The diagnosis
Answer: Hepatic foregut duplication cyst and concurrent acute gangrenous cholecystitis
Our patient underwent operative intervention for cholecystitis; the surgical specimen showed acute cholecystitis with necrosis. Surgical enucleation of the unilocular cyst was also performed. No communication to the gallbladder was identified. Histologically, three distinct layers were noted (mucosa, submucosa, and muscularis propria), consistent with a foregut duplication cyst (Figure C). The muscularis propria contained a rudimentary myenteric plexus, including ganglion cells, identified on S100 staining (Figure D, upper right; higher power, Figure E). The cyst was lined by multilayered cuboidal epithelium with cilia, beneath which there were scattered, nondescript glands.
Two examples of foregut duplication cyst within the liver have been described in the literature, one representing duplicated duodenum1 and one ileum.2 The classic histologic features of foregut duplications include 1) well-developed smooth muscle layers, including muscularis mucosa and muscularis propria, 2) an epithelial lining that may be gastric, intestinal, or respiratory type, and 3) contiguity to the foregut segment that is duplicated.
Our differential diagnosis also included ciliated hepatic foregut cyst; however, that entity should have ciliated epithelium surrounded by disorganized bundles of smooth muscle and a dense fibrous outer capsule.3 The imaging findings also raised consideration of other possible etiologies, including intrahepatic biliary mucinous cystadenoma, gallbladder duplication, and type II choledochal cyst. Typical findings of these lesions were not identified. Malignancy has reportedly arisen from all of these various lesions; therefore, surgical excision was indicated given the concern over etiology.
References
1. Imamoglu K.H., Walt, A.J. Duplication of the duodenum extending into liver. Am J Surg. 1977;133:628-32.
2. Seidman J.D., Yale-Loehr A.J., Beaver B., et al. Alimentary duplication presenting as an hepatic cyst in a neonate. Am J Surg Pathol. 1991;15:695-8.
3. Vick D.J., Goodman Z.D., Deavers M.T., et al. Ciliated hepatic foregut cyst: A study of six cases and review of the literature. Am J Surg Pathol. 1999;23:671-7.
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