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Ciliated hepatic foregut cyst: A rare but increasingly reported liver cyst
RADIOLOGIC-PATHOLOGIC CORRELATION
Ciliated Hepatic Foregut Cyst: A Rare but Increasingly Reported Liver Cyst Joseph D. Jakowski, BS, Joel G. Lucas, MD, Sumit Seth, MD, and Wendy L. Frankel, MD 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. Ann Diagn Pathol 8: 342-346, 2004. © 2004 Elsevier Inc. All rights reserved. Index Words: Hepatic cyst, ciliated foregut cyst
T
HE PSEUDOSTRATIFIED ciliated columnar type of hepatic cyst, termed “ciliated hepatic foregut cyst” (CHFC) by Wheeler and Edmondson,1 is a rare entity that can be a diagnostic challenge. CHFC arise from the remnants of the embryonic foregut similar to that of bronchial and esophageal cysts. To date no more than 60 cases worldwide have been reported since first described in 1857.2 Of the total numbers of reported cases, 51 have been documented since late 1980. Unlike other benign hepatic cysts, CHFC has been infrequently associated with high serologic levels of carbohydrate antigen CA19-9.3 In addition, these cysts have mimicked other lesions by appearing as a solid mass on various imaging modalities.4 Although once considered a totally benign lesion, some cases of CHFC
From the Department of Pathology, The Ohio State University, Columbus, OH. Address reprint requests to Wendy L. Frankel, MD, 401 E Doan Hall, 410 W 10th Ave, The Ohio State University, Columbus, OH 43210; E-mail: [email protected] © 2004 Elsevier Inc. All rights reserved. 1092-9134/04/0806-0000$30.00/0 doi:10.1053/j.anndiagpath.2004.08.004
342
have been recently reported to harbor squamous cell carcinoma.5–7 We present herein a case of a benign CHFC that was difficult to discriminate from a solid tumor using computed tomography (CT) and ultrasound (US). Case Report A 40-year-old black woman was initially seen at our hospital emergency department (The Ohio State University, Columbus, OH) for nausea, vomiting, and acute abdominal pain. Her past medical history was noncontributory. Physical examination demonstrated right upper quadrant and epigastric pain on palpation with guarding but no rebound tenderness or peritoneal signs. Her vital signs were normal and laboratory work-up including liver function tests were all within normal limits. An acute abdominal series was unremarkable and a right upper quadrant ultrasound showed some increased echogenicity in the liver but no discrete lesion. She was discharged from the emergency department with resolution of her symptoms but returned to the outpatient clinic 1 month later with a recurrence of symptoms. A contrast CT of the abdomen was performed and an indeterminate lesion (1.5 ⫻ 2.1 cm, 50 HU) located in segment
Annals of Diagnostic Pathology, Vol 8, No 6 (December), 2004: pp 342-346
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Figure 1. (a) Contrast-enhanced CT shows that the density content of the cyst (50 HU) is in the soft-tissue range. The cyst (solid arrow) is within segment IV of the liver and anterior to the gall bladder (broken arrow). (b) On MRI with T2-weighted spin echoimages, the cyst was hyperintense.
IVb of the medial left lobe of the liver was observed (Fig 1a). Further evaluation of the liver lesion with magnetic resonance imaging (MRI) demonstrated that it had high signal intensity on T2-weighted images (Fig lb), low signal intensity on T1-weighted images, and no ring enhancement. The patient underwent laparoscopic surgery to remove the lesion. The cyst was visualized on the anterior border of the liver and had the appearance of a miniature gallbladder. The cyst was totally resected off the liver and it was noted to contain mucinous material. An area of the liver adjacent to the resected cyst was orange in color and was biopsied. Her postoperative course was uncomplicated and she remains well.
was performed using an automated stainer with monoclonal antibodies to smooth muscle actin and chromogranin. Microscopic examination of the cyst showed that it contained the following layers: ciliated pseudostratified epithelium, subepithelial loose connective tissue, and a fibrous capsule with some areas of smooth muscle (Fig 2a, b, and c). Immunohistochemical staining supported the above microscopic findings and showed focal staining with smooth muscle actin in the wall. The epithelial cells showed scant intracytoplasmic staining with mucicarmine and a few of the other individual epithelial cells stained positively with chromogranin (Fig 2d). The liver biopsy showed mild macrovesicular fatty change.
Pathologic Findings The resected liver cyst consisted of a collapsed sac-like structure that was pink to tan and measured 1.5 ⫻ 1.1 ⫻ 0.2 cm in the collapsed state. The internal and external surfaces were smooth. A cut section showed no intramural abnormality of the cyst and it had a wall thickness of 0.1 cm. The entire specimen was routinely processed and the paraffinembedded sections were stained with hematoxylineosin. Additional sections were stained with mucicarmine and trichrome. Immunohistochemistry
Discussion Hepatic cysts occur in approximately 5% of the general population.8 The differential diagnosis of a hepatic cyst may be broadly categorized as infectious and noninfectious (Fig 3). The noninfectious cysts include both neoplastic and nonneoplastic cysts. Neoplastic cysts are usually characterized by their large size and many are multilocular. Nonneoplastic cysts are usually small, unilocular, and asymptomatic. Histologically, hepatic cysts can have
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Figure 2. Photomicrographs of the wall of the ciliated hepatic foregut cyst. (a) Scanning power demonstrates the layers of the cyst (1), psuedostratified columnar epithelium with subepithelial loose connective tissue; (2), smooth muscle layer; and (3), outer fibrous capsule. (b) Low power shows pseudostratified columnar epithelium overlying a fibrous and smooth muscle layer. (c) High power shows ciliated pseudostratified columnar epithelium. (d) High power shows that the Clara cells scattered in the epithelium stain positive with chromogranin.
a squamous, cuboidal, or columnar epithelium lining or they may have no identifiable epithelium (pseudocyst). Clinically and radiographically, however, it is sometimes difficult to distinguish between the neoplastic and nonneoplastic hepatic cysts based on the size, density, number of septations of the cyst, or from the symptoms of the patient. The distinction is necessary to provide proper treatment
to the patient and for prognostic purposes. Treatment for the different hepatic cysts can range from medical observation for small simple cysts to surgical resection for neoplastic ones.8 CHFC is a rare epithelial lined cyst with about 60 cases reported since the mid 19th century.9 –11 Although there is a bimodal distribution to the number of cases reported over the last century and a
Ciliated Hepatic Foregut Cyst
Figure 3. The differential diagnosis of a hepatic cyst. * Included are cystic lesions not considered true cysts.
half, the majority of CHFC cases have been reported in the last 20 years (Fig 4). It has been suggested that the peak in CHFC cases in the mid-to-late 19th century occurred at a time when autopsies were performed more frequently.10 Many others have suggested that the more dramatic increase in reported cases over the last two decades coincides with the increased use of abdominal imaging techniques (eg, US, MRI, and CT). 10,11 This view assumes that the prevalence of the cysts has not changed over time. Patients with a CHFC are usually asymptomatic and the lesion is found incidentally during abdominal imaging studies, surgical exploration, or at postmortem examination. A minority, like our patient, can present with right upper quadrant pain and nausea or vomiting. There has also been a rare report of portal vein compression secondary to mass effect from the cyst.12 CHFC is usually localized in the left lobe of the liver in segment IV, but several right lobe cysts have also been described.11 The cysts are usually unilocular, subcapsular, and less than 5 cm in size. About two thirds of the CHFC imaged with CT and US have typical cyst-like features that include a hypoechoic area and well defined wall on US, and a hypodense area without enhancement after contrast with CT.11 Our case falls into the remaining one third of the reported CHFC imaged that have a solid tumor appearance on CT and a non-cystic appearance on US. The atypical radiologic features of CHFC can lead to the impression of a hepatobiliary cystadenoma or cys-
345
tadenocarcinoma.3 The most reasonable explanation for a solid appearance on imaging studies is mucinous material of varying density together with calcium and cholesterol crystals within the cyst.3,4,11 Serologic levels of CA19-9 have been of no clinical use in discriminating between CHFC and the malignant cysts because high levels have also been found in benign CHFC.3 The CHFC has been classically described as having four layers: ciliated pseudostratified epithelium with mucus cells, subepithelial loose connective tissue, smooth muscle layer, and an outer fibrous capsule.11 Positive staining with chromogranin of some of the epithelial cells, as in our case and in other cases of CHFC strongly suggest the presence of Clara cells.13 The overall cellular features and architecture are similar to those of the respiratory bronchus and indicate that these cysts arise from abnormally developing ventral endoderm within the liver.1,5,13,14 Mouse embryo studies have demonstrated that the ventral endoderm gives rise to the adult foregut structures, including the oropharynx down to the hepatic diverticulum.15 Subsequent differentiation and budding of tissue along the foregut gives rise to the thyroid, lung, liver, and the ventral pancreatic structures.15 Given the common origin of the respiratory system and other foregut derivatives, it is not surprising that ciliated foregut cysts have been reported in numerous other places in addition to the liver, including the sublingual area,16 esophagus,17,18 stomach,19 and pancreas.20 Until 1999, all reported CHFC had benign morphologic features. Since that time at least three
Figure 4. The number of case reports of CHFC compared with the trends in use of CT, MRI, and US over the same time interval (years).2, 7, 9 –11, 21
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cases of malignant transformation have been reported.5–7 Overall, this corresponds with a 4% to 5% rate of malignancy in the CHFC cases reported thus far. The major risk factor for malignant transformation appears to be the size of the cyst. All the reported cases of malignancy occurred in cysts greater than 12 cm. However, none of these malignant cysts have been reported to metastasize or to recur after excision. Most now agree that total surgical excision of the cyst is necessary in patients who have: a cyst greater than 4 to 5 cm, a symptomatic cyst, an enlarging cyst, or when imaging studies show abnormalities in the cyst wall.5–7 Vick et al,5 however, recommend surgical excision even for asymptomatic patients. In conclusion, we present a rare case of a ciliated foregut cyst of the liver. Our case showed the typical benign morphology and usual location within the liver. The symptomatic presentation of our patient, together with the solid mass appearance of the cyst on CT and the anechoic findings on US, however, make our case unique compared with the majority of other reported cases. Because CHFC have a potential for malignant transformation and can be confused radiologically with other entities, surgical resection and pathologic examination is necessary in many cases to exclude a neoplastic lesion. In addition, because of the varied internal appearance of some CHFC, it must be included in the differential diagnosis for a hypovascular solid tumor of the liver. References 1. Wheeler DA, Edmunson HA: Ciliated hepatic foregut cyst. Am J Surg Pathol 1984;8:467-470 2. Friedreich N: Cyste mit Flimmerepithel in der Leber. Arch Pathol Anat 1857;11:466-469 3. Wu ML, Abecassis MM, Rao MS: Ciliated hepatic foregut cyst mimicking neoplasm. Am J Gastroenterol 1998;93:22122214 4. Kadoya M, Matsui O, Nakanuma Y, et al: Ciliated hepatic foregut cyst: Radiologic features. Radiology 1990;175:475-477 5. Vick DJ, Goodman ZD, Ishak KG: Squamous cell carci-
noma arising in a ciliated hepatic foregut cyst. Arch Pathol Lab Med 1999;123:1115-1117 6. Furlanetto A, Dei Tos AP: Squamous cell carcinoma arising in a ciliated hepatic foregut cyst. Virchows Arch 2002;441: 296-298 7. de Lajarte-Thirouard AS, Rioux-Leclercq N, Boudjema K, et al: Squamous cell carcinoma arising in a ciliated hepatic forgut cyst. Pathol Res Pract 2002;198:697-700 8. Hansman MF, Ryan JA, Holmes JH, et al: Management and long-term follow-up of hepatic cysts. Am J Surgery 2001;181: 404-410 9. Balducci G, Bellagamba R, De Siena T, et al: [Ciliated hepatic foregut cysts: A case report]. G Chir 2003;24:189-192 10. Vick DJ, Goodman ZD, Deavers MT, et al: Ciliated hepatic foregut cyst: A study of six cases and review of the literature. Am J Surg Path 1999;23:671-677 11. Takahiro H, Masaharu O, Takashi M, et al: Ciliated hepatic foregut cyst: A report of one case and a review of the literature. Hepatology Research 2003;26:243-248 12. Harty MP, Hebra A, Ruchelli ED, et al: Ciliated hepatic foregut cyst causing portal hypertension in an adolescent. AJR Am J Roentgenol 1998;170:688-690 13. Terada T, Nakanuma Y, Kono N, et al: Ciliated hepatic foregut cyst. A mucus histochemical immunohistochemical and ultrastructural study in three cases in comparison with normal bronchi and intrahepatic bile ducts. Am J Surg Path 1990;14:356-363 14. Chatelain D, Chailley-Heu B, Terris B, et al: The ciliated hepatic foregut cyst, an unusual bronchiolar foregut malformation: A histological, histochemical, and immunohistochemical study of 7 cases. Human Pathol 2000;31:241-246 15. Zaret KS: Regulatory phases of early liver development: Paradigms of organogenesis. Nat Rev Genet 2002;3:499-512 16. Kim YS, Ann SK, Lee SH: Sublingual foregut cyst. J Dermatol 1998;25:476-478 17. Raeburn C: Columnar ciliated epithelium in the adult oesophagus. J Pathol Bact 1951;63:157-158 18. Lee MY, Jensen E, Kwak S, et al: Metastatic adenocarcinoma arising in a congenital foregut cyst of the esophagus. Am J Clin Oncol 1998;21:64-66 19. Gensler S, Seidenberg B, Rifkin H, et al: Ciliated lined intramural cyst of the stomach: Case report and suggested embryogenesis. Ann Surg 1966;163:954-956 20. Munshi IA, Parra-Davila E, Casillas VJ, et al: Cilliated foregut cyst of the pancreas. HPB Surg 1998;11:117-119 21. Sources and Effects of Ionizing Radiation. United Nations Scientific Committee on the Effect of Atomic Radiation UNSCEAR Report to the General Assembly, with Scientific Annexes. United Nations, New York, NY, 2000; Annex D, pp 304-314
Ciliated Hepatic Foregut Cyst: A Rare but Increasingly Reported Liver Cyst Joseph D. Jakowski, BS, Joel G. Lucas, MD, Sumit Seth, MD, and Wendy L. Frankel, MD 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. Ann Diagn Pathol 8: 342-346, 2004. © 2004 Elsevier Inc. All rights reserved. Index Words: Hepatic cyst, ciliated foregut cyst
T
HE PSEUDOSTRATIFIED ciliated columnar type of hepatic cyst, termed “ciliated hepatic foregut cyst” (CHFC) by Wheeler and Edmondson,1 is a rare entity that can be a diagnostic challenge. CHFC arise from the remnants of the embryonic foregut similar to that of bronchial and esophageal cysts. To date no more than 60 cases worldwide have been reported since first described in 1857.2 Of the total numbers of reported cases, 51 have been documented since late 1980. Unlike other benign hepatic cysts, CHFC has been infrequently associated with high serologic levels of carbohydrate antigen CA19-9.3 In addition, these cysts have mimicked other lesions by appearing as a solid mass on various imaging modalities.4 Although once considered a totally benign lesion, some cases of CHFC
From the Department of Pathology, The Ohio State University, Columbus, OH. Address reprint requests to Wendy L. Frankel, MD, 401 E Doan Hall, 410 W 10th Ave, The Ohio State University, Columbus, OH 43210; E-mail: [email protected] © 2004 Elsevier Inc. All rights reserved. 1092-9134/04/0806-0000$30.00/0 doi:10.1053/j.anndiagpath.2004.08.004
342
have been recently reported to harbor squamous cell carcinoma.5–7 We present herein a case of a benign CHFC that was difficult to discriminate from a solid tumor using computed tomography (CT) and ultrasound (US). Case Report A 40-year-old black woman was initially seen at our hospital emergency department (The Ohio State University, Columbus, OH) for nausea, vomiting, and acute abdominal pain. Her past medical history was noncontributory. Physical examination demonstrated right upper quadrant and epigastric pain on palpation with guarding but no rebound tenderness or peritoneal signs. Her vital signs were normal and laboratory work-up including liver function tests were all within normal limits. An acute abdominal series was unremarkable and a right upper quadrant ultrasound showed some increased echogenicity in the liver but no discrete lesion. She was discharged from the emergency department with resolution of her symptoms but returned to the outpatient clinic 1 month later with a recurrence of symptoms. A contrast CT of the abdomen was performed and an indeterminate lesion (1.5 ⫻ 2.1 cm, 50 HU) located in segment
Annals of Diagnostic Pathology, Vol 8, No 6 (December), 2004: pp 342-346
Ciliated Hepatic Foregut Cyst
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Figure 1. (a) Contrast-enhanced CT shows that the density content of the cyst (50 HU) is in the soft-tissue range. The cyst (solid arrow) is within segment IV of the liver and anterior to the gall bladder (broken arrow). (b) On MRI with T2-weighted spin echoimages, the cyst was hyperintense.
IVb of the medial left lobe of the liver was observed (Fig 1a). Further evaluation of the liver lesion with magnetic resonance imaging (MRI) demonstrated that it had high signal intensity on T2-weighted images (Fig lb), low signal intensity on T1-weighted images, and no ring enhancement. The patient underwent laparoscopic surgery to remove the lesion. The cyst was visualized on the anterior border of the liver and had the appearance of a miniature gallbladder. The cyst was totally resected off the liver and it was noted to contain mucinous material. An area of the liver adjacent to the resected cyst was orange in color and was biopsied. Her postoperative course was uncomplicated and she remains well.
was performed using an automated stainer with monoclonal antibodies to smooth muscle actin and chromogranin. Microscopic examination of the cyst showed that it contained the following layers: ciliated pseudostratified epithelium, subepithelial loose connective tissue, and a fibrous capsule with some areas of smooth muscle (Fig 2a, b, and c). Immunohistochemical staining supported the above microscopic findings and showed focal staining with smooth muscle actin in the wall. The epithelial cells showed scant intracytoplasmic staining with mucicarmine and a few of the other individual epithelial cells stained positively with chromogranin (Fig 2d). The liver biopsy showed mild macrovesicular fatty change.
Pathologic Findings The resected liver cyst consisted of a collapsed sac-like structure that was pink to tan and measured 1.5 ⫻ 1.1 ⫻ 0.2 cm in the collapsed state. The internal and external surfaces were smooth. A cut section showed no intramural abnormality of the cyst and it had a wall thickness of 0.1 cm. The entire specimen was routinely processed and the paraffinembedded sections were stained with hematoxylineosin. Additional sections were stained with mucicarmine and trichrome. Immunohistochemistry
Discussion Hepatic cysts occur in approximately 5% of the general population.8 The differential diagnosis of a hepatic cyst may be broadly categorized as infectious and noninfectious (Fig 3). The noninfectious cysts include both neoplastic and nonneoplastic cysts. Neoplastic cysts are usually characterized by their large size and many are multilocular. Nonneoplastic cysts are usually small, unilocular, and asymptomatic. Histologically, hepatic cysts can have
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Figure 2. Photomicrographs of the wall of the ciliated hepatic foregut cyst. (a) Scanning power demonstrates the layers of the cyst (1), psuedostratified columnar epithelium with subepithelial loose connective tissue; (2), smooth muscle layer; and (3), outer fibrous capsule. (b) Low power shows pseudostratified columnar epithelium overlying a fibrous and smooth muscle layer. (c) High power shows ciliated pseudostratified columnar epithelium. (d) High power shows that the Clara cells scattered in the epithelium stain positive with chromogranin.
a squamous, cuboidal, or columnar epithelium lining or they may have no identifiable epithelium (pseudocyst). Clinically and radiographically, however, it is sometimes difficult to distinguish between the neoplastic and nonneoplastic hepatic cysts based on the size, density, number of septations of the cyst, or from the symptoms of the patient. The distinction is necessary to provide proper treatment
to the patient and for prognostic purposes. Treatment for the different hepatic cysts can range from medical observation for small simple cysts to surgical resection for neoplastic ones.8 CHFC is a rare epithelial lined cyst with about 60 cases reported since the mid 19th century.9 –11 Although there is a bimodal distribution to the number of cases reported over the last century and a
Ciliated Hepatic Foregut Cyst
Figure 3. The differential diagnosis of a hepatic cyst. * Included are cystic lesions not considered true cysts.
half, the majority of CHFC cases have been reported in the last 20 years (Fig 4). It has been suggested that the peak in CHFC cases in the mid-to-late 19th century occurred at a time when autopsies were performed more frequently.10 Many others have suggested that the more dramatic increase in reported cases over the last two decades coincides with the increased use of abdominal imaging techniques (eg, US, MRI, and CT). 10,11 This view assumes that the prevalence of the cysts has not changed over time. Patients with a CHFC are usually asymptomatic and the lesion is found incidentally during abdominal imaging studies, surgical exploration, or at postmortem examination. A minority, like our patient, can present with right upper quadrant pain and nausea or vomiting. There has also been a rare report of portal vein compression secondary to mass effect from the cyst.12 CHFC is usually localized in the left lobe of the liver in segment IV, but several right lobe cysts have also been described.11 The cysts are usually unilocular, subcapsular, and less than 5 cm in size. About two thirds of the CHFC imaged with CT and US have typical cyst-like features that include a hypoechoic area and well defined wall on US, and a hypodense area without enhancement after contrast with CT.11 Our case falls into the remaining one third of the reported CHFC imaged that have a solid tumor appearance on CT and a non-cystic appearance on US. The atypical radiologic features of CHFC can lead to the impression of a hepatobiliary cystadenoma or cys-
345
tadenocarcinoma.3 The most reasonable explanation for a solid appearance on imaging studies is mucinous material of varying density together with calcium and cholesterol crystals within the cyst.3,4,11 Serologic levels of CA19-9 have been of no clinical use in discriminating between CHFC and the malignant cysts because high levels have also been found in benign CHFC.3 The CHFC has been classically described as having four layers: ciliated pseudostratified epithelium with mucus cells, subepithelial loose connective tissue, smooth muscle layer, and an outer fibrous capsule.11 Positive staining with chromogranin of some of the epithelial cells, as in our case and in other cases of CHFC strongly suggest the presence of Clara cells.13 The overall cellular features and architecture are similar to those of the respiratory bronchus and indicate that these cysts arise from abnormally developing ventral endoderm within the liver.1,5,13,14 Mouse embryo studies have demonstrated that the ventral endoderm gives rise to the adult foregut structures, including the oropharynx down to the hepatic diverticulum.15 Subsequent differentiation and budding of tissue along the foregut gives rise to the thyroid, lung, liver, and the ventral pancreatic structures.15 Given the common origin of the respiratory system and other foregut derivatives, it is not surprising that ciliated foregut cysts have been reported in numerous other places in addition to the liver, including the sublingual area,16 esophagus,17,18 stomach,19 and pancreas.20 Until 1999, all reported CHFC had benign morphologic features. Since that time at least three
Figure 4. The number of case reports of CHFC compared with the trends in use of CT, MRI, and US over the same time interval (years).2, 7, 9 –11, 21
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cases of malignant transformation have been reported.5–7 Overall, this corresponds with a 4% to 5% rate of malignancy in the CHFC cases reported thus far. The major risk factor for malignant transformation appears to be the size of the cyst. All the reported cases of malignancy occurred in cysts greater than 12 cm. However, none of these malignant cysts have been reported to metastasize or to recur after excision. Most now agree that total surgical excision of the cyst is necessary in patients who have: a cyst greater than 4 to 5 cm, a symptomatic cyst, an enlarging cyst, or when imaging studies show abnormalities in the cyst wall.5–7 Vick et al,5 however, recommend surgical excision even for asymptomatic patients. In conclusion, we present a rare case of a ciliated foregut cyst of the liver. Our case showed the typical benign morphology and usual location within the liver. The symptomatic presentation of our patient, together with the solid mass appearance of the cyst on CT and the anechoic findings on US, however, make our case unique compared with the majority of other reported cases. Because CHFC have a potential for malignant transformation and can be confused radiologically with other entities, surgical resection and pathologic examination is necessary in many cases to exclude a neoplastic lesion. In addition, because of the varied internal appearance of some CHFC, it must be included in the differential diagnosis for a hypovascular solid tumor of the liver. References 1. Wheeler DA, Edmunson HA: Ciliated hepatic foregut cyst. Am J Surg Pathol 1984;8:467-470 2. Friedreich N: Cyste mit Flimmerepithel in der Leber. Arch Pathol Anat 1857;11:466-469 3. Wu ML, Abecassis MM, Rao MS: Ciliated hepatic foregut cyst mimicking neoplasm. Am J Gastroenterol 1998;93:22122214 4. Kadoya M, Matsui O, Nakanuma Y, et al: Ciliated hepatic foregut cyst: Radiologic features. Radiology 1990;175:475-477 5. Vick DJ, Goodman ZD, Ishak KG: Squamous cell carci-
noma arising in a ciliated hepatic foregut cyst. Arch Pathol Lab Med 1999;123:1115-1117 6. Furlanetto A, Dei Tos AP: Squamous cell carcinoma arising in a ciliated hepatic foregut cyst. Virchows Arch 2002;441: 296-298 7. de Lajarte-Thirouard AS, Rioux-Leclercq N, Boudjema K, et al: Squamous cell carcinoma arising in a ciliated hepatic forgut cyst. Pathol Res Pract 2002;198:697-700 8. Hansman MF, Ryan JA, Holmes JH, et al: Management and long-term follow-up of hepatic cysts. Am J Surgery 2001;181: 404-410 9. Balducci G, Bellagamba R, De Siena T, et al: [Ciliated hepatic foregut cysts: A case report]. G Chir 2003;24:189-192 10. Vick DJ, Goodman ZD, Deavers MT, et al: Ciliated hepatic foregut cyst: A study of six cases and review of the literature. Am J Surg Path 1999;23:671-677 11. Takahiro H, Masaharu O, Takashi M, et al: Ciliated hepatic foregut cyst: A report of one case and a review of the literature. Hepatology Research 2003;26:243-248 12. Harty MP, Hebra A, Ruchelli ED, et al: Ciliated hepatic foregut cyst causing portal hypertension in an adolescent. AJR Am J Roentgenol 1998;170:688-690 13. Terada T, Nakanuma Y, Kono N, et al: Ciliated hepatic foregut cyst. A mucus histochemical immunohistochemical and ultrastructural study in three cases in comparison with normal bronchi and intrahepatic bile ducts. Am J Surg Path 1990;14:356-363 14. Chatelain D, Chailley-Heu B, Terris B, et al: The ciliated hepatic foregut cyst, an unusual bronchiolar foregut malformation: A histological, histochemical, and immunohistochemical study of 7 cases. Human Pathol 2000;31:241-246 15. Zaret KS: Regulatory phases of early liver development: Paradigms of organogenesis. Nat Rev Genet 2002;3:499-512 16. Kim YS, Ann SK, Lee SH: Sublingual foregut cyst. J Dermatol 1998;25:476-478 17. Raeburn C: Columnar ciliated epithelium in the adult oesophagus. J Pathol Bact 1951;63:157-158 18. Lee MY, Jensen E, Kwak S, et al: Metastatic adenocarcinoma arising in a congenital foregut cyst of the esophagus. Am J Clin Oncol 1998;21:64-66 19. Gensler S, Seidenberg B, Rifkin H, et al: Ciliated lined intramural cyst of the stomach: Case report and suggested embryogenesis. Ann Surg 1966;163:954-956 20. Munshi IA, Parra-Davila E, Casillas VJ, et al: Cilliated foregut cyst of the pancreas. HPB Surg 1998;11:117-119 21. Sources and Effects of Ionizing Radiation. United Nations Scientific Committee on the Effect of Atomic Radiation UNSCEAR Report to the General Assembly, with Scientific Annexes. United Nations, New York, NY, 2000; Annex D, pp 304-314