; although they occasionally present internal echoes [1, 2]. CHFCs are rarely multiloculated or septated. In basal CT they are hypodense rounded liver lesions, although this density may vary depending on the cyst contents [1]. After contrast administration, CHFCs usually do not enhance, but it has been reported that up to one-third of the lesions may have a solid appearance [2]. Typical MRI features are a hyperintense cyst on T2-weighted images and a variable signal intensity on T1-weighted images with no contrast enhancement [1,2,5].

Outcome

The management of CHFC is not well established due to the rarity of the condition and diagnostic uncertainty or misdiagnosis frequently results in surgical exploration [1]. CHFCs usually have a benign course, but malignancy has been described in up to 3-5% of cases, in the form of squamous cell carcinoma, mainly in larger lesions, with poor survival [1-4]. Therefore, the treatment of choice for most of these lesions seems to be surgical [2,4]. The laparoscopic approach is a feasible and recommendable option due to the small size of these lesions and their anterior location [2]. In our case, the patient underwent laparoscopic surgery for resection of the lesion, with no complications during the procedure or postoperatively. The suspected diagnosis of ciliated hepatic foregut cyst was confirmed by pathological examination (Figure 6).

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