Fine needle aspiration biopsy for improving the diagnostic accuracy of cut needle biopsy of focal liver lesions

A clinically motivated self-supervised approach for content-based image retrieval of CT liver images

Deep learning-based approaches for content-based image retrieval (CBIR) of computed tomography (CT) liver images is an active field of research, but suffer from some critical limitations. First, they are heavily reliant on labeled data, which can be challenging and costly to acquire. Second, they lack transparency and explainability, which limits the trustworthiness of deep CBIR systems. We address these limitations by: (1) Proposing a self-supervised learning framework that incorporates domain-knowledge into the training procedure, and, (2) by providing the first representation learning explainability analysis in the context of CBIR of CT liver images. Results demonstrate improved performance compared to the standard self-supervised approach across several metrics, as well as improved generalization across datasets. Further, we conduct the first representation learning explainability analysis in the context of CBIR, which reveals new insights into the feature extraction process. Lastly, we perform a case study with cross-examination CBIR that demonstrates the usability of our proposed framework. We believe that our proposed framework could play a vital role in creating trustworthy deep CBIR systems that can successfully take advantage of unlabeled data.

Optimizing small liver biopsy specimens: a combined cytopathology and surgical pathology perspective

Both fine-needle aspiration (FNA) and core needle biopsy (CNB) are widely used to obtain liver biopsy specimens, particularly from mass lesions. However, the advantages and disadvantages of FNA versus CNB in terms of appropriate use, diagnostic yield, complications, and whether or not specimens should be handled by cytopathologists, surgical pathologists, or both remain subjects of controversy. This review addresses the issues of sample adequacy, appropriate use of each technique and complications, and challenges regarding the diagnosis of both hepatic tumors and non-neoplastic liver disease.

Approach to the Solitary Liver Lesion: Imaging and When to Biopsy

The characterization and management of focal liver lesions is a commonly encountered problem in radiology. While the imaging findings will often be diagnostic, in equivocal cases the decision of how to proceed may be challenging. The primary modalities for liver lesion characterization are multiphase contrast-enhanced computed tomography and magnetic resonance imaging. Most lesions have typical imaging features, and when taken in conjunction with patient demographics and biochemistry the diagnosis can usually be made. Ancillary imaging modalities such as contrast-enhanced ultrasound and hepatobiliary specific contrast agents are also useful. Cirrhotic livers present a challenge due to the spectrum of benign, dysplastic, and malignant nodules that can occur. The report should include information necessary for accurate staging, and published standardized reporting guidelines should be taken into consideration. A decision to proceed to biopsy should be made only after multidisciplinary review of the case. If biopsy is required, fine needle aspiration is usually sufficient, though core needle biopsy may be required in certain circumstances.

The role of interventional radiology in the management of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (hcc) is one of the most common causes of cancer-related death worldwide. Overall, liver transplantation and resection are the only available treatments with potential for cure. Various locoregional therapies are widely used to manage patients with advanced hcc or as a bridging therapy for patients with early and intermediate disease. This article reviews and evaluates the role of interventional radiology in the management of such cases by assessing various aspects of each method, such as effect on rates of survival, recurrence, tumour response, and complications.

METHODS

A systemic search of PubMed, medline, Ovid Medline In-Process, and the Cochrane Database of Systematic Reviews retrieved all related scientific papers for review.

RESULTS

Needle core biopsy is a highly sensitive, specific, and accurate method for hcc grading. Portal-vein embolization provides adequate expansion of the future liver remnant, making more patients eligible for resection. In focal or multifocal unresectable early-stage disease, radiofrequency ablation tops all other thermoablative methods. However, microwave ablation is preferred in large tumours and in patients with Child-Pugh B disease. Cryoablation is preferred in recurrent disease and in patients who are poor candidates for anesthesia. Of the various transarterial modalities-transarterial chemoembolization (tace), drug-eluting beads, and transarterial radio-embolization (tare)-tace is the method of choice in Child-Pugh A disease, and tare is the method of choice in hcc cases with portal vein thrombosis.

CONCLUSIONS

The existing data support the importance of a multidisciplinary approach in hcc management. Large randomized controlled studies are needed to provide clear indication guidelines for each method.

HCC-ART score, a simple, highly sensitive and specific test for early diagnosis of hepatocellular carcinoma: a large-scale, multicentre study

Background:

A simple scoring system is needed to discriminate HCC from patients with chronic liver diseases (CLD). The simplest score would be one that requires only variables that can be documented simply from routine laboratory tests without the need for sophisticated tests.

Methods:

Data from the estimation group (1351 patients) and the validation group (2208 patients) were retrospectively analysed. Liver fibrosis-negative control and liver cirrhosis were compared with HCC. Area under ROC curve (AUC) were used to develop HCC-α-fetoprotein-routine test (HCC-ART).

Results:

Hepatocellular carcinoma-AFP-routine test showed diagnostic accuracy for liver cirrhosis vs HCC with ROC curves of 0.99%, sensitivity of 97%, and specificity of 96% in the estimation, and 0.95%, 90%, and 83%, respectively, in the validation. Sensitivity (97%) and specificity (100%) were obtained to discriminate HCC from liver fibrosis. Area under curve for AFP at 400 U l⁻¹ was 0.70, sensitivity was 41%, and specificity was 99% in the estimation, and 0.77%, 54%, and 99%, respectively, in the validation. The AUC for HCC-ART in HCC with single tumour, absent vascular invasion, size <2 cm and CLIP score (0–1) were 0.95, 0.93, 0.86, 0.87, respectively, compared with 0.72, 0.71, 0.71, 0.50, respectively, for AFP.

Conclusion:

Hepatocellular carcinoma-AFP-routine test could increase the accuracy of HCC screening and surveillances and could be used worldwide without extra efforts.

Fine needle aspiration cytopathology of liver masses: 101 cases with cyto-/histopathological analysis

OBJECTIVE

Appropriate clinical management of a hepatic mass depends on its accurate diagnosis. We aimed to evaluate sensitivity, specificity and accuracy of percutaneous fine needle aspiration cytopathology (FNAC) in the diagnosis of suspicious liver masses in our center.

STUDY DESIGN

Cytopathology and histopathology databases were searched for patients undergoing combined, image-guided percutaneous FNAC and biopsy sampling of liver mass lesions in 2006-2011. All patients had one or more radiologically detected lesion and clinical suspicion of neoplastic disease. Sensitivity, specificity and accuracy of FNAC in the diagnosis of liver lesions were determined using histopathological diagnoses on liver biopsy as a gold standard.

RESULTS

Of 101 patients, cytopathological diagnoses were nonneoplastic in 10 cases while 10 cases were suspicious for neoplasms and 71 were malignant. In 10 patients (9.9%), FNA samples were inadequate for assessment. Final histopathological diagnoses were nonneoplastic in 7 cases, benign tumoral in 5 and malignant in 89 cases (88.1%). Of the malignancies, 22 (24.7%) were hepatocellular carcinomas (HCC) and 60 (67.4%) were metastatic tumors on final clinicohistopathological analysis. The remaining 7 (7.8%) patients had other primary hepatic malignancies. Fifteen of the 22 (68.2%) HCC cases were specifically diagnosed by FNAC. In 28 of the metastatic tumors, the primary organ site was unknown, followed by gastrointestinal malignancies in 17 cases. Overall, sensitivity, specificity, accuracy, and positive and negative predictive values of FNAC in the diagnosis of neoplastic lesions were 96.3, 90.0, 95.6, 98.7 and 75.0%, respectively. Discrepancy in cyto-/histopathological data was mainly seen in nonrepresentative FNAC cases.

CONCLUSION

FNAC of liver masses is a highly accurate technique that can be used to identify the majority of primary/metastatic hepatic neoplasias with high specificity. A combined cyto-/histopathological approach provides higher accuracy in the diagnosis and typing of hepatic tumors, which may affect therapeutic decisions. Correlation of cytopathology with clinicoradiological findings is helpful to increase overall accuracy of the procedure.

Value of ultrasonography-guided fine needle aspiration cytology in the investigative sequence of hepatic lesions with an emphasis on hepatocellular carcinoma

Background:

The evaluation and management of various hepatic lesions is a common clinical problem and their appropriate clinical management depends on accurate diagnoses.

Aims:

To study the cytomorphological features of distinctive non-neoplastic and neoplastic lesions of the liver and to evaluate the sensitivity, specificity and diagnostic accuracy of ultrasonography (USG)-guided fine needle aspiration cytology (FNAC) in the diagnosis of liver diseases.

Materials and Methods:

Seventy-two patients with evidence of liver diseases underwent USG-guided, percutaneous FNAC. Cytomorphological diagnoses were correlated with clinical, biochemical and radiological findings, histopathological diagnoses and follow-up information.

Results:

The age of the patients ranged from eight months to 90 years with 48 males (66.67%) and 24 females (33.33%). Of the 72 cases, the cytological diagnosis was rendered in 71 patients and smears were inadequate for interpretation in one case. Neoplastic lesions (68.06%) were more common than non-neoplastic lesions (30.56%). The majority of the neoplastic lesions were hepatocellular carcinomas (36.12%) followed by metastatic adenocarcinomas (19.45%). Among non-neoplastic lesions, cirrhosis was the commonest lesion (8.34%). The overall diagnostic accuracy of FNAC was 97.82% with a sensitivity and specificity of 96.87 and 100% respectively.

Conclusion:

USG-guided FNAC of the liver is a safe, simple, cost-effective and accurate method for cytological diagnosis of hepatic diffuse, focal/nodular and cystic lesions with good sensitivity and specificity.

Approach to Solid Liver Masses in the Cirrhotic Patient

Liver masses in cirrhosis are increasingly being recognized with the use of new imaging modalities. The majority of these lesions are detected by ultrasound, enhanced CT and MRI. The most likely diagnosis of a solid liver lesion in a cirrhotic liver is hepatocellular carcinoma, followed by high grade or low grade dysplastic nodule, and cholangiocarcinoma. Lymphoma and liver metastasis are extremely rare. Diagnosis is made by contrast enhanced ultrasound, multi detector (MDCT) and MRI. Fine needle core biopsy (FNCB) or aspiration (FNAB) or both may be required in doubtful cases. If uncertainty persists on the nature of the lesion, surgical liver resection is recommended. This review discusses the main characteristics of the most common solid liver masses in cirrhotic patient.

Characteristics of common solid liver lesions and recommendations for diagnostic workup

Due to the widespread clinical use of imaging modalities such as ultrasonography, computed tomography and magnetic resonance imaging (MRI), previously unsuspected liver masses are increasingly being found in asymptomatic patients. This review discusses the various characteristics of the most common solid liver lesions and recommends a practical approach for diagnostic workup. Likely diagnoses include hepatocellular carcinoma (the most likely; a solid liver lesion in a cirrhotic liver) and hemangioma (generally presenting as a mass in a non-cirrhotic liver). Focal nodular hyperplasia and hepatic adenoma should be ruled out in young women. In 70% of cases, MRI with gadolinium differentiates between these lesions. Fine needle core biopsy or aspiration, or both, might be required in doubtful cases. If uncertainty persists as to the nature of the lesion, surgical resection is recommended. If the patient is known to have a primary malignancy and the lesion was found at tumor staging or follow up, histology is required only when the nature of the liver lesion is doubtful.

Diagnosis and treatment of benign focal liver lesions

BACKGROUND

With the routine use of improved imaging modalities, more benign liver lesions are detected nowadays. An accurate characterization of these incidental lesions may be a challenge, and frequently a biopsy or even unnecessary surgery is being performed. However, these interventions are not always to the benefit of the patient.

METHODS

A Medline search of studies relevant to imaging diagnosis and management of the most common, benign, solid and non-solid liver lesions was undertaken. References from identified articles were handsearched for further relevant articles. The authors' own experiences with benign liver lesions were also taken into account.

RESULTS

Although atypical imaging features are the exception rather than the rule, it is sometimes difficult to differentiate between benign and malignant lesions, and knowledge of their imaging features is essential if unnecessary work-up is to be avoided. The use of tissue-specific contrast media, which has clearly improved the accuracy of highly advanced radiological techniques, may be helpful during differential diagnosis. Once having established an accurate diagnosis, surgery is rarely indicated for a benign liver lesion because of its asymptomatic nature.

CONCLUSION

Knowledge of imaging features and a clear management strategy during diagnostic work-up, emphasizing the indications for surgery, will minimize the number of patients who have to undergo biopsy or unnecessary surgery.

Diagnosis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the commonest cancers worldwide, particularly in parts of the developing world, and is increasing in incidence. This article reviews the current modalities employed for the diagnosis of HCC, including serum markers, radiological techniques and histological evaluation, and summarises international guidelines for the diagnostic approach to HCC.

Algorithm for immediate cytologic diagnosis of hepatic tumors

OBJECTIVE

Immediate cytologic assessment of hepatic lesions can help determine the adequacy of specimens and may yield a preliminary diagnosis. The purpose of this study was to analyze the diagnostic accuracy of on-site cytologic assessment compared with definitive cytologic examination in the detection and correct subtyping of malignant hepatic lesions.

SUBJECTS AND METHODS

The study population included 472 consecutively registered patients with hepatic nodules who underwent sonographically guided fine-needle aspiration and core biopsies. During on-site cytologic analysis, the pathologist made a preliminary diagnosis of malignancy or negative for malignancy for each nodule. When a malignant lesion was diagnosed, immediate subtyping was attempted.

RESULTS

With immediate cytologic analysis, 280 (80.9%) of 346 malignant nodules were correctly identified without false-positive cases. With immediate subtyping, 113 (68.1%) of 166 cases of hepatocellular carcinoma, 28 (77.8%) of 36 cases of cholangiocarcinoma, and 113 (85.0%) of 133 cases of metastasis were detected.

CONCLUSION

High diagnostic accuracy for malignancy can be achieved with on-site cytologic evaluation of hepatic tumors. Specific diagnoses of hepatocellular carcinoma, cholangiocarcinoma, and metastasis also can be made on-site in most cases. The absence of false-positive diagnosis of malignancy at on-site cytologic examination may make additional biopsy unnecessary. We propose an algorithm for the cytohistopathologic management of hepatic tumors.

Immunocytochemical diagnosis of hepatocellular carcinoma and identification of carcinomas of unknown primary metastatic to the liver on fine-needle aspiration cytologies

BACKGROUND

Difficulties with cytologic diagnoses on fine-needle aspiration cytology (FNAC) of the liver can be overcome by the application of immunocytochemical panels applied on smears. The aim of the current study was to analyze the performance of a panel of monoclonal antibodies to differentiate hepatocellular carcinoma (HCC) from metastatic carcinoma (MC) or regenerative nodules, and to identify the to date unknown primary sites of carcinomas that had metastasized to the liver.

METHODS

In a validating cohort study, 108 FNACs coin lesions in the liver were routinely evaluated applying immunocytochemistry as an ancillary method. All patients had confirmatory histologic and/or clinical follow-up. A total of 23 HCCs were analyzed for the distinction from MC or regenerative nodules applying a panel of HepPar1, alpha-fetoprotein, BerEP4, CD31, CD68, and Ki-67. A total of 85 cases of unknown primary tumor metastatic to the liver were used to identify the tumor sites applying a panel of CK5/6, CK7, CK20, CA 125, thyroid transcription factor-1 (TTF-1), and Cdx2.

RESULTS

Typing accuracy to differentiate HCC from MC or regenerative nodules was 100% and 90.3%, respectively, to identify the primary tumor site of MC. In 23 cases, the site of the primary tumor remained clinically unknown.

CONCLUSIONS

The application of immunocytochemical panels on the same slide used for microscopic diagnosis is a useful tool in the routine assessment of FNACs of the liver to discriminate HCCs from MC or regenerative nodules and for the identification of primary sites of MC. Their performance should be confirmed in a larger series of cases.

Flowcytometric quantitation of hepatitis B viral antigens in hepatocytes from regular and fine-needle biopsies

The aim of the study was to investigate the use of flow cytometry, as an alternative for immunohistochemistry, for the detection of viral antigens in the liver of patients with chronic hepatitis B virus (HBV) infection. Hepatocytes were obtained from regular- and fine-needle biopsy from HBV positive (n=17) and negative (n=7) patients and quantified by flow cytometry for intracellular hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg). Number of HBsAg positive hepatocytes ranged from 0 to 83%. A significant correlation was found between the percentage of infected hepatocytes and the intracellular expression level of HBsAg (R=0.841, p<0.001). The specificity and sensitivity of flow cytometry was similar to immunohistochemistry. Of the patients on anti-viral treatment with undetectable serum HBV DNA (<400 copies/ml), two had high HBsAg expression in the liver. HBcAg staining was found in 3 out of 15 patients, with 2-3% positive hepatocytes. The results obtained with fine-needle aspiration biopsy (n=12) were comparable to regular biopsy. In conclusion, flowcytometric quantitation of HBV antigens is sensitive and provides relevant information on the course of infection. The minimally invasive fine-needle biopsy provides a useful alternative for regular-needle biopsy for monitoring intrahepatic antiviral responses during therapy.

The diagnostic value of on-site cytopathological evaluation and cell block preparation in fine-needle aspiration cytology of liver masses

OBJECTIVE

The aims of this study were to evaluate the typing accuracy of conventional smear (CS), cell block (CB) preparations and combined use of both procedures (CS + CB) for the diagnosis of hepatic malignancies and to determine whether immediate on-site cytopathological evaluation improves the diagnostic yield of liver fine-needle aspiration cytology (FNAC).

METHODS

Ultrasound-guided FNABs were performed on 323 consecutive cases with liver masses between December 2002 and December 2004. Histologically and/or clinically correlated 167 cases were included in the study. Preliminary FNAB results, results of CS, CB, and combined use of CS and CB were compared regarding diagnostic sensitivity, specificity, and accuracy for the diagnosis of malignancy. Subtyping accuracies of different methods were also compared.

RESULTS

The sensitivity of on-site cytopathological examination and CS were both 92.8%. The sensitivity of CS + CB was slightly better than that of CB (93.5% versus 84.8%). Specificity of all procedures was achieved 100%. Diagnostic accuracy of on-site cytopathological evaluation, CS, CB, and CS + CB were 93.9%, 93.9%, 87.2%, and 94.5%, respectively. A specific subtype diagnosis of malignant tumours could be rendered accurately on the basis of preliminary diagnosis in 71%, CS in 75.4%, CB in 78.3% and combined approach in 92% of cases. In terms of typing accuracy, 87.5% of HCCs, 93.2% of adenocarcinomas, 92.3% of neuroendocrine carcinomas, 100% of lymphomas and 100% of other malignant tumours were correctly subclassified in the final cytopathological diagnosis. The agreement between preliminary diagnosis and final cytopathological diagnosis was 77.2%.

CONCLUSION

With use of on-site cytopathological evaluation and combined use of CS and CB, the diagnostic accuracy of liver tumours approaches 100% and also significantly improve diagnostic and subtyping accuracy of liver malignancies.

Flow cytometry of fine-needle-aspiration biopsies: a new method to monitor the intrahepatic immunological environment in chronic viral hepatitis

Information about the character and grade of the intrahepatic immune response in viral hepatitis is important for the evaluation of disease stage and effect of therapy. Complications like haemorrhage limit the frequent performance of tissue-needle biopsies (TB), and the cells of peripheral blood have to be used as surrogate markers instead. Fine-needle-aspiration biopsy (FNAB) of the liver represents a safe and atraumatic method that allows frequent cytological sampling. Our aim was to investigate whether flow cytometry of FNAB specimens allows co-analysis of phenotype, function and specificity of key populations of liver-infiltrating lymphocytes (LIL). In 20 consecutive patients with chronic viral hepatitis [10 hepatitis B virus (HBV), 10 hepatitis C virus (HCV)], flow cytometry was performed on FNAB cytology, and simultaneously on lymphocytes isolated from a TB and peripheral blood mononuclear cells (PBMC). The ratio of CD8+/CD4+ lymphocytes in FNAB correlated well with LIL from TB (r =0.78, P < 0.05) but differed from PBMC (mean ratio: 2.6, 2.1 and 0.7, respectively). Similarly, a correlation was observed for percentage CD56+ natural killer (NK) cells (mean %: 29.9, 32.3 and 14.5, respectively; r = 0.69, P < 0.05). The percentage of interferon (IFN)-gamma-producing CD3+ lymphocytes in both FNAB and TB was higher than in PBMC (mean %: 41, 44 and 22, respectively; P < 0.05). Furthermore, tetrameric complexes allowed analysis of HBV-specific T cells in FNAB specimens. In conclusion, flow cytometry of FNAB allows easy, atraumatic and reliable analysis of lymphocytes obtained from the intrahepatic compartment. Therefore, the FNAB is a valuable tool in the study of the immunopathology of viral hepatitis, and it may contribute to the improved clinical evaluation of chronic viral liver disease.

Fine needle aspiration biopsy of the liver: Algorithmic approach and current issues in the diagnosis of hepatocellular carcinoma

The role of fine needle aspiration biopsy (FNAB) in the evaluation of focal liver lesions has evolved. Guided FNAB is still useful to procure a tissue diagnosis if clinical, biochemical and radiologic findings are inconclusive. Major diagnostic issues include: (i) Distinction of benign hepatocellular nodular lesions from reactive hepatocytes, (ii) Distinction of well-differentiated hepatocellular carcinoma (WD-HCC) from benign hepatocellular nodular lesions, (iii) Distinction of poorly differentiated HCC from cholangiocarcinoma and metastatic carcinomas, (iv) Determination of histogenesis of malignant tumor, and (v) Determination of primary site of origin of malignant tumor. This review gives a general overview of hepatic FNAB; outlines an algorithmic approach to cytodiagnosis with emphasis on HCC, its variants and their mimics; and addresses current diagnostic issues. Close radiologic surveillance of high-risk cirrhotic patients has resulted in the increasing detection of smaller lesions with many subjected to biopsy for tissue characterization. The need for tissue confirmation in clinically obvious HCC is questioned due to risk of malignant seeding. When a biopsy is indicated, core needle biopsy is favored over FNAB. The inherent difficulty of distinguishing small/early HCC from benign hepatocellular nodular lesions has resulted in indeterminate reports. Changing concepts in the understanding of the biological behavior and morphologic evolution of HCC and its precursors; and the current lack of agreement on the morphologic criteria for distinguishing high-grade dysplastic lesions (with small cell change) from WD-HCC, have profound impact on nomenclature, cytohistologic interpretation and management. Optimization of hepatic FNAB to enhance the yield and accuracy of diagnoses requires close clinicopathologic correlation; combined cytohistologic approach; judicious use of ancillary tests; and skilled healthcare teams.

Diagnosis, staging and treatment of hepatocellular carcinoma

Hepatocellular carcinomas are aggressive tumors with a high dissemination power. An early diagnosis of these tumors is of great importance in order to offer the possibility of curative treatment. For an early diagnosis, abdominal ultrasound and serum alpha-fetoprotein determinations at 6-month intervals are suggested for all patients with cirrhosis of the liver, since this disease is considered to be the main risk factor for the development of the neoplasia. Helicoidal computed tomography, magnetic resonance and/or hepatic arteriography are suggested for diagnostic confirmation and tumor staging. The need to obtain a fragment of the focal lesion for cytology and/or histology for a diagnosis of hepatocellular carcinoma depends on the inability of imaging methods to diagnose the lesion. Several classifications are currently available for tumor staging in order to determine patient prognosis. All take into consideration not only the stage of the tumor but also the degree of hepatocellular dysfunction, which is known to be the main factor related to patient survival. Classifications, however, fail to correlate treatment with prognosis and cannot suggest the ideal treatment for each tumor stage. The Barcelona Classification (BCLC) attempts to correlate tumor stage with treatment but requires prospective studies for validation. For single tumors smaller than 5 cm or up to three nodules smaller than 3 cm, surgical resection, liver transplantation and percutaneous treatment may offer good anti-tumoral results, as well as improved patient survival. Embolization or chemoembolization are therapeutic alternatives for patients who do not benefit from curative therapies.

Fine needle biopsy of focal liver lesions: the hepatologist's point of view

Guided biopsy of hepatocellular carcinoma has been recently discussed again due to the progress of imaging techniques and the risk of malignant seeding after the procedure. Ultrasound is probably still the most accurate imaging modality for early detection of nodules arising on cirrhosis, even when compared with more advanced imaging techniques. It can be easily employed in the surveillance of high-risk cirrhotic patients. Ultrasound-guided biopsy has very high sensitivity and almost absolute specificity, which allows the appropriate treatment to start after a positive diagnosis. It also allows correct diagnosis of lymphomatous nodules, the incidence of which is increased in hepatitis C virus-related cirrhosis. The risk of seeding appears limited according to the currently available epidemiological data; this should be considered against the risk of false-positive diagnosis of malignancy based on imaging studies alone. Ultrasound-guided biopsy is a valuable tool also for the diagnosis of small nodules (less than 10 mm in diameter). The best accuracy in the sampling of hepatocellular carcinoma nodules is obtained by combining smear cytology and microhistology. This can be achieved by a single biopsy with a fine cutting needle that furnishes pathologic material suitable for both examinations, reducing risks and costs.

Cytologic features and histologic correlations of microacinar and microtrabecular types of well-differentiated hepatocellular carcinoma in fine-needle aspiration biopsy

BACKGROUND

Well-differentiated hepatocellular carcinoma (HCC) in fine-needle aspiration (FNA) biopsy is characterized by trabeculae three or more cells thick wrapped by peripheral endothelium. The authors encountered another pattern that did not fulfill these classic criteria for malignancy yet was proven to be HCC in clinical follow-up. The objective of this study was to characterize the cytologic features of this pattern with histologic correlations.

METHODS

Over a period of 6.5 years, 14 of 123 cases (11.4%) of HCC from 428 liver aspirates showed the unusual pattern. Their cytologic features were compared with 14 cases of nonneoplastic liver on FNA smears that were processed with Ultrafast Papanicolaou stain, and their histologic features were compared on cell blocks with hematoxylin and eosin stain and reticulin stain.

RESULTS

The unusual type of well differentiated HCC in FNA smears was characterized by numerous, small hepatocytes with minimal nuclear atypia but reduced cytoplasm, grouped together in microacini of five or more cells and microtrabeculae one or more cells thick of irregular thickness with no apparent peripheral endothelium. Transgressing capillaries were found when the smears were inspected carefully. In histology nine cases that were the compact type of HCC, two cases that were the microacinar type of HCC, and three cases that were the microtrabecular type of HCC. All FNAs showed deficient reticulin framework. All 14 cases of nonneoplastic liver aspirate were characterized by the presence of large tissue fragments that were resistant to smearing.

CONCLUSIONS

Well differentiated HCC may present as microtrabeculae of irregular thickness one or more cells thick with inapparent peripheral endothelium or as microacini mimicking neuroendocrine carcinoma.