This is an uncommon benign tumor of the liver that may be mistaken for a malignancy.The pathologists plays a critical role in making the tissue diagnosis.
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| RADIOLOGIC |
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Focal nodular hyperplasia: findings at state-of-the-art MR imaging, US, CT, and pathologic analysis.
Hussain SM, Terkivatan T, Zondervan PE, Lanjouw E, de Rave S, Ijzermans JN, de Man RA.
Department of Radiology, Erasmus Medical Center, Dr Molewaterplein 40, 3015 GD Rotterdam, the Netherlands.
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| Radiographics. 2004 Jan-Feb;24(1):3-17; discussion 18-9. Abstract quote |
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Focal nodular hyperplasia (FNH) is the second most common benign liver tumor after hemangioma. FNH is classified into two types: classic (80% of cases) and nonclassic (20%). Distinction between FNH and other hypervascular liver lesions such as hepatocellular adenoma, hepatocellular carcinoma, and hypervascular metastases is critical to ensure proper treatment.
An asymptomatic patient with FNH does not require biopsy or surgery. Magnetic resonance (MR) imaging has higher sensitivity and specificity for FNH than does ultrasonography or computed tomography.
Typically, FNH is iso- or hypointense on T1-weighted images, is slightly hyper- or isointense on T2-weighted images, and has a hyperintense central scar on T2-weighted images. FNH demonstrates intense homogeneous enhancement during the arterial phase of gadolinium-enhanced imaging and enhancement of the central scar during later phases. Familiarity with the proper MR imaging technique and the spectrum of MR imaging findings is essential for correct diagnosis of FNH.
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Radiological features of focal nodular hyperplasia of the liver in children.
Cheon JE, Kim WS, Kim IO, Jang JJ, Seo JK, Yeon KM.
Department of Radiology and the Institute of Radiation Medicine, College of Medicine, Seoul National University, Seoul, Korea.
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BACKGROUND: Focal nodular hyperplasia (FNH) is an unusual hepatic tumour in children and should be distinguished from other hepatic lesions.
OBJECTIVE: To describe the imaging characteristics of FNH in children.
MATERIALS AND METHODS: We examined five patients (three boys and two girls, mean age 9.4 years) with pathologically confirmed FNH. The diagnosis was obtained by tumour resection (n = 4) and percutaneous needle biopsy (n = 1). One patient with multiple FNHs showed recurrent lesions after tumour resection. All patients were studied with US (including colour and power Doppler US [n = 3]) and CT. Dynamic enhanced CT scans were available in three patients. MRI (n = 2) or coeliac angiography (n = 1) was performed in three patients.
RESULTS: Seven of eight FNH lesions in five patients were demonstrated by imaging. The average size of the lesions was 6.5 cm. Six lesions detected on US showed variable echogenicity with a central hyperechoic scar (n = 2). On Doppler examination, central or peripheral hypervascular areas were seen (n = 3). Six lesions detected on contrast-enhanced CT showed high attenuation (n = 4) or iso-attenuation (n = 2). On early phase scans, all the lesions (n = 3) showed high attenuation. Irregular linear or ovoid central scars were detected in two patients on CT. MR demonstrated three lesions in two patients, one of which had not been detected by US or CT. A central low signal intensity scar (n = 1) was seen on T2-weighted MRI. Coeliac angiography performed in one patient showed a hypervascular mass with homogeneous staining.
CONCLUSION: FNH in children shows a wide spectrum of imaging findings on various radiological examinations and the typical central scar was not always seen on imaging studies. Dynamic enhanced CT obtained in the early phase and colour Doppler studies may be helpful in the diagnosis of FNH by allowing characterisation of tumour vascularity. FNH should be included in the differential diagnosis of liver mass in children.
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Focal nodular hyperplasia of the liver: radiologic-pathologic correlation.
Buetow PC, Pantongrag-Brown L, Buck JL, Ros PR, Goodman ZD.
Department of Radiologic Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
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Focal nodular hyperplasia (FNH) is a benign hepatic tumor that likely represents a local hyperplastic response of hepatocytes to a congenital vascular anomaly. It is most commonly seen in middle-aged women and is typically a solid mass measuring less than 5 cm in diameter.
Most lesions have central scars that contain thick-walled vessels that provide excellent arterial blood supply; hemorrhage, necrosis, and infarction are, therefore, extremely unusual. Characteristic imaging features include a hypervascular homogeneous tumor with a central scar and with both hepatocellular and reticuloendothelial function. Ultrasonography, computed tomography, scintigraphy, and magnetic resonance imaging all offer different advantages in the detection and characterization of FNH.
There is excellent correlation between the pathologic and imaging features of FNH. In many cases, it is possible to obtain a prospective imaging diagnosis of FNH; however, in some cases, the distinction between FNH and other primary hepatic neoplasms is not possible. In these latter cases, close imaging follow-up, needle biopsy, or even surgical resection may be necessary.
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Contribution of CT to characterization of focal nodular hyperplasia of the liver.
Procacci C, Fugazzola C, Cinquino M, Mangiante G, Zonta L, Andreis IA, Nicoli N, Pistolesi GF.
Department of Radiology, University Hospital, Verona, Italy.
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Our personal series of 20 cases of focal nodular hyperplasia (FNH) of the liver is presented.
All lesions were studied with computed tomography (CT), 16 of which with surgical control. Retrospective evaluation of the CT features of the identified FNH, along with those of five hepatocellular adenomas (HCA) and 30 hepatocellular carcinomas (HCC), allowed the definition of specific patterns leading to a correct characterization of FNH in 78% of cases.
This greatly reduced the diagnostic errors, with the sole exception of patients with fatty liver in whom nuclear medicine may eventually provide a correct characterization. Fine-needle biopsy is thus only necessary in the dubious cases. A precise diagnostic workup of FNH is necessary, since it may avoid the surgical intervention.
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| GENERAL |
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Diagnosis of focal nodular hyperplasia of the liver by needle biopsy.
Makhlouf HR, Abdul-Al HM, Goodman ZD.
Division of Hepatic Pathology, Department of Hepatic and Gastrointestinal Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
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Focal nodular hyperplasia (FNH) of the liver can be a difficult diagnosis to establish in limited diagnostic samples such as a needle-core tissue biopsy, especially for pathologists with limited experience with the lesion.
To characterize the features that can be used to make the diagnosis, we reviewed and analyzed the clinicopathologic features of 100 consecutive cases submitted for consultation in which we were confident of the diagnosis of FNH in needle biopsy material. A diagnosis of FNH was correctly made by the contributing pathologist in 24 of the 100 referred cases. Most of the patients (81%) were women of childbearing age with a mean age of 36.75 +/- 9.82 years. Most of the patients (70%) were asymptomatic at diagnosis.
The most consistent diagnostic histological feature of FNH in needle biopsy was the presence of ductular reaction with varied intensity at the junction of the fibrous septa with the hepatocellular component, which was present in all 100 cases. Thick abnormal arteries were seen in all but 2 cases (n = 98). Features of chronic cholestasis with cholate stasis and accumulation of copper (demonstrable by the rhodanine stain) and copper-binding protein (demonstrable with the Victoria blue stain) were nearly as common (n = 94).
A confident diagnosis of FNH can be made with a needle biopsy, especially if the biopsy is known to come from a mass, and the lesion contains characteristic fibrosis with ductules at the interface between hepatocytes and the fibrous region, prominent arteries, and benign hepatocytes with features of chronic cholestasis.
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Focal nodular hyperplasia of the liver: pathological analysis of 11 cases.
Pan Y, Wang ZM, Mou LJ, Teng XD, Zheng ZJ, Ying LX.
Department of Pathology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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BACKGROUND: Focal nodular hyperplasia (FNH) is a benign tumor-like lesion of the liver, predominantly affecting women. Its etiology is obscure and its pathogenesis is poorly understood. FNH should be differentiated from other benign and malignant hepatic lesions. The aim of this study was to explore the pathological characteristics of FNH of the liver.
METHODS: Eleven patients with FNH were studied retrospectively by using hematoxylin and eosin, immunohistochemical and histochemical staining.
RESULTS: In 8 female and 3 male FNH patients aged 19 to 54 years (mean 32), most of lesions showed central scars macroscopically. Microscopically 8 patients were found of classical type, 2 were of telangiectic type, and 1 was of mixed type.
CONCLUSION: FNH is an uncommon benign hyperplastic lesion of the liver. It should be differentiated from hepatocellular adenoma, alpha-fetoprotein negative hepatocellular carcinoma, and fibrolamellar carcinoma.
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Histologic scoring of liver biopsy in focal nodular hyperplasia with atypical presentation.
Fabre A, Audet P, Vilgrain V, Nguyen BN, Valla D, Belghiti J, Degott C.
Service d'Anatomie Pathologique, Hopital Beaujon, Clichy, France.
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The contribution of radio-guided transcutaneous biopsy in the diagnosis of focal nodular hyperplasia (FNH) of the liver was compared with the findings on surgical specimens to assess its contribution in clinical and radiologic atypical cases.
This retrospective study involved 30 patients with atypical tumors on imaging who underwent liver biopsy and then surgery. All surgical specimens were diagnosed as FNH, either classical (n = 18) or nonclassical (n = 12). Imaging data were reviewed according to 4 radiologic criteria on magnetic resonance imaging (MRI) and/or computed tomography (CT) scan (hypervascularity, homogeneity, nonencapsulation, and presence of a central scar), and classified depending on the number of criteria found (group I, 4 of 4; group II, 3 of 4; group III, 2 or fewer).
Histologic assessment of ultrasound (US)-guided liver biopsy recorded major diagnostic features (fibrous bands, thick-walled vessels, reactive ductules, and nodularity) and minor features (sinusoidal dilatation and perisinusoidal fibrosis). "Definite FNH" (3 or 4 major features) was diagnosed in 14 biopsies, "possible FNH" (2 major and 1 or 2 minor features) in 7 cases, and "negative for FNH" (2 or fewer major features without minor features) in 9 cases. The diagnosis of FNH on biopsy was reached in 14 cases (58.3%) in patients with 2 or fewer imaging criteria (group III; n = 24). Biopsies with a diagnosis of "possible FNH" corresponded to a large proportion of telangiectatic-type FNH on the specimen.
In conclusion, liver biopsy does not appear to be necessary in cases in which imaging is typical. However, the absence of radiologic diagnostic criteria in FNH does not preclude a positive diagnosis on liver needle biopsy. Using the proposed histologic scoring system, surgical management may be avoided in these cases.
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FNH-like nodules: Possible precursor lesions in patients with focal nodular hyperplasia (FNH).
Lepreux S, Laurent C, Balabaud C, Bioulac-Sage P.
Service de Hepato-gastroenterologie, Hopital St Andre, CHU Bordeaux, France.
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BACKGROUND: The typical lesion of focal nodular hyperplasia (FNH) is a benign tumor-like mass characterized by hepatocytic nodules separated by fibrous bands. The solitary central artery with high flow and the absent portal vein give the lesions their characteristic radiological appearance. The great majority of cases seen in daily practice conform to the above description. Additional small nodules (from 1-2 up to 15-20 mm in diameter) detected by imaging techniques or on macroscopic examination may be difficult to identify as representing FNH if they lack the key features of FNH as defined in larger lesions. The aim of this study was to characterize these small nodules, and to compare their characteristics with those of typical lesions of FNH present in the same specimens.
RESULTS: Eight patients underwent hepatic resections for the removal of a mass lesion ("nodule") diagnosed as: FNH (1 patient); nodules of unknown nature (5 patients); or nodules thought to be adenoma or hepatocellular carcinoma (2 patients). Six nodules out of 9 discovered by imaging techniques met histopathological criteria for the diagnosis of typical FNH, at least in parts of the nodule; 2 nodules corresponded to a minor form of FNH ("subtle FNH") and one nodule to a steatotic area. Although FNH was thought to be found in a normal or nearly normal liver, this study revealed that, in addition, there were various types of small FNH-like nodules and vascular abnormalities in the liver with typical FNH nodule. The various types of small FNH-like nodules (n = 8, diameter 2 to 20 mm) consisted of the association to various degrees of numerous and/or enlarged arteries in portal tracts or in septa, with hyperplastic foci, slight ductular reaction, and regions of sinusoidal dilatation, accompanied by thin fibrous bands. Vascular abnormalities consisted of unpaired arteries, portal tracts with arteries larger than the associated bile duct, and regions of sinusoidal dilatation.
CONCLUSIONS: Although these small nodules can be considered as insufficient type or abortive forms of FNH, or adenoma, they can be precursors of the large mass lesions in which FNH was recognized and defined.
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| ATYPIA |
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Severe cytological atypia (large cell change) in focal nodular hyperplasia with numerous mallory bodies. A benign (adaptive) change?
Agaimy A, Kaiser A, Wuensch PH.
Institute of Pathology, Clinical Center of Nuremberg, Germany.
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Focal nodular hyperplasia (FNH) is a benign hepatocellular lesion composed of hyperplastic appearing hepatocytes arranged in nodules separated by fibrous septa that usually form a central stellate scar.
Rare lesions that show unusual cytological or architectural features were reported as variants of focal nodular hyperplasia.
We present the morphological features of a case of FNH with severe cytological atypia (so-called large cell change) in a 73-year-old man. In addition to diffuse cytological atypia, Mallory hyaline bodies were found in almost all lesional cells. This rare variant of FNH should be differentiated from other neoplastic lesions, in particular from the fibrolamellar variant of hepatocellular carcinoma.
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Cholestatic features in focal nodular hyperplasia of the liver.
Butron Vila MM, Haot J, Desmet VJ.
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| Liver. 1984 Dec;4(6):387-95. Abstract quote |
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Twenty specimens of focal nodular hyperplasia were studied with special attention to the histological features of chronic cholestasis (grouped under the headings of cholestasis, cholate-stasis and signs of ductular reabsorption).
In all specimens, evidence was found for one or more features of cholestasis and cholate-stasis. Signs of ductular reabsorption were less constant, and apparently varied according to the developmental stage of the lesion. The cholestatic features emphasize the bile secretory capacity of the lesional parenchyma, and are apparently due to the lack of real bile ducts in the portal tract equivalents of the lesional tissue. Evidence is presented that the "ductular component" in FNH is not due to proliferation of pre-existing ductules, but rather derives from ductular metaplasia of liver cell plates in zone 1 equivalents.
This metaplastic development of a ductular network may serve the function of reabsorbing the biliary constituents produced by the lesional parenchyma, leading to periductular inflammation and progressive fibrosis, thus producing an equivalent of biliary fibrosis and biliary cirrhosis.
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Spindle cell fragments in focal nodular hyperplasia of the liver. A case report.
Krishnamurthy S, Nerurkar AY.
Division of Cytopathology, Department of Pathology, 8th Floor, Annexe Building, Tata Memorial Hospital, Dr. E. Borges Road, Mumbai 400 012, India.
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BACKGROUND: There are only few reports on the fine needle aspiration cytology (FNAC) findings of focal nodular hyperplasia (FNH) of the liver.
CASE: A 30-year-old woman who had undergone surgery for a leiomyosarcoma of the calf, was found to have a hepatic mass five years later on imaging during routine follow-up. Fine needle aspiration was performed to rule out metastasis. Cytology revealed a few fragments of bland-looking spindle cells in a metachromatic stroma along with benign hepatocytes and bile duct cells. It was interpreted as "consistent with metastasis of leiomyosarcoma." The excised mass showed histologic features typical of FNH.
CONCLUSION: Spindle cell fragments have not been previously observed in the FNAC of FNH. These fragments probably represent the muscular wall of the abnormal blood vessels of FNH. If smooth muscle fragment is seen accompanying benign hepatocytes and bile duct cells, one should consider the diagnosis of FNH in the needle aspirate.
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| TELANGIECTATIC |
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Clinical, morphologic, and molecular features defining so-called telangiectatic focal nodular hyperplasias of the liver.
Bioulac-Sage P, Rebouissou S, Sa Cunha A, Jeannot E, Lepreux S, Blanc JF, Blanche H, Le Bail B, Saric J, Laurent-Puig P, Balabaud C, Zucman-Rossi J.
Department of Pathology, Centre Hospitalier Universitaire de Bordeaux, France.
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BACKGROUND & AIMS: Telangiectatic focal nodular hyperplasia (TFNH) of the liver is generally believed to belong to the focal nodular hyperplasia (FNH) family. The aim of this study was to use molecular markers, in addition to morphologic features, to better characterize TFNH.
METHODS: Thirteen patients with TFNH were compared with 28 patients with FNH and 17 patients with hepatocellular adenoma. Full clinical and morphologic data were analyzed. Molecular markers included determination of clonality by examining the active X chromosome, genome-wide allelotyping, a search for hepatocyte nuclear factor 1alpha (HNF1alpha) mutations, and determination of ANGPT1/ANGPT2 transcript levels.
RESULTS: No clinical differences were evident between patients with TFNH and adenoma; in particular, bleeding was observed in 77% and 53% of the cases, respectively. Patients with TFNH were more likely to experience nodule recurrence and the presence of multiple nodules than those with either FNH or adenoma. All TFNH and adenoma samples that were available for analysis were monoclonal, in contrast to 40% of the FNH samples. Chromosome losses confirmed monoclonality and were significantly less frequent in TFNH and FNH (22% and 26%) than in adenoma (53%). HNF1alpha mutations were found exclusively in half of the adenomas. ANGPT2 was overexpressed in TFNH and down-regulated in adenoma (P < .01) and FNH (P < .0005).
CONCLUSIONS: TFNHs are monoclonal lesions frequently subject to bleeding that are similar to adenomas not carrying HNF1alpha mutations and require a similar type of treatment. However, morphologic and molecular data support the hypothesis that TFNH is a separate entity.
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Telangiectatic focal nodular hyperplasia of the liver: a case detected at birth.
Kim HS, Kim YA, Kim CJ, Suh YL, Jang JJ, Chi JG.
Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
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A case of telangiectatic focal nodular hyperplasia (FNH) was detected at birth and was surgically removed. Grossly, the lesion was a solitary nodule and showed vague nodularity, appearing as an adenoma-like mass with fine fibrous septa, but having no macroscopic scar.
On microscopic scale, the mass typically had neither fibrous central scar nor hyperplastic nodules different from the usual FNHs. The hepatic plates were separated by sinusoidal dilatation, sometimes alternating with areas of marked ectasia. Instead of large fibrous scar, thin fibrous septa were often found, and contained abnormal tortuous large arteries. These high-pressure vessels were connected directly into the adjacent sinusoids and made marked dilation of sinusoids. Bile ductular proliferation was also noted in the thin fibrous septa.
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To our knowledge, this is considered to be the first reported case of telangiectatic FNH detected at birth.
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Laparoscopic resection of focal nodular hyperplasia.
Felsher J, Brody F.
Department of General Surgery, George Washington University, Washington, DC, USA.
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Focal nodular hyperplasia (FNH) is a benign liver lesion incidentally discovered with increasing frequency because of the proliferation of imaging studies.
Radiographic characterization can diagnose this pathologic lesion and nonoperative therapy is the standard of care. However, if radiographic studies and fine needle biopsy are inconclusive, operative intervention may be required.
Depending on the anatomic location of the lesion, biopsy and/or resection can be performed laparoscopically. A patient with biliary dyskinesia and focal nodular hyperplasia is presented.
She underwent laparoscopic cholecystectomy with excision of the FNH. This paper reviews the case as well as the diagnosis and treatment of FNH.
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Hepatic adenoma and focal nodular hyperplasia: diagnosis and criteria for treatment.
De Carlis L, Pirotta V, Rondinara GF, Sansalone CV, Colella G, Maione G, Slim AO, Rampoldi A, Cazzulani A, Belli L, Forti D.
Department of Surgery and Abdominal Transplantation, Niguarda Hospital, Milan, Italy.
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Focal nodular hyperplasia (FNH) and adenoma are rare benign hepatic tumors, and the standards for diagnosis and treatment still remain controversial. Usually adenoma is an indication for resection, due to its tendency to bleed and to degenerate; FNH, on the contrary, may be treated conservatively. Preoperation differential diagnosis is, however, difficult, often impossible.
MATERIALS AND METHODS: Thirty-eight patients with presumed hepatic adenoma and/or FNH were studied at our department from 1984 to 1996. Preoperative assessment included clinical evaluation and symptoms, laboratory tests, liver biopsy, ultrasound scan, computed tomography scan, magnetic resonance imaging, scintigraphy, and angiography. Thirteen patients had a presumed diagnosis of FNH, 16 of adenoma, and 9 of undetermined benign lesions; 27 had hepatic resections (3 with laparoscopic technique), and 11 were not operated on and are actually under a strict follow-up observation.
RESULTS: The final diagnosis was 19 FNH and 19 adenomas (2 of which contained areas of hepatocarcinoma). Presumed diagnosis was confirmed in 71% of cases. Use of oral contraceptives, abdominal symptoms, and pathologic liver test results were frequent in patients with adenomas. There were no deaths after surgery. All resected patients were tumor free during the follow-up, and in 10 of the 11 nonoperated cases, the size of the nodules remained unchanged. We conclude that precise diagnosis of these benign liver tumors remains difficult and sometimes impossible, despite new imaging techniques. Hepatic resections can be performed under very safe conditions; laparoscopic surgery may play a role in selected cases. Adenomas and uncertain cases are clear indications for surgery. Only when a diagnosis of FNH can be firmly confirmed in asymptomatic patients is strict observation without surgery recommended.
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