Fine needle aspiration of the thyroid. Distinction between colloid nodules and follicular neoplasms using cell blocks and 21-gauge needles

Although fine needle aspiration (FNA) of the thyroid has been found to be useful in selecting patients for surgery in most cases, the cytologic differentiation of cellular colloid nodules from follicular neoplasms has not been possible because of the scanty amount of tissue obtained by this technique and because of the infrequent preparation of cell blocks, thus precluding appreciation of the tissue architecture. Review of the histology of nodular goiters and follicular neoplasms and comparison of their morphology in smears and cell blocks from FNA specimens with the histology of the surgically excised specimens in 74 cases revealed the presence of hyperplastic papillae and fragments of dilated follicles in the aspirates of most cases of colloid nodules. These two features appear to be specific for colloid nodules and are useful for distinguishing colloid nodules from follicular neoplasms. The merits of using a 21-gauge needle and of preparing cell blocks in thyroid studies are also discussed.     

Fine needle aspiration cytology diagnosis of a cutaneous granular cell tumor in a 7-year-old child. A case report

BACKGROUND: Granular cell tumors are neoplasms of uncertain histogenesis, although a neural origin is favored. Most reports on the cytologic features of granular cell tumors have been on lesions from the breast or respiratory tract. However, there are only a few reports on fine needle aspiration (FNA) cytologic diagnosis of cutaneous or soft tissue granular cell tumors. CASE: A 7-year-old girl presented with a skin lesion on her right forearm of one year's duration. The FNA smears showed sheets and clusters of oval to polygonal cells with an abundant amount of granular cytoplasm. Many single, scattered cells with similar morphology were seen in the background. Immunostaining for S-100 protein showed granular cytoplasmic positivity. The tumor was diagnosed as a benign granular cell tumor. The histopathology report on the excised lesion confirmed the FNA diagnosis. CONCLUSION: The cytopathologic features of granular cell tumors presenting as skin lesions are distinctive enough to allow a correct diagnosis on FNA cytology.     

Benign follicular thyroid lesions versus follicular variant of papillary carcinoma: differentiation by architectural pattern

Differentiation between benign and malignant follicular lesions is one of the difficult diagnostic areas in thyroid fine needle aspiration (FNA). Nuclear criteria are usually used to distinguish between them. In this study the microarchitectural pattern of common benign follicular lesions, namely nodular hyperplasia (NH) and follicular adenoma (FA) were analysed in comparison with those of follicular variant of papillary carcinoma (FVPC) in order to aid in their differentiation. The FNA smears of histologically proven cases of FVPC, NH and FA were reviewed and compared. The microarchitectural features of FVPC, NH and FA were described. Three cytological features--multi-layered rosettes, branching monolayered sheets and balls of thick pinkish colloid--were exclusively observed in FVPC. Hyperplastic papillae with intact follicles and colloid were frequently seen in NH, 83% and 100%, respectively. Albeit less frequently, they were also noted in FVPC, 25% and 75% of cases, respectively. These overlapping features make the distinction between FVPC and NH sometimes difficult; however, assessing the smears for the specific features of FVPC may help in their differentiation. None of the aforementioned microscopic findings with the exception of the seldom presence of colloid were documented in FA. The crowded clusters of follicular cells were seen both in FA and FVPC; however, they were complex and branching in the latter and round to oval in the former. Finally, smears with good recovery of material are indispensable for the identification of these helpful microarchitectural patterns.     

Papillary breast lesions diagnosed on cytology. Profile of 65 cases

OBJECTIVE: To analyze the cytologic features of nipple discharge and fine needle aspiration (FNA) cytologic smears from breast lesions reported as showing papillary features and to correlate them with histopathologic features. STUDY DESIGN: The study group consisted of FNA smears and/or nipple discharge smears from 65 breast lesions diagnosed on cytology as duct papilloma, papillary lesion, fibrocystic condition, fibroadenoma, papillary neoplasm or papillary carcinoma. Cytomorphologic features assessed included cellularity, cell pattern (clusters, papillary, 3-dimensionality, etc.) and cell characteristics (monomorphism, pleomorphism, apocrine change, plasmacytoid features). Histological material was available for review and cytohistologic correlation in all cases. RESULTS: Forty-six specimens were FNA smears, and 16 were nipple discharge smears; in 3 cases FNA and nipple discharge cytologic smears were available for review. Cytologic study could predict the presence of a papillary pattern in all neoplasms with pure or focal papillary differentiation. There was an overlap in cytomorphologic features between papillary and nonpapillary benign lesions as well as between benign and malignant papillary neoplasms. Frank blood in the aspirate, cell dissociation and atypia, however, were more frequent in the last. CONCLUSION: Overlap of cytologic features in nonneoplastic and neoplastic benign papillary lesions and between benign and malignant papillary neoplasms necessitates histologic evaluation in all cases diagnosed as papillary on cytology. Since 49.2% of lesions showing papillary features on cytology prove to be malignant, all cases reported as papillary on cytology should be excised urgently for histologic assessment.     

Cytoplasmic colloid inclusions in thyroid lesions: a cytomorphological study based on fine needle aspiration

INTRODUCTION: Intracytoplasmic lumens (ICL) with or without magenta material and transgressing vessels are features of Hürthle cell neoplasms (HCN). After detection of intracytoplasmic colloid inclusions (CIs) including targetoid (magenta) body-like structures in the Hürthle cells (HC) in a case of Hashimoto's thyroiditis (HT), we reviewed cases of HT, thyroid neoplasms, hyperplastic nodules (HN) and colloid goitres to determine the frequency of these structures. Further, an attempt was made to find out the significance of CIs. METHODS: FNA smears of 120 HT, 101 colloid goitres, 11 HN, and 76 neoplastic goitres were examined. The presence of CIs and empty ICL were noted in epithelial cells in these lesions. An attempt was made to find out the difference between HT with and without CIs in respect of various cytomorphologic features. The groups were compared using the Fisher's exact test of probability. RESULTS: The CIs were present in 36 (30.0%) of HT, 26 (34.2%) of neoplastic goitres, 3 (27.3%) of HN, and 4 (4.0%) colloid goitres. As compared to colloid goitres, CIs were present in a significant higher number of cases in HN (P = 0.0202), neoplastic goitres (P < 0.0001), and HT (P < 0.0001). Among neoplasms the frequency of CIs in HCN (75.0%) was significantly higher than that of papillary thyroid carcinoma (PTC) (33.3%, P = 0.0466), and follicular neoplasm (14.3%, P = 0.0083). The CIs were more frequent in HC in HT and HCN but in follicular cells (FC) in other lesions. The HT cases with CIs differed significantly from those without CIs in respect of HC and their cellularity, cellularity of reactive lymphoid cells, extracellular colloid and empty ICL. CONCLUSION: Care should be taken not to diagnose HT cases with an excessive Hürthle cell component and CIs, and PTC cases with Hürthlization and CIs, as HCN in FNA smears. Based on review of the literature and our findings, it is suggested that the Hürthle cell metaplasia in HT is a survival response of FC and the presence of CIs in Hürthle cell may represent their limited ability to synthesize colloid.     

Aspiration cytology of Hashimoto's thyroiditis in an endemic area

Fine needle aspiration (FNA) plays a significant role in the diagnosis of thyroid lesions due to its simplicity and low cost. Hashimoto's thyroiditis (HT) is the second most common thyroid lesion next to endemic goitre diagnosed on FNA in iodine (I2) deficient areas. Data on its incidence, prevalence and clinicopathological features in I2 deficient areas is scanty compared to I2 sufficient areas. In the present study the patients presented with HT a decade earlier than reported in I2 sufficient areas. Presentation as a nodular thyroid is common. Diagnosis of HT is likely to be missed in smears showing cytological evidence of hyperplasia or abundant colloid. HT was concurrent in 20 cases of endemic goitre. Careful screening for Hurthle cell change and lymphocytic infiltration into follicular cells should be carried out. In equivocal cases multiple punctures and immunological investigations are helpful. In antibody-negative cases repeat FNA at follow-up is useful. Marked lymphocytic infiltration and Hurthle cell change may indicate a hypothyroid state but hormonal levels are required for clinical management.     

Fine needle aspirates of follicular lesions of the thyroid gland. The intermediate-type smear

In order to evaluate fine needle aspirates of thyroid lesions with features intermediate between those of follicular neoplasms and colloid nodules, 38 aspirates in which a definitive diagnosis had not been made were reviewed. On review, ten aspirates were excluded from the "intermediate" category; seven were reclassified as unsatisfactory and one as a cellular colloid nodule. Two papillary carcinomas showed a complex pattern not identified in smears from other lesions; these aspirates were also classified separately for independent evaluation. The remaining 28 aspirates were characterized by syncytial-type tissue fragments with mild nuclear atypia. The association of syncytial-type tissue fragments and orderly sheets and fragments forming a honeycomb pattern in the same aspirate indicated a colloid nodule, though a two-disease process could not be excluded. Of the aspirates containing only syncytial-type tissue fragments, 50% were from adenomas, 25% were from carcinomas, and 25% were from colloid nodules. Criteria to distinguish between the various follicular lesions were not identified in these smears.     

Solitary nodular goiter. Review of cytomorphologic features in 441 cases.

OBJECTIVE: To study the cytomorphologic features of solitary nodular goiters (SNG). STUDY DESIGN: May-Grünwald-Giemsa-stained smears in 441 SNG diagnosed by ultrasonography and fine needle aspiration (FNA) and found to have optimum cellular material at review were subjected to detailed cytologic assessment. The age of the patients ranged from 11 to 75 years, with a median of 35. Male: female ratio was 69:372. The parameters for cytologic assessment included cellularity, colloid content, acinar formation, papillary formation, intranuclear cytoplasmic inclusions, nuclear grooves, marginal vacuoles, Hürthle cells and various inflammatory cells. Histopathology reports on thyroidectomy specimens were available in 27 cases from two Delhi hospitals. RESULTS: Hyperplastic nodules (68 cases) differed significantly from colloid goiters (269 cases) by having more cases with excessive cellularity, acinar formation and marginal vacuoles (P < .001). There was also a significant difference with respect to papillary formation and moderate-to-excessive colloid content (P < .001). As compared to hyperplastic nodules, neoplasms (60 cases) had a significantly higher number of cases with papillary formation, intranuclear inclusions and nuclear grooves but lower number of cases with marginal vacuoles (P < .01-.001). Among neoplasms, usual papillary carcinoma (19 cases) differed from follicular neoplasms (20 cases) with respect to acinar formation, papillary formation and nuclear grooves (P < .001). A significant difference was also observed with respect to colloid content and nuclear inclusions. Follicular variant of papillary carcinomas (FVPC) (10 cases) emerged as a distinct cytologic entity following review and differed from usual papillary carcinomas in having a higher number of cases with acinar formation, tubular formation and marginal vacuoles (P < .01-.001) and lower number of cases with nuclear grooves (P = .05). FVPC also differed from follicular neoplasms with respect to papillary formation, tubular formation, intranuclear inclusions and nuclear grooves (P < .01-.001). Overall cytohistologic agreement was achieved in 24 of 27 (88.9%) cases. CONCLUSION: Detailed cytologic assessment of FNA smears-in SNG was helpful in highlighting parameters that differentiate between various types of goiters.     

Galectin-3 is not useful in thyroid FNA

INTRODUCTION: Previous studies have suggested that galectin-3 immunohistochemistry may be useful in the fine needle aspiration (FNA) diagnosis of thyroid carcinoma as it has been reported to selectively stain carcinomas and not adenomas or goitres. METHODS: Fifty-one patients were included in a prospective study of galectin-3 in thyroid FNA; 88.2% were female and 11.8% male, mean age 53 years, range 25-87 years. Cell blocks were prepared and stained for galectin-3 if any cells were present in needle washings from the respective FNAs. RESULTS: Twelve of 51 (23.5%) of cell blocks contained epithelial cells. One benign and one inadequate FNA were negative for galectin-3 staining. One of five non-diagnostic FNA cases, a papillary carcinoma on final histology showed positive staining. Four follicular neoplasm/suspicious of carcinoma cases showed negative staining. One malignant FNA case, a papillary carcinoma showed positive staining with galectin-3 but three further carcinomas, two papillary and one follicular were galectin-3 negative. CONCLUSION: Galectin-3 immunohistochemistry does not appear to be a useful adjunct to diagnosis in thyroid FNA as it does not reliably distinguish malignant and benign lesions. Many thyroid aspirates are of low cellularity and are not suitable for cell block immunohistochemistry.     

Diagnostic utility of galectin-3 in aspirates of thyroid follicular lesions

OBJECTIVE: To investigate the expression of galectin-3 in various thyroid follicular lesions, including diffuse hyperplasia, nodular hyperplasia, and benign and malignant follicular neoplasms, to clarify the diagnostic utility of galectin-3 in aspirates of follicular lesions. STUDY DESIGN: A total of 146 follicular lesions diagnosed cytologically, obtained from patients who had undergone thyroidectomy for either benign or malignant nodules, were evaluated using Papanicolaou-stained slides and cell blocks with galectin-3 immunostaining. We primarily categorized the aspirated specimens as benign, indeterminate or suspicious for a follicular neoplasm based on cellularity, architectural arrangement of the follicular cells and presence or absence of colloid. Galectin-3 immunostaining was evaluated according to the proportion and intensity of positively stained cells. Cytologic diagnoses were correlated with the results of galectin-3 and categorized into 3 groups (benign, indeterminate for malignancy, suspicious for malignancy) and compared with the corresponding histologic diagnoses. RESULTS: When the histologic diagnoses were compared with the cytologic diagnoses, the accuracy in the distinction between benign and malignant cases was 79.5% except for 8 cytologically and 3 histologically indeterminate cases. Except for 11 indeterminate cases, there were 18 (12.3%) discrepant cases. False positive cases included 8 of 62 (12.9%) nodular hyperplasias and 1 of 42 (2.4%) follicular adenomas. Of 9 false negative cases, 4 minimally invasive carcinomas and 2 widely invasive carcinomas were included. Three follicular tumors of uncertain malignant potential were cytologically categorized as malignant, and all cases showed positivity for galectin-3. CONCLUSION: Galectin-3 could be used as a useful supplementary marker for cytologic diagnosis, although it was not an absolute marker in determining whether a lesion was benign or malignant.     

Fine needle aspiration of metastatic and hematologic malignancies clinically mimicking pancreatic carcinoma.

The fine needle aspiration (FNA) cytology findings in 19 cases of hematopoietic and metastatic neoplasms that radiographically mimicked primary pancreatic carcinoma are reported. These cases represented 11% of 176 malignant diagnoses in a series of 304 pancreatic FNAs. The cytologic diagnoses included 7 non-Hodgkin's lymphomas, 2 Hodgkin's lymphomas, 6 small cell carcinomas (4 lung, 1 gallbladder, 1 skin), 3 squamous cell carcinomas (2 cervix, 1 esophagus) and 1 hepatocellular carcinoma. In six cases the pancreatic lesion was the initial presentation of malignant disease. These included five lymphomas, which probably involved peripancreatic lymph nodes, and a metastatic small cell carcinoma of pulmonary origin. Recognition of unusual morphologic features of pancreatic carcinoma raised the possibility of extrapancreatic malignancies. Electron microscopy and immunocytochemistry performed on FNA specimens were helpful in selected cases. The FNA diagnosis of hematopoietic and metastatic neoplasms that clinically mimic pancreatic carcinoma prompts appropriate clinical studies and treatment and eliminates the need for open pancreatic biopsy and/or resection.     

Use of a thin-layer technique in thyroid fine needle aspiration

OBJECTIVE: To investigate the efficacy of the ThinPrep Processor (Cytyc Corporation, Boxborough, Massachusetts, U.S.A) in fine needle aspiration (FNA) of thyroid gland lesions. STUDY DESIGN: This study included 459 thyroid FNA specimens obtained from patients who came to our endocrinology department with various thyroid disorders over 3 years. The cytologic material was prepared using both the conventional and ThinPrep method in the first 2 years (285 cases), while in the last one only the ThinPrep method was used (1 74 cases). The smears were stained using a modified Papanicolaou procedure and May-Grünwald-Giemsa stain. Immunocytochemistry was performed on thin-layer slides using specific monoclonal antibodies when needed. Thin-layer and direct smear diagnoses were compared with the final cytologic or histologic diagnoses, when available. RESULTS: Our cases included 279 adenomatoid nodules, 15 cases of Hashimoto thyroiditis, 45 follicular neoplasms, 14 Hürthle cell tumors, 58 papillary carcinomas and 1 5 anaplastic carcinomas. Thin-layer preparations showed a trend toward a lower proportion of inadequate specimens and a lower false negative rate. Cytomorphologic features showed some differences between the 2 methods. Colloid was less frequently observed on ThinPrep slides, while nuclear detail and micronucleoli were more easily detected with this technique. Moreover, ThinPrep appeared to be the appropriate method for the use of ancillary techniques in suspicious cases. CONCLUSION: Thin-layer cytology improves the diagnostic accuracy of thyroid FNA and offers the possibility of performing new techniques, such as immunocytochemistry, on the same sample in order to detect malignancy as well as the type and origin of thyroid gland neoplasms.     

Fine needle aspiration cytology of follicular dendritic cell sarcoma. A case report

BACKGROUND: Follicular dendritic cell (FDC) sarcoma is a rare, recently described neoplasm that shows differentiation similar to that of follicular dendritic cells. It must be differentiated from metastatic neoplasms and other rare, nonlymphoid nodal lesions. CASE REPORT: A 76-year-old man underwent fine needle aspiration of a recurrent laterocervical mass. Sixteen months earlier, the original tumor was excised and proved to be an FDC sarcoma. Smears exhibited a dual cell population composed of large cells with abundant cytoplasm and a lymphoid component that consisted mainly of lymphocytes and plasma cells. Large cells were atypical and distributed in ill-defined groups and as single cells. Nuclei were round to oval and pleomorphic, with irregular contours and nucleoli. Binucleation and multinucleation were occasionally seen. After the cytologic diagnosis, the tumor was excised and showed typical histologic and immunophenotypic features of FDC sarcoma. CONCLUSION: The morphologic features of FDC sarcoma seem characteristic enough to permit its preoperative recognition. Its cytologic definition increases our knowledge of rare, nonlymphoid, primary nodal tumors, allowing better differentiation from metastatic neoplasms.     

Psammoma bodies in fine needle aspirates from thyroids containing nontoxic hyperplastic nodular goiters

Psammoma bodies present in fine needle aspiration (FNA) smears with typical cytologic features of colloid goiter from five patients raised the possibility of coexistent papillary carcinoma. However, subsequent careful histologic examination of the entire thyroidectomy specimens did not show occult carcinoma in any of the cases. The psammoma bodies were identified in the stroma next to the foci of papillary hyperplasia in each case. They were small, often equal in size to or slightly larger than the follicular epithelial cell nuclei, and could be misinterpreted as epithelial cell nuclei. These findings suggest that the presence of psammoma bodies in an FNA smear cytologically consistent with a colloid goiter should raise the possibility of coexistent papillary hyperplasia or neoplasia. However, because of the strong statistical association of psammoma bodies with malignant thyroid neoplasms, histologic confirmation is mandatory in such cases.     

The role of FNA in the initial management of thyroid lesions: 7-year experience in a district general hospital

Fine needle aspiration (FNA) cytology plays a major role in the diagnosis of the thyroid lesions in university hospitals and tertiary referral institutions. Our aim was to find out if this was possible in small district hospitals with limited resources. Over a 7-year period, from October 1994 to April 2002, 303 patients with thyroid swellings underwent FNA with an overall adequacy rate of 97.7%. FNAs were performed specifically by the pathologists, so that our inadequacy rate, 2.3% was far lower than 11-29% reported elsewhere. The FNA findings were compared with subsequent histology results in 67 cases. The diagnosis of benign and neoplastic lesions was predicted accurately by FNA in 93% and 94.7% of cases, respectively. The latter reached 100% if results of FNA in follicular neoplasms were excluded. Sensitivity and specificity were 85.6% and 97.6%, respectively, which is comparable with results from tertiary institutions. The commonest thyroid lesions in our hospital were nodular goitre (52.4%), followed by thyroiditis (17.6%) and neoplasia (13.9%). We conclude that, with the availability of appropriate personnel, FNA is feasible as the major modality in district general hospitals. FNA in follicular lesions remains challenging but could be overcome in part by recognizing the criteria to differentiate follicular variant of papillary carcinoma and other follicular proliferations. Aspiration, smearing, staining and interpretation should be left to pathologists or other well-trained personnel to ensure good quality and consistency.     

Thoracic fine needle aspiration biopsy versus fine needle cutting biopsy. A comparative study of 40 patients

The fine needle aspiration (FNA) biopsy findings were compared with the results of fine needle cutting (FNC) biopsy in 40 patients. The lesions (38 pulmonary nodules, 1 mediastinal mass and one lytic rib lesion) were biopsied with 22-gauge Greene and 21-gauge E-Z-EM needles through a 19-gauge needle guide. The FNA biopsy findings were based on smears and cell blocks of material obtained with the Greene needles while the FNC biopsy findings were based on tissue cores obtained by the E-Z-EM needles. In 83% of the cases, both techniques yielded specimens with similar cellularity; in seven cases, the FNA samples were more cellular. Malignancy was diagnosed in 80% of the patients: by both techniques in 26 patients, by FNA biopsy only in 5 patients and by FNC biopsy only in 1 patient. The sensitivity of FNA biopsy was higher than that of FNC biopsy (96.8% vs. 84.3%). The specificity and predictive value of positive results were 100% for both techniques. The predictive value of negative results was higher for FNA biopsy (88.8% vs. 54.5%). The majority of FNC biopsy tissue cores consisted mostly of clotted blood, lung tissue and/or fibrous tissue and did not facilitate or improve the diagnosis. Those data suggest that the contribution of FNC biopsy to the diagnosis of thoracic neoplasms is very limited and that the performance of FNC biopsy with an E-Z-EM needle in addition to or instead of FNA biopsy is not justified.     

Can abundant colloid exclude oncocytic (Hürthle cell) carcinoma in thyroid fine needle aspiration? Cytohistological correlation of 127 oncocytic (Hürthle cell) lesions

Objective:  The objective of the present study was to find out whether the presence or absence of certain cytological features can exclude oncocytic (Hürthle cell) carcinoma in thyroid fine needle aspiration (FNA) to minimize unnecessary surgery. Methods:  Over a 17‐year period, 127 hypercellular, oncocyte‐exclusive, lymphocyte‐absent aspirates obtained via ultrasound‐guided FNA with on‐site assessment had histology slides for review. The presence or absence of six cytological features (microfollicular arrangement, discohesive single cells, small cell dysplasia, large cell dysplasia, transgressing blood vessels and colloid) and one histological feature (macrofollicular component) were determined for each case independently by two cytopathologists. Results:  Histology showed 12 (9.4%) cases of Hashimoto thyroiditis, 23 (18.1%) oncocytic adenomatoid nodules in nodular goitre, 66 (52.0%) oncocytic adenomas and 26 (20.5%) oncocytic carcinomas (13 minimally invasive without angioinvasion, six minimally invasive with angioinvasion, seven widely invasive). Histologically, a macrofollicular component was present in seven of 26 (26.9%) oncocytic carcinomas, including one case with abundant thin colloid. A microfollicular arrangement, discohesive single cells, small cell dysplasia, large cell dysplasia and transgressing vessels were present in oncocytic carcinoma, oncocytic adenoma and oncocytic adenomatoid nodules in nodular goitre. Conclusions:  A macrofollicular component is frequently present in oncocytic carcinoma, oncocytic adenoma and oncocytic adenomatoid nodules in nodular goitre. None of the cytological features studied, including abundant colloid, can exclude oncocytic carcinoma. Oncocytic carcinoma can only be excluded by thorough histological examination of thyroidectomy specimens. A molecular marker is needed to triage oncocytic lesions in thyroid FNA.     

Application of the immunoperoxidase technique to cell block preparations from fine needle aspirates

Immunocytochemistry on fine needle aspiration (FNA) material has been mainly performed on cytologic preparations; there have been few reports on the use of FNA cell blocks. This study compared the intensity scores of immunoperoxidase staining on FNA cell block preparations from 21 breast, 12 thyroid and 10 lymph node aspirates with the scores on the corresponding surgically excised specimens. FNA materials for cell blocks were fixed in formalin and embedded in agar. Ten commercially available antibodies forming three panels were studied using standard peroxidase-antiperoxidase and avidin-biotin complex techniques. In general, the staining results on the FNA cell block sections agreed with those on the surgical specimens; in addition, there were fewer aberrant positive staining results and much less background staining in the cell block sections. These phenomena were most striking with the cytokeratin antibodies. It is concluded that immunoperoxidase staining on FNA cell block preparations is reliable; the advantages of the use of cell block sections as opposed to smears are discussed.     

Value of fine needle aspiration cytology of the breast, with an emphasis on the cytodiagnosis of colloid carcinoma.

The fine needle aspiration (FNA) cytologic evaluation of 6,941 lesions of the breast was reviewed, with an emphasis on the cytodiagnosis of colloid carcinoma. The most common benign breast diseases in this series were fibroadenomas, cysts and fibrocystic conditions. All cases with an FNA diagnosis of suspicious were biopsied; a number of these were found to be carcinoma of the breast. In cases with an FNA diagnosis of carcinoma of the breast, a plan of management was immediately adopted on the basis of that diagnosis. Thirteen cases of colloid (mucinous) carcinoma of the breast were diagnosed by FNA cytology; in all, the cytodiagnosis was confirmed by the subsequent histologic diagnosis. The distinctive cytologic criteria that may be useful for making an FNA diagnosis of colloid carcinoma of the breast are discussed, and the FNA differences between the pure and mixed types of colloid carcinoma are noted.