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Mass in a fatty liver
  1. Dirk J van der Windt1,
  2. Gregory C Wilson1,
  3. Ioannis A Ziogas1,
  4. Samer Tohme1,
  5. Alessandro Furlan2,
  6. Michael A Nalesnik3,
  7. David A Geller1
  1. 1Department of Surgery, Division of Hepatobiliary and Pancreatic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
  2. 2Department of Radiology, Abdominal Imaging Division, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
  3. 3Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
  1. Correspondence to Dr Dirk J van der Windt, University of Pittsburgh Medical Center, Liver Cancer Center, UPMC Montefiore 7 South, 3459 Fifth Ave, Pittsburgh, PA 15260, USA; vanderwindtd{at}upmc.edu

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Introduction

A 39-year-old man was referred to our clinic for liver diseases for a liver mass incidentally found on CT done to rule out kidney stones (figure 1A). In our clinic, he was asymptomatic with regular bowel habits. He denied episodes of jaundice, did not have skin tattoos, never smoked or used illicit drugs and rarely consumed alcohol. His lifestyle was sedentary, and his diet consisted predominantly of fast food. His medical history included arterial hypertension and hyperlipidaemia. Several years prior, he had undergone a laparoscopic cholecystectomy. His obese abdomen (body mass index 36 kg/m2) was non-tender to palpation. On laboratory analysis, white blood cell count, haemoglobin, platelet count, bilirubin, liver transaminases and international normalised ratio (INR) were within normal limits. Hepatitis A, B and C serologies were negative. Serum tumour markers alpha-fetoprotein and CA19-9 were not elevated. Haemoglobin A1c was 6.1%. To further characterise his liver mass, contrast-enhanced MRI was performed, which revealed a fatty liver with a 2.5 cm lesion in segment 4B (figure 1B–D). During laparoscopic surgical resection, a cystic-appearing mass was encountered that drained thick mucus on decompression (figure 2).

Figure 1

Unenhanced CT image (A) shows a 2.5 cm hyperdense, subcapsular lesion (arrow) in segment IV of a fatty, low-density liver. The lesion appears hyperintense on the T2-weighted MR image (B) and the unenhanced T1-weighted MR image (C). After contrast administration (D), there was no lesion enhancement. The differential diagnosis included a high-density cystic lesion, an intrahepatic gallbladder remnant status post (subtotal) cholecystectomy or a solid tumour, and surgical resection was recommended.

Figure 2

Intraoperative images of a cystic-appearing mass (arrow) in the left liver (A) with mucoid content (B).

Question

What is the diagnosis in this male patient with non-alcoholic fatty liver disease?

Answer

A cystic liver lesion to the left of the gallbladder fossa with thick mucus content is characteristic of a ciliated hepatic foregut cyst. It is a benign lesion that originates from the migration of cells from the embryonic forgut’s dorsal bud (from which trachea and oesophagus form) into the ventral bud from which the liver develops. The lesion was completely excised, and histology revealed the typical four layers of the cyst wall (figure 3). The liver parenchyma had 60% steatosis with non-alcoholic steatohepatitis (NASH).

Figure 3

Histologically, the cyst wall has four distinguishable layers: mucus-producing epithelium with cilia (arrowheads—left panel—H&E stained), loose connective tissue, smooth muscle bundles (arrows—right panel—immunostained for smooth muscle actin) and a fibrous capsule. L indicates the cyst lumen.

A mass in a fatty liver is an increasingly prevalent clinical scenario, resulting from the frequent use of high-sensitivity imaging in an increasingly obese society. Although NASH increases the risk of hepatocellular carcinoma, which can develop without the presence of cirrhosis,1 the diagnosis of ciliated hepatic foregut cyst is rare. On imaging, its thick mucoid content results in a higher density than that of simple hepatic cysts, making it difficult to distinguish from a solid tumour. Surgical resection is recommended as squamous cell carcinoma has been reported in 5% of cases.2

The patient made an uneventful recovery. He remains in follow-up for NASH and is attempting to lose weight with a healthy diet and physical exercise.

References

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Footnotes

  • Contributors DJvdW and IAZ wrote the manuscript. GCW, AF and MAN provided the images and interpretation thereof. ST and DAG edited the manuscript. All the authors approved the final article.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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