Ciliated foregut cyst of the pancreas

Ciliated foregut cysts involving the hepatopancreaticobiliary system: a clinicopathological evaluation with focus on atypical features

AIMS

Foregut cystic malformations are rare developmental abnormalities, which may involve the hepatopancreaticobiliary tract (HPBT). These cysts are composed of inner ciliated epithelium; subepithelial connective tissue layer; smooth muscle layer; and an outer fibrous layer. While radiopathologic findings are often diagnostic, atypical location and histologic features can pose a diagnostic challenge. We aimed to study ciliated foregut cysts (CFCs) in the HPBT, assess their clinicopathological features with a focus on atypical features.

METHODS

We collected cases of CFCs involving the HPBT from three large academic medical centres. H&E-stained slides and immunohistochemical stains (where available) were reviewed for each case. Relevant demographic, clinical and pathological information was collected from the medical records.

RESULTS

21 cases were identified. The median age was 53 years (range, 3-78 years). 17 cysts were identified within the liver (segment 4 was the most common location, n=10) and 4 in the pancreas. Cysts were mostly identified incidentally (n=13), abdominal pain was a common symptom (n=5). Cyst size ranged from 0.7 to 17.0 cm (median, 2.5 cm). Radiological findings were available in 17 cases. Cilia were identified in all cases. 19 of 21 cases demonstrated the presence of a smooth muscle layer (thickness, <0.1 mm to 3.0 mm). Three cases showed gastric metaplasia, while one case revealed additional low-grade dysplasia, with features similar to intraductal papillary neoplasm of the bile duct.

CONCLUSIONS

We highlight clinicopathological features of CFCs in the HPBT. The histomorphology is usually straightforward; however, unusual location and atypical features can pose a diagnostic challenge.

Pancreatic cysts: pathologic classification, differential diagnosis, and clinical implications

CONTEXT

Cystic lesions of the pancreas are being recognized with increasing frequency and have become a more common finding in clinical practice because of the widespread use of advanced imaging modalities and the sharp drop in the mortality rate of pancreatic surgery. Consequently, in the past 2 decades, the nature of many cystic tumors in this organ has been better characterized, and significant developments have taken place in the classification and in our understanding of pancreatic cystic lesions.

OBJECTIVE

To provide an overview of the current concepts in classification, differential diagnosis, and clinical/biologic behavior of pancreatic cystic tumors.

DATA SOURCES

The authors' personal experience, based on institutional and consultation materials, combined with an analysis of the literature.

CONCLUSIONS

In contrast to solid tumors, most of which are invasive ductal adenocarcinomas with dismal prognosis, cystic lesions of the pancreas are often either benign or low-grade indolent neoplasia. However, those that are mucinous, namely, intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, constitute an important category because they have well-established malignant potential, representing an adenoma-carcinoma sequence. Those that are nonmucinous such as serous tumors, congenital cysts, lymphoepithelial cysts, and squamoid cyst of pancreatic ducts have no malignant potential. Only rare nonmucinous cystic tumors that occur as a result of degenerative/necrotic changes in otherwise solid neoplasia, such as cystic ductal adenocarcinomas, cystic pancreatic endocrine neoplasia, and solid-pseudopapillary neoplasm, are also malignant and have variable degrees of aggressiveness.

Ciliated foregut cyst of pancreas: cytologic findings on endoscopic ultrasound-guided fine-needle aspiration

The cytologic findings of a ciliated foregut cyst of the pancreas diagnosed by endoscopic ultrasound-guided fine-needle aspiration (FNA) are described. Cytologic features of ciliated foregut cysts include the presence of ciliated columnar cells and detached ciliary tufts in a cystic fluid background with amorphous debris and rare macrophages. These cytologic findings are clearly distinct from those of cystic mucinous neoplasms and other pancreatic cysts with which the ciliated foregut cyst may be confused. To the best of our knowledge, this is the first case reporting the cytologic findings of a pancreatic ciliated foregut cyst sampled by endoscopic ultrasound-guided FNA. We believe that the distinctive and characteristic cytologic features can allow a preoperative cytologic diagnosis of this highly unusual pancreatic cystic lesion.

Cystic lesions of the pancreas

Although cystic tumors of the pancreas are relatively rare, they constitute an increasingly important category. Advances in imaging and interventional techniques and the sharp drop in the mortality rate of pancreatic surgery have rendered pancreatic biopsies and resections commonplace specimens. Consequently, in the past two decades, the nature of many cystic tumors in this organ has been better characterized. The names of some existing entities were revised; for example, what was known as papillary-cystic tumor is now regarded as solid-pseudopapillary tumor. New entities, in particular, intraductal papillary mucinous neoplasm and its variants, such as oncocytic and intestinal subtypes were recognized. The importance of clinical and pathologic correlation in the evaluation of these lesions was appreciated, in particular, with regards to the multifocality of these lesions, their association with invasive carcinomas, and thus their 'preinvasive' nature. Consensus criteria for the distinction of these from the ordinary precursors of adenocarcinoma, the pancreatic intraepithelial neoplasia, were established. The definition of mucinous cystic neoplasms was refined; ovarian-like stroma has now become almost a requirement for the diagnosis of mucinous cystic neoplasia, and defined as such, the propensity of these tumors to occur in perimenopausal women became even more striking. The validity and clinical value of classifying the pancreatic cysts of mucinous type as adenoma, borderline, CIS and invasive have been established. Related to this, the importance of thorough sampling in accurate classification of these mucinous lesions was recognized. Greater accessibility of the pancreas afforded by improved invasive as well as noninvasive modalities has also increased the detection of otherwise clinically silent cystic tumors, which has led to the recognition of more innocuous entities such as acinar cell cystadenoma and squamoid cyst of pancreatic ducts. As the significance of the cystic lesions emerged, cystic forms of otherwise typically solid tumors were also better characterized. Thus, significant developments have taken place in the classification and our understanding of pancreatic cystic tumors in the past few years, and experience with these lesions is likely to grow exponentially in the coming years.

Ciliated hepatic foregut cyst with extensive squamous metaplasia: report of a case

Ciliated hepatic foregut cysts (CHFC) are rare cystic lesions of the liver composed of a ciliated pseudostratified columnar epithelium with mucous cells, connective tissue, and smooth muscles bundles. We report the first case of CHFC with extensive squamous metaplasia without dysplasia or carcinoma. A unilocular, avascular, hypoechoic 60-mm liver lesion located in segment IV was detected by ultrasonography in a 31-year-old woman. The cyst was surgically removed and was lined mainly by a regular squamous epithelium without keratin formation. After extensive sampling, a ciliated pseudostratified columnar epithelium with some alcian blue-positive goblet cells was identified. The lesion was totally examined and there was no epithelial dysplasia or carcinoma. Squamous epithelium is very rare in hepatic foregut cysts and may degenerate into squamous carcinoma. Squamous epithelium is also described in biliary cysts. When squamous epithelium is identified in a liver cyst, an extensive sampling is recommended to identify possible foci of squamous carcinoma and to classify more precisely the histological type of the lesion. Because some cases of squamous carcinoma have been described in CHFC, surgical removal of the lesion may be more appropriate than close follow-up or sclerosing therapy.

Ciliated hepatic foregut cyst: A rare but increasingly reported liver cyst

We report a case of a ciliated hepatic foregut cyst (CHFC) in the left lobe of the liver in a 42-year-old woman. To date, only 60 cases of these respiratory epithelial lined hepatic cysts have been reported since first described by Friedrich in 1857. CHFC are believed to be congenitally derived from the embryonic foregut and are considered benign lesions that are most often unilocular. Recently, however, there has been documented malignant transformation in these cysts. The majority of patients with a CHFC are asymptomatic and the cyst is usually an incidental finding during abdominal imaging studies or during surgical exploration. Interestingly, 85% of the total number of cases of CHFC have been reported within the last two decades. This recent rise in case reports is likely explained by greater detection because of the dramatic rise in the use of abdominal imaging. In our case, however, ultrasound failed to demonstrate any lesion within the liver and on computed tomography the cyst was more consistent with a soft tissue mass. Therefore, pathologic evaluation was necessary for the correct diagnosis of this liver lesion and to exclude malignancy.

Cysts and tumors of the pancreas

Both pancreatic cysts and pancreatic tumors rarely occur in childhood. However, when encountered they can present a diagnostic and therapeutic challenge to the pediatric surgeon. The aim of this review is to discuss the different types of pancreatic cysts and tumours that may be encountered in the pediatric population, to note the modes available for their diagnosis, and to outline treatment options.

Ciliated foregut cyst of the gallbladder: a case report and review of the literature

A case is presented of a ciliated cyst of the gallbladder in a 36-year-old Korean woman which was incidentally found on ultrasonographic study. A cystic mass measuring 1.5 x 1 x 1 cm was found in the fundus of the gallbladder. The cyst was unilocular and intramural without communication to the lumen. Microscopically, the cyst wall was lined by a single layer of pseudostratified, ciliated, columnar epithelium and goblet cells with underlying smooth muscle layers. This was considered to be the cyst arising from the embryonic foregut and showing differentiation toward respiratory structures. The term 'ciliated foregut cyst of the gallbladder' is suggested here.