Focal Nodular Hyperplasia Nodules Research Articles

Focal nodular hyperplasia after systemic chemotherapy: Pathological features of a series of 15 cases

AbstractIntroductionChemotherapy, particularly oxaliplatin, has been associated with the development of focal nodular hyperplasia (FNH). Imaging diagnosis of FNH is well standardized, but it can be misdiagnosed as liver metastasis. The aim of this study was to describe the pathological features of FNH occurring after systemic chemotherapy.Materials and methodsFrom our pathological files for 1990‐2021, we retrieved 15 cases of resected newly developed FNH in adults with liver metastasis treated with systemic chemotherapy. Pathological features of FNH nodules and non‐tumoral liver samples were reviewed.ResultsIn 11/15 (73%) cases, FNH developed after an oxaliplatin‐based regimen. The median interval from the beginning of chemotherapy to the FNH diagnosis was 15 months. FNH was unique in 11 (73%) cases, and the median size of nodules was 1.1 cm [range 0.5‐2.5]. Histologically, 9 (60%), 11 (73%) and 11 (73%) cases exhibited fibrous central scar, dystrophic vessels and ductular proliferation, respectively, with all three criteria present in five (33%) cases. Eight (53%) cases showed intralesional steatosis and nine (60%) cases showed a glutamine synthetase immunostaining map‐like pattern. In non‐tumoral liver, eight (53%) cases exhibited sinusoidal obstruction syndrome and four (27%) nodular regenerative hyperplasia.ConclusionThe occurrence of FNH after systemic chemotherapy is an emerging condition challenging the imaging diagnosis because typical morphological features are frequently missing. The presence of sinusoidal changes, including regenerative hyperplasia, in non‐tumoral liver supports the potential role of chemotherapy in the pathogenesis of FNH.

Value of wash‐in and wash‐out time in the diagnosis between hepatocellular carcinoma and other hepatic nodules with similar vascular pattern on contrast‐enhanced ultrasound

The study aims to demonstrate whether the wash-in and wash-out time can be reliable as a criterion in the differential diagnosis between hepatocellular carcinoma (HCC) and other hepatic nodules with vascular pattern similar to HCC on contrast-enhanced ultrasound (CEUS). From February 2012 to February 2013, 214 patients with hepatic nodules displayed rapid hyperenhancement and quick wash-out on CEUS were included in this study. Before performing CEUS, all nodules were examined by grayscale ultrasonography and color Doppler techniques. CEUS was performed with SonoVue and low mechanical index technique. The initial time to enhancement, time to peak, time of the nodule being hypoenhanced were comparatively studied between HCCs and other hepatic nodules. Of all the 214 nodules, 209 were malignant (164 HCCs, 31 metastases, 10 intrahepatic cholangiocarcinomas (ICCs), 3 combined hepatocellular-cholangiocarcinomas, 1 epithelioid hemangioendothelioma), and five were benign (two inflammatory pseudotumors, one focal nodular hyperplasia nodule, one hemangioma, and one hyperplastic nodule). Metastases and ICCs showed more rapid wash-out than HCCs (P < 0.05): 16 of 31 metastases and 7 of all ICCs showed wash-out by 40 s after injection. Some focal liver lesions can show enhancement pattern similar to HCCs on CEUS. The wash-out time may be useful in the differential diagnosis.

Adenoma or Atypical Hepatic Focal Nodular Hyperplasia: Role of Preoperative Imaging and Laparoscopic Treatment

Differentiation of focal nodular hyperplasia (FNH) and other hypervascular liver lesions, such as hepatocellular adenoma (HCA), is important because of the drastically different therapeutic approach. However, FNH can be well distinguished only if it shows a typical aspect; alternatively, in the case of atypical FNH, imaging findings are not specific enough to provide a secure diagnosis and histologic verification of the lesion is required. In addition, HCA cannot be identified conclusively by any current available imaging technique and it can be at best suspected strongly, and this suspicion may lead to liver resection. Herein we report a case of a patient with an unusual FNH nodule presenting at ultrasonographic scanning as an isoechoic mass arising from hepatic segment 4b; the diagnostic indecision between FNH and HCA was not definitively solved even after computed tomography scan and magnetic resonance imaging and the patient was scheduled for a laparoscopic resection. The pathologic examination diagnosed an atypical FNH nodule. The clinical doubt between FNH and HCA remains a problem affecting the clinicians, and more effort should be made in the direction of a better preoperative differentiation of such different conditions. Surgical resection should not be considered as the failure of the preoperative diagnostic attempt, but as the mainstay for a definitive and sure diagnosis.

Diagnostic Features of Real-Time Contrast-Enhanced Ultrasound in Focal Nodular Hyperplasia of the Liver

The typical appearance of focal nodular hyperplasia (FNH) in radiological contrast techniques (helical CT or MRI) includes homogeneous enhancement in the arterial phase, but the exact timing for the best visualization of this pattern is unknown. The aim of the present study was to assess the ultrasound pattern of FNH with special attention to real-time contrast-enhanced ultrasonography (CEUS) appearance and specifically to the timing of perfusion patterns. 72 patients (60 females, 12 males) with a total of 90 FNH nodules with a diameter ranging from 8 to 100 mm (mean +/- SD, 40.6 +/- 21.5 mm) were examined continuously for at least 4 minutes using CnTI and CPS methods (ESAOTE, Genoa, Italy and Acuson-Siemens) after bolus injection of SonoVue (BRACCO, Milan, Italy). 87 of 90 nodules showed the typical coin-like hyperechogenicity in the arterial phase. The remaining three nodules were all in the same patient and were diagnosed as FNH after resection. Contrast started to appear within the lesions after a mean of 15.7 +/- 4.6 seconds (range 7 - 27 s) and reached peak signal intensity, with the greatest differentiation between the lesion and the surrounding parenchyma, at around 22.6 +/- 7.0 seconds (range 14 - 72 s). In the late phase, 65 lesions (72.2 %) became isoechoic (after a mean of 80.8 +/- 85.7 s, range 20 - 300 s), 22 (24.4 %) slightly hyperechoic and 3 (3.3 %) faintly hypoechoic. FNH shows a typical homogeneous hyperechoic pattern during the arterial phase in real-time CEUS which disappears slowly on average but occasionally even as soon as 20 seconds after contrast injection. If the first scans are taken later than 20 seconds after injection (which is still considered to be a full arterial phase), the ultrasound hyperechogenicity may be missed in some cases. Real-time study of these lesions is therefore strongly recommended to avoid possible false-negative results.

FNH-like nodules: Possible precursor lesions in patients with focal nodular hyperplasia (FNH)

BackgroundThe 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.ResultsEight 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.ConclusionsAlthough 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.

Hemodynamics of small hepatic focal nodular hyperplasia: evaluation with single-level dynamic CT during hepatic arteriography.

We examined the usefulness of single-level dynamic CT during hepatic arteriography to observe the hemodynamics of small hepatic focal nodular hyperplasia. Single-level dynamic CT during hepatic arteriography revealed not only centrifugal blood supply through the fibrous stellate scar, but also the drainage to dilated veins in or near the focal nodular hyperplasia nodule and directly to the hepatic sinusoid in the surrounding liver.

Etiological analysis of focal nodular hyperplasia of the liver, with emphasis on similar abnormal vasculatures to nodular regenerative hyperplasia and idiopathic portal hypertension

Pathological studies were performed on 23 cases of focal nodular hyperplasia (FNH) under the hypothesis that FNH is a hyperplastic lesion caused by abnormal vasculatures of portal tracts within the nodule. For a comparison of the histological features of portal tracts, nodular regenerative hyperplasia (NRH), idiopathic portal hypertension (IPH), chronic hepatitis and so-called normal liver were used as control tissues. Extranodular areas of FNH nodules were also examined. Clinical data were briefly summarized. Most of the portal tracts within FNH nodules showed various abnormal findings, such as dilatation and/or stenosis of portal vein, muscular thickening of arterial wall with dilated or stenotic lumina, lymphocyte infiltration, and bile ductule proliferation. However, portal vein thrombi were not found. These findings were not thought to represent compensatory reaction to portal vein thrombosis. Similar abnormal features were also observed in extranodular areas of FNH although to a milder degree. These abnormal features resembled those of NRH and IPH. Moreover, the characteristic scar-like tissues within FNH nodules were proved to be abnormally large portal tracts including large feeding arteries, portal veins and bile ducts. It has been believed that septa and scar-like tissue within FNH nodules are not portal tracts and that arterial malformation independent of portal tracts are related to the development of FNH. In addition, venous structures within FNH modules have until now not been considered to be portal veins. However, this study revealed that severe anomaly of portal tracts including portal veins and hepatic arterial branches existed in FNH nodules. Moreover, portal tracts in extranodular areas were also abnormal. Clinically, only one patient had a history of oral contraceptives. Based on these findings, congenital anomaly of the portal tracts histologically resembling the abnormal portal tracts of NRH and IPH may be related to the pathogenesis of FNH.

Hepatic focal nodular hyperplasia: specific findings at dynamic contrast-enhanced US with carbon dioxide microbubbles.

Dynamic contrast material-enhanced ultrasonography (US) with intraarterial infusion of carbon dioxide microbubbles was performed for four cases of histologically proved focal nodular hyperplasia (FNH) in four patients and for 167 cases of various hepatic nodules in 144 patients. No complications due to dynamic US were observed in any of the 148 patients. All FNH nodules were less than 3 cm in diameter. Consistent specific findings of FNH were not obtained with US, computed tomography, magnetic resonance imaging, radiocolloid scanning, or angiography in the four cases of FNH. In contrast, the characteristic vascular pattern (ie, early central hypervascular supply with centrifugal filling to the periphery at the arterial phase and a uniform or lobulated dense stain at the capillary phase) was observed in all four cases of FNH with dynamic US. This vascular pattern demonstrated in FNH with dynamic US was not seen in any of the 167 hepatic nodules, including 44 small hepatocellular carcinomas less than 3 cm in diameter. Therefore, the newly developed, dynamic contrast-enhanced US technique seems to be extremely sensitive and specific for diagnosing FNH and is useful in the differentiation of FNH from other hepatic tumors, especially hepatocellular carcinoma.