Stereotaxic fine needle aspiration cytology of clinically occult malignant and premalignant breast lesions

Stereotaxic fine needle aspiration (FNA) cytology was used to study clinically occult (nonpalpable) breast lesions in 114 consecutive patients with mammographically suspicious findings prior to excisional biopsy. The aspirate contained insufficient material for cytologic evaluation in 15 cases (13.2%), which were histologically diagnosed as benign (7 cases), atypical hyperplasia (7 cases) or carcinoma in situ (1 case). The cytologic findings indicated a benign lesion in 77 cases (67.5%), which were histologically diagnosed as benign (71 cases) or atypical ductal hyperplasia (6 cases). The cytologic sample showed atypia in eight cases (7.0%), which were histologically diagnosed as severe atypical ductal hyperplasia (three cases), carcinoma in situ (one case) or proliferative fibrocystic disease (four cases). In the eight cases (7.0%) cytologically interpreted as probably malignant, histology confirmed six invasive carcinomas, one carcinoma in situ and one fibrocystic disease. Of six cases (4.4%) cytologically reported as malignant, five were histologically diagnosed as invasive carcinoma and one as carcinoma in situ. Overall, stereotaxic FNA cytology reported as malignant or probably malignant 14 of the 15 cases with a histologic confirmation of malignancy, for a sensitivity of 93.3%. Cytology correctly identified 78 of the 83 histologically negative cases, for a specificity of 94.0%. The 16 cases histologically diagnosed as ductal hyperplasia, which carries a high risk for subsequent malignancy, were studied in detail in an effort to define histologic and cytologic criteria for this entity. Using selected histologic criteria, 11 of these cases were graded as showing mild-to-moderate atypical hyperplasia and 5 as showing severe atypical hyperplasia. Three of the latter cases were similarly identified by an analogous cytologic grading; the other two cases had insufficient cytologic samples. The total results in this series of 114 cases support the use of stereotaxic FNA cytology in the diagnosis of these nonpalpable breast lesions, examples of which are illustrated. In particular, it may help to raise the low specificity yielded by mammography alone, which would represent a significant advance for the patient in terms of the accuracy, expediency and reduced cost of diagnosing these lesions.     

Fine needle aspiration cytology of focal liver lesions. Results obtained with examination of both cytologic and histologic preparations

The results of 197 consecutive fine needle aspirations (FNA) of focal liver lesions performed on 176 patients were reviewed, and the 176 single most diagnostic aspirates were analyzed in detail. The majority of specimens were obtained using a 20-gauge or 22-gauge needle with ultrasound guidance. An attempt was made to obtain both a cytologic and a tissue specimen from each aspirate. The overall accuracy of the procedure was 85%; the accuracies of the tissue and cytologic specimens were 67% and 73%, respectively. The combined procedure detected 81% of the documented malignant tumors; the tissue specimen detected 62%. Eleven tumors were identified only in the tissue specimen and 23 were identified only in the cytologic specimen. There were no false-positive diagnoses. Six of nine hepatocellular carcinomas were detected. These results show that FNA cytology is a safe, accurate, relatively noninvasive technique whose diagnostic yield may be improved by examination of both a histologic tissue and a cytologic preparation.     

Differential diagnosis of malignant intrahepatic tumors by ultrasonically guided fine needle aspiration biopsy and by laparoscopic/intraoperative biopsy. A comparative study

Thirty-six cases of ultrasonographically detected liver tumors (28 malignant and 8 benign lesions) were investigated by both fine needle aspiration (FNA) biopsy and laparoscopic or intraoperative tissue biopsy. The sensitivity of FNA biopsy in detecting a neoplasm was 85.7% while that of tissue biopsy was 82.1%. Specificity was 100% in both methods. A correct histologic diagnosis of the neoplasm could be made on the cytologic smear in only 14 cases (50.0%) due to technical and methodologic difficulties. Endoscopic and intraoperative tissue biopsy yielded sufficient material to make a definite histologic tumor diagnosis in 23 of 28 cases. Additional information on tumor spread and sequelae of liver infiltration was obtained by macroscopic tissue observations in nine cases. These results indicate that FNA biopsy is less sensitive in the classification of primary or secondary liver tumors and that tissue biopsies obtained during laparoscopy or laparotomy are required if a suspected hepatic neoplasm needs to be classified exactly to plan therapy and to establish a prognosis.     

Fine needle aspiration cytology of endocrine neoplasms of the pancreas. Morphologic and immunocytochemical findings in 20 cases

OBJECTIVE: To analyze the role of fine needle aspiration (FNA) cytology in the preoperative diagnosis of pancreatic endocrine neoplasms. METHODS: Cytologic and histologic diagnoses of pancreatic endocrine tumors were reviewed. A total of 20 FNA cytologic procedures from 20 patients were selected. A false positive case, a retroperitoneal paraganglioma, was also reviewed. Two groups of patients were established: (1) those in whom a surgical biopsy with an immunohistochemical study was available (n = 13), and (2) those with a pancreatic tumor in which the diagnosis was confirmed by immunocytochemical studies (n = 7). In 13 cases the pancreatic tumor was aspirated, while in 7, liver metastases were studied. The immunoexpression of chromogranin and synaptophysin was evaluated in alcohol-fixed smears from 12 and 11 cases, respectively. RESULTS: One false negative and 1 false positive diagnosis were present. In the remaining 19 cases a cytologic diagnosis of pancreatic endocrine tumor was given. Main cytologic features were: (1) a prominent cellular dissociation with many single cells and small, poorly cohesive groups; (2) intermediate to large size cells with ill-defined cytoplasm, naked or eccentric nuclei, and frequent binucleation; and (3) variable nuclear pleomorphism with the characteristic finely granular distribution of the chromatin. Immunocytochemical evidence of endocrine differentiation (chromogranin or synaptophysin) was present in the 12 cases analyzed. CONCLUSION: FNA cytology offers the possibility of a precise preoperative, noninvasive diagnosis of pancreatic endocrine tumors. Cytologic features differ considerably from those of pancreatic adenocarcinoma, allowing differentiation from nonfunctioning endocrine neoplasms. In difficult cases immunocytologic studies are very helpful.     

Solitary liver nodules.

There has been confusion in the literature over the nomenclature of solitary liver nodules. Several such lesions have recently been reported in patients taking oral contraceptives. Similarities exist between these cases that suggest they may be examples of focal nodular hyperplasia. Here three further cases are presented. The criteria for making the diagnosis and its importance are discussed.     

Fine needle aspiration cytodiagnosis of liver tumors

OBJECTIVE: To present our experience with liver fine needle aspiration (FNA) diagnosis and the adjunctive use of cell blocks with reticulin stain. STUDY DESIGN: The authors reviewed the results of cytopathologic diagnosis obtained by FNA biopsy over a 1-year period, from January 2000 to December 2000, in patients who presented primarily with ultrasonographically suspected liver nodules. FNA smears from 936 patients and cell blocks from 796 patients were reviewed. RESULTS: Among the 936 aspirates studied, the most common malignancy was hepatocellular carcinoma (HCC), which was diagnosed in 427 cases (45.6%), followed by metastatic adenocarcinoma, with 52 cases (5.6%). The concurrent cell block was available in 796 cases. Among them, 574 (72.1%) contained sufficient tissue for diagnosis. Combining analysis of cytologic and histologic specimens, the sensitivity of ultrasound-guided FNA for diagnosis of liver tumors was 85.1% and the specificity 98.7%. The results were better than isolated cytologic analysis, which gave a sensitivity of 78.4% and specificity of 97.4%. The lower diagnostic accuracy of cytology resulted mainly from its lower ability to distinguish well-differentiated HCC from benign lesions. In the cell block sections with reticulin stain, all HCCs showed a decreased or absent reticulin pattern, whereas all the benign hepatocellular lesions usually had a normal trabecular reticulin framework. CONCLUSION: FNA cytology assisted by cell block examination can be an accurate and minimally invasive method for the definitive pathologic diagnosis of primary benign and malignant liver masses and for confirmation of tumors metastatic to the liver. In addition, reticulin staining should be part of the routine assessment of cell blocks. It enhances diagnostic accuracy, particularly for well-differentiated HCC.     

Fine needle aspiration cytodiagnosis of Hodgkin's disease and its subtypes. I. Scope and limitations

The fine needle aspiration (FNA) smears and paraffin-embedded sections from 89 cases with a cytologic and histologic diagnosis of Hodgkin's disease (HD) and 27 cases with minor or major cytohistologic discrepancies were reviewed. The accuracy of the initial cytologic study was found to be 91.8% for diagnosing HD and 58.1% for classifying its subtypes. Following review, 87 of the 89 agreement cases remained classified as HD. Of the 27 cases with initial cytohistologic discrepancies, 12 were classified as HD and 10 were categorized as lymphocytic or non-Hodgkin's lymphoma by both cytology and histology upon review. Following review, the accuracy of FNA cytology for the diagnosis of HD improved to 98.0%, with 71.4% correct subtyping. The greatest limitation of cytologic subtyping was in cases of nodular sclerotic HD: only 3 of 17 cases could be subtyped even after review. The cytomorphologic features of the HD subtypes are described, and the difficulties encountered in the cytodiagnosis of HD are discussed at length. The results of this study indicate that FNA cytology is a useful tool not only for the diagnosis of HD, but also for its subtyping.     

Fine needle aspiration biopsy in uveal melanoma

Fine needle aspiration (FNA) biopsies were performed in a series of patients with uveal tumors. Cytopathologic examination established the correct diagnosis in 26 of 29 uveal melanomas. FNA biopsy was able to exclude the diagnosis of a malignant neoplasm in five nonmelanoma tumefactions. Histologic and FNA cytologic typing of melanomas as epithelioid or predominantly spindle cell showed good agreement, with the same classifications made in 14 of 18 cases. FNA biopsy specimens also proved to be adequate for DNA-content and cell-cycling studies. The cessation of cell cycling in successfully irradiated melanomas may be useful in establishing the postradiation status of tumors that have questionable growths after therapy, as was shown using FNA samples in three such cases in this study. The results of this study show that FNA biopsy is a useful diagnostic adjunct in patients with atypical lesions that require therapy.     

Fine needle aspiration of the liver and pancreas with ultrasound guidance

The experience of the Institut Gustave-Roussy in the diagnosis of hepatic and pancreatic lesions by fine needle aspiration (FNA) is reported. Totals of 116 consecutive percutaneous ultrasound-guided FNAs of the liver and 27 of the pancreas were performed without complication in patients with ultrasonically suspected neoplastic lesions. In 12 cases, the material was not suitable for diagnosis. In the liver, 97 cases were correctly diagnosed and confirmed by follow-up. Immunohistologic studies were helpful in distinguishing primary liver tumors from other malignancies. One false-positive result was reported. In the pancreas, malignancy was detected in 17 cases. Cytology alone provided the correct tumor diagnosis in 15 cases: 10 primary carcinomas, 2 endocrine tumors and 3 metastases. The sensitivities of FNA in this study were 87.6% for the liver and 85% for the pancreas, similar to those reported in other series.     

Diagnostic pitfalls in the fine needle aspiration of thyroid nodules. A study of 555 cases in Chinese patients

The diagnostic value and limitations of fine needle aspiration (FNA) were determined by examining 555 palpable thyroid nodules in Chinese patients who had a definitive diagnosis established by thyroidectomy (529 cases) or large-needle biopsy (26 cases). Of the aspirates, 97.8% were satisfactory for cytologic examination. The overall malignancy rate was 20%. FNA detected 73 (74.5%) of 98 primary malignant tumors and 9 (90%) of 10 metastatic tumors. Diagnostic errors were most commonly due to inadequate specimens and cystic lesions. Cystic fluid, present in one-third of all lesions, was associated with a malignant nodule in 13% of the cases. FNA was most valuable for detecting papillary carcinomas; it may at times suggest the likelihood of a follicular carcinoma.     

Fine needle aspiration cytology of pulmonary carcinoid tumors

Twenty-four cases coded as pulmonary carcinoid tumors initially sampled by fine needle aspiration (FNA) biopsy were reviewed in order to determine the cytologic features most useful in making the FNA diagnosis. The diagnosis of carcinoid tumor had been confirmed in 23 cases; the remaining case, though closely resembling a carcinoid tumor on the FNA specimen, proved to be a sclerosing hemangioma of the lung. Comparison of the original and review interpretations of the FNA specimens revealed that all typical spindle cell carcinoids and all atypical carcinoids were correctly diagnosed and classified. Of the 15 typical round cell carcinoids, the original cytologic diagnosis was lymphoma in 2 cases and benign bronchial lining cells in 2 cases. Thus, it appears that diagnostic errors are most likely in "typical" carcinoids. Review of the FNA findings suggests that the frequently stripped cytoplasm (with resulting non-cohesive bare nuclei), coupled with the almost universal plexiform vascularity (seen in 21 of 23 cases), should allow an accurate cytologic diagnosis in virtually all cases.     

Fine needle aspiration cytology of neuroblastoma, including peripheral neuroectodermal tumor, with immunocytochemical and ultrastructural confirmation

Eleven fine needle aspiration (FNA) biopsies were performed on seven children with neuroblastoma, including one patient with a congenital neuroblastoma and another with a peripheral neuroblastoma of the thoracopulmonary region. FNA cytology made the primary diagnosis of neuroblastoma in four of the seven cases. The other biopsies documented local recurrences and metastases to liver, lymph nodes, orbit and breast. The cytologic features included varying numbers of small primitive cells with scanty cytoplasm, poorly to well-formed pseudorosettes, cell processes, a fibrillary matrix and multinucleated ganglion cells. Five of the seven patients had electron microscopic (EM) examination of the FNA specimen, which in all cases confirmed the diagnosis. Batteries of immunoperoxidase stains were performed on all 11 aspirates with variable results. Staining for neuron-specific enolase was positive in four of the five neoplasms tested, although strongly positive in only three of the cases. Staining for neurofilament markers was positive in only two of five tumors. Studies for cytokeratin markers (AE1/3), low-molecular-weight cytokeratin (35BH11), hematopoietic markers (T29/33), immunoglobulin light chains and myoglobin were negative. One case was positive for vimentin. This study attests to the value of FNA cytology in suggesting a correct diagnosis of either primary, recurrent or metastatic neuroblastoma in children. Selective use of immunoperoxidase stains and EM on the aspirates may be of value.     

Clinicopathologic management of tumors of the thyroid gland in an endemic goiter area. Combined use of preoperative fine needle aspiration biopsy and intraoperative frozen section

In total, 15,325 fine needle aspiration (FNA) biopsies of the thyroid were examined in the Department of Pathology of the University of Innsbruck, Austria, between 1976 and 1985, with the cytologic results histologically verified in 3,112 cases. Since (1) it is frequently impossible to distinguish benign from malignant encapsulated follicular thyroid tumors by cytologic criteria and (2) there is a high level of follicular thyroid carcinoma in our endemic goiter area, we have adopted a diagnostic strategy that accepts a high percentage of false-positive cytologic results in order not to miss highly differentiated follicular carcinoma. To avoid unnecessarily extensive surgical treatment, 1,079 intraoperative frozen section examinations of the thyroid were performed in the same time period in (1) patients with preoperative suspicious or positive FNA cytologic findings, (2) cases with suspicious clinical and anamnestic data and (3) tumors with a suspicious macroscopic appearance without preoperative FNA or with negative or unsatisfactory cytologic findings. In 48 cases (4.5%), the frozen section diagnosis had to be revised after examination of paraffin-embedded tissue. An intraoperative false-positive diagnosis was obtained in 3 cases (0.3%) while a false-negative diagnosis was made in 45 cases (4.2%). The main effort in examining frozen sections should be concentrated on avoiding false-positive errors, which can lead to unnecessary thyroidectomies.     

Fine needle aspiration biopsy versus sputum and bronchial material in the diagnosis of lung cancer. A comparative study of 168 patients

A group of 168 consecutive lung cancer patients in whom a definitive diagnosis of primary lung cancer was established either in a conventional cytologic specimen of sputum or bronchial material or in a specimen obtained by fine needle aspiration (FNA) biopsy was reviewed to compare the relative accuracies between the modalities of sputum and bronchial material on one hand versus FNA cytology on the other in the diagnosis of lung cancer. The patients included in the study were selected from a total of 1,093 patients who had been diagnosed and treated for lung cancer at Duke University Medical Center over the five-year period of January 1, 1980, through December 31, 1984. In 325 (29.8%) of the 1,093 patients, a definitive cancer diagnosis was established from histopathologic study alone, without any cytologic diagnoses. In 420 patients (38.4%), both histologic and cytologic material had been interpreted as being conclusively diagnostic for lung cancer. In 348 patients (31.8%), a cytologic diagnosis of lung cancer was made without a histologic confirmation. Thus, in a total of 768 (70.3%) of the 1,093 cases, a definitive cytologic diagnosis of cancer had been made. Of these 768 patients, 168 had been evaluated by both conventional respiratory cytologic methods (examination of sputum and bronchial material) and with FNA biopsy cytology. In 9 patients (5.4%), only conventional respiratory cytologic specimens were conclusively diagnostic for cancer. In 122 patients (72.6%), only the FNA biopsy specimen was diagnostic. In 37 patients (22.0%), both conventional respiratory specimens and FNA specimens yielded a definitive lung cancer diagnosis. The FNA specimen was the only positive cytologic specimen in 90.2% of large cell undifferentiated carcinomas, 79.5% of adenocarcinomas, 66.7% of small cell undifferentiated carcinomas and 58.2% of squamous cell carcinomas. In 26.5% of the patients, a diagnosis of cancer could have been established on conventional cytologic specimens, without the necessity of proceeding to percutaneous FNA biopsy. From this study, it is concluded that the techniques of conventional respiratory cytology and FNA biopsy cytology are complementary in the diagnosis of lung cancer. While the percentage of lung cancers diagnosed by FNA biopsy cytology alone is much greater than that obtained by conventional respiratory cytology alone, more than one-fourth of these cancers could be detected by the less invasive techniques of sputum collection and bronchoscopy.     

Utility of CD34 reactivity in evaluating focal nodular hepatocellular lesions sampled by fine needle aspiration biopsy

OBJECTIVE: To determine the patterns of CD34 reactivity in hepatocellular adenoma and focal nodular hyperplasia and to evaluate the utility of CD34 reactivity in the diagnosis of hepatocellular carcinoma. STUDY DESIGN: Seventeen cases of well-differentiated hepatocellular carcinoma, 14 cases of cirrhosis, 9 cases of focal nodular hyperplasia and 7 cases of hepatocellular adenoma were stained with immunoperoxidase antibodies to CD34. The slides were scored according to the degree of lesional reactivity. RESULTS: Fourteen of 17 cell blocks with hepatocellular carcinoma showed unequivocal sinusoidal or peripheral reactivity for CD34. Five of seven cases of hepatocellular adenoma and four of nine cases of focal nodular hyperplasia showed > 50% sinusoidal reactivity for CD34. All 14 cases of cirrhosis showed peripheral to no sinusoidal reactivity. CONCLUSION: CD34 reactivity in a diffuse sinusoidal pattern can be helpful in the diagnosis of hepatocellular carcinoma. However, consideration should be given to the possibility of hepatocellular adenoma and focal nodular hyperplasia, which can also exhibit significant diffuse CD34 reactivity. In these cases, a reticulin stain may be helpful with the differential diagnosis.     

Fine needle aspiration biopsy of hepatocellular carcinoma and hepatocellular nodular lesions: role,controversies and approach to diagnosis

A. Wee
Fine needle aspiration biopsy of hepatocellular carcinoma and hepatocellular nodular lesions: role, controversies and appr oach to diagnosis The role of fine needle aspiration (FNA) biopsy of the liver has evolved. Advances in imaging modalities have obviated the need for tissue confirmation in clinically classic hepatocellular carcinoma (HCC). The risks of needle tract seeding and haematogenous dissemination have been actively debated. Nowadays, cytopathologists are confronted by smaller and smaller nodules, detected due to increased surveillance of high‐risk cirrhotic patients. Tissue characterization of small well‐differentiated hepatocellular nodular lesions (size less than and equal to 2 cm) is extremely challenging and has therapeutic implications. Major issues in the cytodiagnosis of HCC include: (i) distinguishing benign hepatocellular nodular lesions, namely, large regenerative nodules, dysplastic nodules, focal nodular hyperplasia and hepatocellular adenoma from reactive hepatocytes; (ii) distinguishing well‐differentiated HCC from benign hepatocellular nodular lesions; (iii) distinguishing poorly differentiated HCC from intrahepatic cholangiocarcinoma and metastatic carcinomas; (iv) determining the histogenesis of a malignant tumour; and (v) determining the site of origin of a malignant tumour. An overview of the biological evolution and histopathological aspects of dysplastic nodules, small HCCs and ‘nodule‐in‐nodule’ lesions is presented in tandem with clinically relevant nomenclature. An algorithmic approach to FNA diagnosis of HCC and hepatocellular nodular lesions is outlined. Optimal results depend on (i) a dedicated radiologist‐cytopathologist team; (ii) an on‐site cytology service, (iii) a combined cytohistological approach, (iv) immunohistochemistry, and (v) clinicopathological correlation. As we move towards personalized medicine, it is envisaged that hepatic FNA is likely to become a point of care in the management protocol as it takes on the additional role of procurement of tumour and peritumoural tissues for genomic and proteomic profiling to enable targeted molecular therapy.     

Fine needle aspiration (FNA) of testicular germ cell tumours; a 10-year experience in a community hospital

garcía-solano j., sánchez-sánchez c., montalbán-romero s., sola-pérez j. and pérez-guillermo m. (1998) Cytopathology 9, 248–262
Fine needle aspiration (FNA) of testicular germ cell tumours; a 10-year experience in a community hospital
A retrospective reappraisal is made of the smears of 29 testicular germ cell tumours (TGCT) studied by FNA in which both orchiectomy specimens and histologic diagnoses were available. In 22 cases (75.86%) the yield was sufficient and contained cells suitable for cytologic diagnosis; in these 22 cases a diagnosis of malignancy was reached. In four cases (13.79%) the yield was sparse and diagnostic cells were partially obscured by haemorrhage and necrosis; these cases were categorized as suspicious of malignancy. In three cases (10.34%) the yield was not suitable for cytologic evaluation because haemorrhage and necrosis hampered evaluation of diagnostic cells. The cytologic findings that enable a reliable diagnosis of TGCT are described and those cytologic features that may lead the less experienced cytopathologist into an erroneous diagnosis are discussed. Pure TGCT can be confidently diagnosed with FNA and mixed TGCT can be successfully diagnosed, although it is difficult to recognize every cytologic subtype observed in the histologic sections. Despite the advantages of FNA for the prompt diagnosis of TGCT, FNA can not fully replace the histologic diagnosis and should rather be considered as a helpful tool in the work-up of testicular tumours.     

Fine needle aspiration biopsy of hepatic focal fatty change. A report of two cases

BACKGROUND: In rare instances, hepatic steatosis produces a circumscribed, nodular lesion described as focal fatty liver change (FFLC). The ultrasonographic and computed tomographic patterns are those of an isointense or hyperechoic nodule, sometimes simultating metastasis. CASES: Fine needle aspiration biopsy was performed under ultrasonographic control in two men aged 65 and 67 years who had previously undergone emicolectomy and gastrectomy for adenocarcinoma. Routine hepatic ultrasound showed solitary nodules, of 3 and 4 cm in diameter. The microscopic patterns were similar and highly cellular in both cases. Cells were isolated or organized in sheets and characterized by large, intracytoplasmic, clear vacuoles that displaced nuclei to the periphery of the cells, flattening them against the cytoplasmic membrane and giving these cells a signet-ring appearance. Nuclei were generally round and nucleolated or dense and hyperchromatic when flattened onto the cytoplasmic membrane. Normal hepatocytes were interspersed in the background, and in some areas of the slides hepatocytes with one or more small intracytoplasmic vacuoles with cytologic features intermediate between those of vacuolated cells and normal hepatocytes were present. Digested periodic acid-Schiff staining, performed on destained, fixed smears, gave negative results. The cytologic diagnosis was FFLC. Clinical and echographic follow-up confirmed the cytologic diagnosis. CONCLUSION: The ultrasonographic and microscopic features of FFLC may mimic those of metastasis. A proper cytologic diagnosis may contribute to the diagnostic workup of these rare lesions.     

Conclusive diagnosis of hepatic and pancreatic malignancies by fine needle aspiration

A study of the diagnosis of hepatic and pancreatic malignancies by fine needle aspiration (FNA) was made, based on 221 aspirates obtained from 209 patients with histologic or clinical confirmation: 159 with hepatic and 50 with pancreatic lesions. The values of sensitivity, specificity and predictivity for positive FNA results were, respectively, 0.84, 0.96 and 1.0 for the liver and 0.76, 1.0 and 1.0 for the pancreas. The composition of the case material showed an incidence of malignant tumors of the liver and pancreas of 84% and 60%, respectively (among which the primary malignancies were 39% and 48%), while nonneoplastic lesions had incidences of 14% and 40%. However, conclusive FNA diagnoses of the histologic type of the primary and the site of origin of metastatic tumors were made in 60% of the hepatic lesions but in only 9% of the pancreatic lesions. Primary hepatocellular carcinoma was diagnosed by FNA of the liver in 95% of the cases; FNA specifically diagnosed 42% of intrahepatic bile duct carcinomas and 40% of hepatic metastases. These findings correlate with the unique cytologic features of primary hepatocellular carcinoma of intrahepatic rather nonspecific morphology of carcinoma of intrahepatic and extrahepatic origin, as well as of pancreatic ductal origin.     

Fine needle aspiration cytology of malignant mesothelioma

The results of fine needle aspiration (FNA) cytology in 19 cases of malignant mesothelioma are presented. Adequate material for a diagnosis of malignancy was obtained in 17 cases, and in 8 cases a specific diagnosis of mesothelioma could be made. In four other cases, the findings were either consistent with or suggestive of mesothelioma; in four, accurate distinction from other neoplasms was not possible, and in two cases, adenocarcinoma was suggested. The spectrum of cytologic findings ranged from neoplasms of purely epithelial appearance through more pleomorphic biphasic neoplasms to anaplastic tumors. A combination of epithelial-like cell clusters, pavement-like sheets of epithelial cells with well-defined cell borders and prominent cell separation, dispersed angular cells with dense cytoplasm and some spindle-cell forms was the most specific cytologic pattern for mesothelioma. In four neoplasms, ultrastructural examination of aspirated material provided the additional evidence for a definitive diagnosis. The identification of hyaluronic acid within intracytoplasmic vacuoles, either in smears or in cell blocks, confirmed the diagnosis in three tumors. Only in one case, with a strong clinical background suggesting mesothelioma, was the cytologic preparation sufficient for diagnosis without ancillary diagnostic methods. FNA is of particular value in the diagnosis of pleural mesothelioma in patients who do not present with a pleural effusion. Obtaining material for cell block preparations, cytochemistry or ultrastructural study is generally necessary for definitive tumor typing.