Silver Binding Nucleolar Organizer Regions In Adrenocortical Neoplasia

The possible contribution of the silver colloid technique for staining nucleolar organizer regions in the distinction between benign and malignant adrenocortical neoplasms was investigated. Nine cases of adenoma, eight cases of carcinoma, nine cases of hyperplasia and four normal adrenal cortex specimens were examined. The mean silver binding nucleolar organizer region (Ag-NOR) value in adenoma was 4.29, and in carcinoma 7.16 (P less than 0.001). Adenomas with diameters greater than 3 cm had significantly higher Ag-NOR counts than smaller adenomas. For normal cortex, the mean Ag-NOR value was 2.05 and in hyperplasia, 3.62. The results indicate that the Ag-NOR technique can help in differential diagnosis between benign and malignant adrenocortical lesions and thus may have a prognostic value.     

Cytodiagnosis of 112 salivary gland lesions. Correlation with histologic and frozen section diagnosis.

Aspirates of 112 cases of salivary gland lesions with histologic correlation were reviewed. Fifty-five cases (49%) had frozen sections made. The 112 cases included 76 cases of benign lesions (31 cases of pleomorphic adenoma, 19 of Warthin's tumor and 26 of nonneoplastic lesions), 22 of primary salivary gland malignancy and 14 of metastatic malignant lesions. The overall accuracy in diagnosing benign and malignant lesions was 95%. The accuracy in diagnosing the exact category of neoplastic lesions was 70%. The diagnostic sensitivity for malignant lesions was 86% and the specificity, 99%. There was one false positive, in which a pleomorphic adenoma was diagnosed as small cell carcinoma. Five false-negative cases were encountered that were due to underdiagnosis of mucoepidermoid carcinoma and adenoid cystic carcinoma. The smears were reviewed, and the diagnostic pitfalls are discussed. A comparison of the cytodiagnosis and frozen section diagnosis was made. In frozen sections there were two false negatives, and two diagnoses were deferred. The overall diagnostic accuracy was 91%. The accuracy in diagnosing the exact category of neoplastic disease was 77%. The diagnostic sensitivity for malignant disease was 70% and specificity, 100%. Frozen section, however, did supplement the fine needle aspiration diagnosis in 13 cases.     

Posters. P19 Cervical carcinoma with metastases to the tympanic membrane: an unusual presentation

Introduction Fine needle aspiration (FNA) is a well‐established diagnostic technique which is frequently used to diagnose head and neck neoplasms. Clinical decisions concerning treatment of malignant salivary gland tumours, the extent of surgery and advisability of pre‐operative irradiation can be helped by prior knowledge of tumour type. Aim The aim of this study was to do an audit of all salivary gland FNAs carried out in Beaumont Hospital over a 14‐year period. Methods All salivary gland FNAs between 1989 and 2002 were reviewed. Where available, the corresponding follow‐up histological specimens were studied. Results During this 14‐year period, 305 patients with salivary gland lesions had FNA of the lesion performed. The total number of aspirates performed was 343. Of these, 184 had histologies available for follow‐up. Eighty‐nine aspirates were reported as inadequate; 89 as inflammatory, normal or consistent with cyst contents. One hundred and thirteen aspirates were diagnosed as a benign entity. Thirty‐three aspirates were reported as malignant (21 of which were felt to be primary to the salivary gland and 12 metastatic). Sixteen cases were called suspicious. Good correlation between FNA findings and histology was seen in the majority of cases (145 of 183). Some diagnostic problem areas were identified. These included the following: lymphomas (seven called benign on FNA), Warthin's tumour (seven not diagnosed or misdiagnosed on FNA) and mucoepidermoid carcinoma (one reported as pleomorhic adenoma and one as benign/cystic on FNA). Seven pleomorphic adenomas were not diagnosed on FNA pre‐operatively, predominantly due to inadequacy of the specimen. Three other malignancies (acinic cell carcinoma, lymphoepithelial carcinoma and carcinoma ex‐pleomorphic adenoma), while not diagnosed on FNA, were called suspicious, with re‐biopsy advised. Conclusion FNA cytology of salivary glands is an accurate method for evaluation of both benign and malignant lesions, enabling optimum surgical and adjuvant therapy decision‐making pre‐operatively. Well‐defined problem areas are identified and, therefore, clinicopathological correlation is required in these cases.     

AgNOR quantification in the diagnosis of follicular pattern thyroid lesions

OBJECTIVE: To evaluate the usefulness of silver staining of nucleolar organizer regions (AgNORs) in the preoperative diagnosis of follicular lesions in the thyroid with computer-aided morphometric analysis of the silver dots. STUDY DESIGN: Forty-eight cytologic smears of the thyroid were divided into 3 groups according to the results of postoperative histopathologic examination: hyperplastic nodules in nodular goiter (NG) (20), follicular thyroid adenoma (FTA) (20) and follicular thyroid carcinoma (FTC) (8). They were silver stained. The slides were analyzed with a computerized system for image analysis. Nearly 20 variables describing AgNORs were calculated (related to the area of the dots, number of dots and intranuclear localization of the dots). RESULTS: Only assessment of the total area of AgNORs in the nucleus allowed distinguishing between malignant and benign lesions. It was possible to determine the cutoff value of the total area of AgNORs in the nucleus (3.00 microns 2), limiting FTC from other lesions (observed ranges: NG, 1.64-2.87 microns 2; FTA, 1.81-2.85 microns 2; FTC, 3.01-3.97 microns 2). Evaluation of the mean number of AgNORs per nucleus did not improve the diagnosis of malignancy. CONCLUSION: Computer-aided morphometric analysis of silver dots may be useful in the preoperative diagnosis of thyroid lesions.     

Polyploidy In Pleomorphic Adenomas With Cytological Atypia

Occasionally, in fine-needle aspirates of pleomorphic salivary gland adenomas, considerable cytonuclear atypia is present, which may give rise to a false-positive diagnosis. In this study DNA cytophotometry was performed on Feulgen restained smears prepared from material obtained by needle aspirates of normal salivary glands (n = 4), pleomorphic adenomas with (n = 5) and without (n = 4) atypia and a carcinoma in a pleomorphic adenoma. The results showed a clear diploid DNA histogram in the specimens of normal salivary gland and pleomorphic adenomas without atypia. In contrast, in the pleomorphic adenomas with atypia a distinct polyploid pattern was present in three out of the five DNA histograms with DNA values in 2c, 4c and 8c ranges. In two of these cases a 16c peak was also present and in the two remaining cases tetraploidy was demonstrated. In the carcinoma a main stemline at 4c was found. This report once more emphasizes the possible atypia which may be present in FNA of pleomorphic adenomas of the salivary gland. The atypia is due to polyploidy in a histologically benign tumour.     

Cytologic findings of a pleomorphic adenoma of the breast: a case report

BACKGROUND: Pleomorphic adenoma of the breast is a rare benign tumor. Only a few cases have been reported. The histologic features have been described well. However, the cytologic findings have been described in only a few papers. CASE: A 47-year-old female presented with a left breast mass of several months' duration. The clinical and mammographic findings were highly suspicious for malignancy. Following an aspiration biopsy diagnosis of "positive for malignancy," the mass was excised. The histologic diagnosis was pleomorphic adenoma (mixed tumor of salivary gland type) rather than carcinoma. CONCLUSION: The cytologic presentation of pleomorphic adenoma of the breast can masquerade as that of a malignant tumor, in this case colloid carcinoma. This case delineates the cytomorphologicfeatures of pleomorphic adenoma, which may mimic carcinoma.     

Split sample comparison of a liquid-based method and conventional smears in thyroid fine needle aspiration

OBJECTIVE: To compare the efficacy of the SurePath (SP) vs. conventional smears (CS) in fine needle aspiration (FNA) of thyroid gland lesions. STUDY DESIGN: A total of 193 FNA cases with thyroid nodules were studied. Samples from ultrasound-guided FNA were split to prepare CS and SP slides. The diagnostic categories of unsatisfactory, benign, atypical and malignant were compared. Galectin-3 immunostaining was performed on SP slides. RESULTS: Some differences were found between the cytomorphology of CS and SP. SP slides showed more increased cellularity and more clustered tissue fragments. On SP slides, nuclear detail and nucleoli were more easily detected and nuclear irregularity was very useful for the diagnosis of papillary carcinoma. SP showed a trend toward a lower proportion of atypical category. The overall sensitivity of FNA in diagnosing thyroid neoplasm was 90.9% for CS and 93.9% for SP. Most lesions (73%) diagnosed as papillary carcinoma after surgery showed positive staining of galectin-3. CONCLUSION: The SP method showed easy evaluation of cytomorphologic features and consistent specimen quality and appeared to be more useful in diagnosing the suspicious cases. Moreover, it offered the possibility of adjunctive immunocytochemistry on the same sample.     

Role of fine needle aspiration cytology in diagnosis of pleomorphic adenomas

Role of fine needle aspiration cytology in diagnosis of pleomorphic adenomas This retrospective study was carried out to review the cases diagnosed as pleomorphic adenoma in major or minor salivary glands and determine the difficulties encountered on typing this tumour on fine needle aspiration cytology (FNAC). Over a 19‐year period (1982–2000) 488 pleomorphic adenomas were diagnosed on FNAC from different sites (parotid – 372 cases, submandibular – 95 cases; oral cavity – 21 cases). Histology was available in 232 cases. Twenty‐nine cases where a histological diagnosis of pleomorphic adenoma was made but the cytological diagnosis was variable were also reviewed. In 216 of the 232 cases a good cytohistological correlation was available. On review only 4 of the 16 cases initially diagnosed as pleomorphic adenoma on FNAC where the histology revealed a different tumour were categorized as pleomorphic adenoma, while 3 each were classified as adenoid cystic carcinoma and benign tumour ?type, and 2 each were diagnosed to be muco‐epidermoid carcinoma, monomorphic adenoma and acinic cell carcinoma. On review of the FNAC smears from 29 cases where a histological diagnosis of pleomorphic adenoma was available while the cytological diagnosis was variable, only 11 (38%) were categorized as pleomorphic adenoma. In the majority of the remaining cases the cytological diagnosis did not alter markedly, 7 of 10 cases where the tumour could not be typed on cytology initially could not be typed even on review. In conclusion, FNAC is an ideal, fairly accurate preoperative procedure for the diagnosis of pleomorphic adenomas. Certain diagnostic problems occur in differentiating pleomorphic adenomas from adenoid cystic carcinoma, monomorphic adenoma and mucoepidermoid carcinoma. Carcinoma ex‐pleomorphic adenoma is difficult to identify on FNAC and in our series all 4 such cases on histology were considered benign on cytology.     

R3: Invasive salivary duct carcinoma ex pleomorphic adenoma of the parotid gland: a teaching case giving rise to the genuine diagnostic difficulty on an inadequate cytology specimen

ABSTRACT: A history of a recent rapid increase in long-standing swelling mass was presented in the right parotid gland of an 85-year-old male. The inadequate cytologic specimens contained few small clusters of three-dimensional malignant epithelial cells having hyperchromatic pleomorphic nuclei and prominent nucleoli, adjacent to a cluster of benign monomorphic myoepithelial cells. We first interpreted it merely as an adenocarcinoma, not otherwise specified. A radical parotidectomy was performed, and gross examination revealed an encapsulated and firm tumor lesion, looking grayish-blue to yellowish-white, focally associated with extracapsular invasion. On microscopic examination, the tumor was predominantly composed of a proliferation of highly atypical epithelial cells having abundant eosinophilic cytoplasm, often arranged in a Roman-bridge appearance with foci of comedo necrosis, alternating with extensive infiltration to adjacent stroma in a trabecular or alveolar fashion with severe vessel permeation. Within the background of pleomorphic adenoma, the carcinoma cells sometimes replaced ductal luminal cells while retaining an intact-like myoepithelial layer. Therefore, we finally made a diagnosis of invasive salivary duct carcinoma ex pleomorphic adenoma. We should be aware that owing to its characteristic features, cytopathologists might be able to determine correct diagnosis, based on multiple and adequate samplings. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2126158270695815.     

Proliferative activity as detected by immunostaining with Ki-67 and proliferating cell nuclear antigen in benign and malignant epithelial lesions of the human parotid gland

OBJECTIVE: A retrospective immunohistochemical study of parotid gland lesions was designed to evaluate the diagnostic and prognostic value of the proliferating cell nuclear antigen (PCNA) and Ki-67 with monoclonal antibodies PC 10 and MIB-1, respectively. STUDY DESIGN: Tissue samples comprised normal parotid gland (N, n = 10), chronic sialadenitis (CS, n = 8), Warthin's tumor (W, n = 10), benign pleomorphic adenoma (BPA, n = 8), mucoepidermoid carcinoma (MEC, n = 13), carcinoma in pleomorphic adenoma (CPA, n = 8) and adenoid cystic carcinoma (ACC, n = 12). The morphometric parameters for PCNA and MIB-1 comprised the PI and MI labelling indices (the numerical percentage of positive nuclei), NAP and NAM (the numerical density of positive nuclei), and NPI and NMI (volume corrected index). RESULTS: The values of MIB-1 parameters increased progressively in benign lesions in comparison with the N group and in malignant neoplasms in comparison with nonneoplastic groups and benign lesions. Values for all parameters in BPA were significantly lower than those in malignant groups. Spearman rank correlation analysis showed a highly positive correlation between the morphometric parameters and severity of the lesions. The mean values of MI and NMI were significantly higher in patients who died of the malignant tumors than in those who survived. The same quantitative parameters for PCNA did not differ significantly from those obtained for MIB-1 and showed similar trends. CONCLUSION: PCNA and MIB-1 indices are reliable markers for discriminating between benign and malignant tumors of the parotid gland, and the parameters PI, MI, NPI and NMI may have prognostic applications.     

Intravenous pyogenic granuloma mimicking pleomorphic adenoma in a fine needle aspirate. A case report.

BACKGROUND: Intravenous pyogenic granuloma (IvPG) is a rare, benign lesion occurring usually as a subcutaneous mass in the neck or upper extremity. The cytologic features of IvPG have not been described before. CASE: A patient presented with a subcutaneous nodule on the lower border of the left parotid area. The clinical diagnosis was bronchial cleft cyst or lymphadenitis, and the fine needle aspiration diagnosis was pleomorphic adenoma. The tissue section, however, disclosed IvPG. CONCLUSION: Evaluation of subcutaneous nodules presenting cytologically as spindle cell lesions may be problematic, particularly in the neck and head region. Such lesions occurring in the parotid area may be interpreted as pleomorphic adenoma of the salivary gland.     

Cytomorphologic spectrum of carcinoma ex pleomorphic adenoma

OBJECTIVE: To delineate the cytomorphologic features of carcinoma ex pleomorphic adenoma (CPA) and identify the diagnostic pitfalls. STUDY DESIGN: Smears of 14 cases suspected as CPA on fine needle aspiration over a period of 15 years were reviewed. Cytohistologic correlation was done in 10 cases. RESULTS: All cases had a salivary gland mass of 1-16 years' duration, with a rapid increase in size in 10 cases. Epithelial cells predominated over stroma in 11 of 14 cases. Group I showed unequivocal malignant cells admixed with benign epithelial and stromal components of pleomorphic adenoma (PA), which were considered diagnostic of CPA on review. The cytologic differential diagnosis in these cases included mucoepidermoid carcinoma, carcinosarcoma and metastatic adenocarcinoma. Group II comprised 7 cases suspected to be cellular PA with atypia or CPA. These showed mild to moderate degrees of pleomorphism, absence of unequivocal malignant cells, and a variable proportion of benign epithelial and stromal components. Four of them were histologically confirmed as CPA. CONCLUSION: Sampling error is an important cause of diagnostic pitfalls. Correlation with clinical data is essential in diagnosis of CPA on cytology. In a proper clinical setting, extensive fine needle aspiration sampling should be done initially. Any degree of nuclear atypia in PA should be documented, alerting the clinician and histopathologist to the possibility of CPA.     

Benign neurilemmoma (schwannoma) masquerading as a pleomorphic adenoma of the submandibular salivary gland

A case of solitary benign neurilemmoma (schwannoma) arising in the submandibular region is presented. The tumor was mistaken clinically for an enlarged submandibular salivary gland. Fine needle aspiration cytology made an erroneous diagnosis of a pleomorphic adenoma, predominantly stromal in composition. Histology of the resection specimen resulted in the correct diagnosis of a benign schwannoma. Review of the needle aspirate demonstrated cytologic features that should enable both the correct diagnosis of this neoplasm and its distinction from pleomorphic adenoma, which it mimicked in this location.     

Epithelial myoepithelial carcinoma of the parotid gland with malignant ductal and myoepithelial components arising in a pleomorphic adenoma: a case report with cytologic, histologic and immunohistochemical correlation

BACKGROUND: To describe the cytologic, histologic and immunohistochemical findings of a case of epithelial myoepithelial carcinoma (EMC) arising from a pleomorphic adenoma (PA) of the parotid with both malignant epithelial and myoepithelial components. CASE: A 29-year-old female presented with a 1.5 x 1.5-cm, palpable mass of the left parotid of 7-8 months' duration with recent enlargement and pain. Fine needle aspiration biopsy (FNAB) revealed biphasic epithelial (small cell) and myoepithelial (large/clear cell) clusters arranged in a pseudopapillary and trabecular pattern with abundant hyaline material with many naked nuclei, together with areas typical of pleomorphic adenoma (PA) was noted. The cytology was reported as salivary gland neoplasm, "suggestive of adenoid cystic carcinoma, less likely pleomorphic adenoma." The mass was excised and histologically reported as "pleomorphic adenoma, with focal invasion of one resected margin." Four months later the tumor recurred, and FNAB showed almost the same cytologic features as did the previous aspirate. Due to early recurrence, previous histologic sections were reviewed, and typical areas of a biphasic pattern of EMC with atypicality and mitosis of both components was found. The final diagnosis was EMC ex PA. CONCLUSION: Although previous reports mention the difficulties in diagnosing EMC and differentiation from the more common salivary gland neoplasms such as PA, we like to emphasize the cytologic confusion that results when the tumors coexist.     

Cytopathology and diagnostics of Warthin's tumour

Warthin's tumour (WT) is a benign epithelial salivary tumour, one type of salivary adenoma. Histologically, WT is structured of two components, epithelial tissue that often lines cystic formations and lymphoid tissue in the tumour stroma. FNA is a reliable diagnostic approach in the diagnosis of salivary gland lesions allowing a highly accurate categorization of benign tumour‐like lesions, benign tumours and malignant tumours. In the proposed Milan reporting system of salivary gland lesions, WT is categorized in the IVA group of benign neoplasms. Accurate cytological diagnosis is straightforward when three characteristic components are present: oncocytes, either isolated or associated in clusters, lymphocytes and lymphoid cells and often an inflammatory/necrotic‐like substance. Also, specific features of scintigraphy and radiological imaging contribute to the diagnosis of WT. WT is categorized according to Seifert G. et al in 4 types, depending on the proportions of the epithelial component and lymphoid stroma. Differential cytopathological and pathohistological diagnosis include other salivary gland lesions with lymphoid, oncocytic epithelial and cystic components. In some cases, such as the metaplastic WT variant, there are additional cytopathological and histological diagnostic difficulties. Moreover, bilateral, multicentric or multiple and infrequently seen extra‐salivary localizations of WT are associated with further cytopathological diagnostic difficulties. Also, a rare possibility of malignant transformation of the epithelial or lymphoid component of WT as well as possible association with other primary tumours remains a challenge in accurate cytopathological and histological diagnosis of WT.     

Clear cell carcinoma arising from pleomorphic adenoma of a minor salivary gland: Report of a case with fine needle aspiration, histologic and immunohistochemical findings

BACKGROUND: Malignant changes in pleomorphic adenoma (PA) of the salivary gland (carcinoma ex pleomorphic adenoma) are not common. Clear cell carcinoma is a rare form of salivary gland tumor and involves mostly minor salivary glands, especially those of the palate. Only 3 cases of clear cell carcinoma arising in PA have been reported, 2 in submandibular glands and 1 in a minor salivary gland of the palate. CASE : A 53-year-old man presented with an enlarged mass on the left side of the palate. He had a history of palate mass about 30 years earlier; it was excised and reported as PA. Since then the tumor had recurred twice in the same place; it had been excised and was diagnosed as PA again. A few years later the mass showed rapid growth over a few months. Fine needle aspiration of the mass showed epithelial clusters with bland nuclear features and myxohyaline material typical of PA. Also noted were large and small papillary, trabecular and well-circumscribed clusters of neoplastic cells with a moderate amount offoamy, vacuolated cytoplasm with distinct borders. Glandlike and acinar structures with hyaline globule material resembling cannonballs were also noted. The cytology was suspicious for malignancy. Incisional biopsy was reported as PA. Due to the suspicion of malignancy, the whole mass was excised up to the floor of the orbit. The final diagnosis was clear cell carcinoma expleomorphic adenoma. CONCLUSION: Due to nonspecific cytologic findings in clear cell carcinoma and a mixture of elements of PA in this case, we did not consider clear cell carcinoma as the malignant component.     

Diagnostic efficacy of immunocytochemistry on fine needle aspiration biopsies processed by thin-layer cytology

OBJECTIVE: To evaluate the efficacy of immunocytochemistry (ICC) performed on smears processed by thin-layer cytology (TLC). STUDY DESIGN: During the period January 2001-September 2003, 3,573 consecutive fine needle aspiration biopsies were processed with both conventional smears (CSs) and TLC diagnosed by a single pathologist; 113 required immunocytochemical study. CSs were fixed in ethanol whereas TLC slides were processed with the ThinPrep 2000 method (Cytyc Co., Marlborough, Massachusetts, U.S.A); both were stained with Papanicolaou stain. ICC staining was carried out on only TLC slides. RESULTS: The 113 cytologic cases were grouped as follows: 32 thyroid nodules with 16 histologic controls (HCs), 24 lymph nodes (regardless of location) with 15 HCs, 18 liver and pancreatic lesions (3 HCs), 11 lung nodules (6 HCs), 5 kidney and adrenal gland lesions (1 HC), 6 abdominal (2 HCs) and 4 mediastinal masses (1 HC), 6 salivary gland tumors (3 HCs), 4 bone masses (2 HCs) and 3 subcutaneous lesions (1 HC). ICC contributed to the diagnosis in 104 cases (92%), whereas it was inconclusive in 9. The cytologic diagnoses were histologically confirmed in 46 of 50 cases (92%). CONCLUSION: ICC can be successfully applied on TLC slides with better results than on CSs, and its yield can be useful in making the correct diagnosis on fine needle aspiration biopsy.     

Polymorphous low grade adenocarcinoma of the salivary gland. Diagnosis by fine needle aspiration cytology

OBJECTIVE: To describe the fine needle aspiration cytology findings of polymorphous low grade adenocarcinoma of the salivary gland. STUDY DESIGN: The authors reviewed the cytologic findings of 5 cases of polymorphous low grade adenocarcinoma. All cases were confirmed by histologic examination. RESULTS: All cases showed similar cytologic findings. The smears had high cellularity with a population of mixed epithelial and myoepithelial cells. These cells formed branching papillae, sheets and clusters. The epithelial cells were uniform, with round to ovoid nuclei; absent or inconspicuous nucleoli; and a moderate amount of dense cytoplasm. Occasionally the cells formed spherical structures containing hyaline globules. Myxoid matrix, either dispersed in the background or interspersed with the cellular elements, was also seen often. CONCLUSION: Polymorphous low grade adenocarcinoma should be cytologically differentiated from adenoid cystic carcinoma, monomorphic adenoma and pleomorphic adenoma. Recognition of subtle cytologic features. may be useful in the differential diagnosis.     

Low grade mucoepidermoid carcinoma arising in cervical lymph nodes. A report of two cases with fine needle aspiration findings

BACKGROUND: Heterotopic islands of salivary tissue are commonly found in the intraparotid lymph nodes and, less commonly, within extraparotid cervical nodes. Salivary gland tumors, both benign and malignant, can develop within this ectopic salivary tissue. CASES: Two patients presented with a solitary, painless mass in the cervical region. Fine needle aspiration cytology was performed, and the smears revealed a mixture of intermediate and mucus-secreting cells associated with extracellular mucin. The tumors were removed, and the diagnosis of mucoepidermoid carcinoma was confirmed by histologic study. CONCLUSION: The finding of a malignant cervical salivary gland tumor does not necessarily represent a metastasis from an occult site.     

Coexpression of Vimentin, Cytokeratin and S-100 In Monomorphic Adenoma of Salivary Gland; Value of Marker Studies In the Differential Diagnosis of Salivary Gland Tumours

An unusual coexpression of glial fibrillary acid protein (GFAP), keratin and vimentin occurs in pleomorphic adenoma of salivary gland. We designed this study to see if coexpression of the markers was also present in monomorphic adenoma of the salivary gland and whether monomorphic adenoma could be distinguished from other salivary gland tumours by marker studies. Immunocytochemical markers were used on fine needle aspiration samples from four cases of monomorphic adenoma, two cases of oncocytic adenoma, three cases of adenoid cystic carcinoma and four cases of pleomorphic adenoma. While positivity for cytokeratin, vimentin and S-100 was consistently found in all cases of monomorphic adenoma, only cytokeratin was expressed in adenoid cystic carcinoma. In pleomorphic adenoma, GFAP, cytokeratin and vimentin were coexpressed while in cases of oncocytic adenoma none of the markers was localized. Thus, it appears that by using a combination of GFAP, cytokeratin, vimentin and S-100 a distinction between these neoplasms may be possible. However, a larger study is needed to establish the usefulness of this approach.