Bioacumulation and ultrastructural effects of Cd, Cu, Pb and Zn in the moss Scorpiurum circinatum (Brid.) Fleisch. & Loeske.

This paper tested if culturing the moss Scorpiurum circinatum (Brid.) Fleisch. & Loeske with metal solutions (Cd, Cu, Pb and Zn) for 30 days causes metal bioaccumulation and ultrastructural changes. The results showed that despite the high heavy metal concentrations in treatment solutions, treated samples did not show severe ultrastructural changes and cells were still alive and generally well preserved. Bioaccumulation highlighted that moss cells survived to heavy metal toxicity by immobilizing most toxic ions extracellularly, likely in binding sites of the cell wall, which is the main site of metal detoxification.

The integrity of lichen cell membrane as a suitable parameter for monitoring biological effects of acute nitrogen pollution.

This study aimed at testing the suitability of cell membrane integrity in the lichen Evernia prunastri (L.) Ach. as sensitive indicator of nitrogen (N) stress, to set up a rapid and effective method for monitoring biological effects of acute N pollution. Lichen samples were incubated in solutions of potassium nitrate, ammonium nitrate and ammonium sulphate at different concentrations, and cell membrane damage, expressed in terms of increased electrolyte leakage, was measured after 0, 24, 48 and 96 h. Cell membrane damage was observed in E. prunastri in the presence of high or very high N concentrations, irrespective of the compound supplied. Since the mycobiont represents the large majority of a lichen biomass, it is reasonable to assume that ion leakage mainly occurred from fungal cells. Although in biomonitoring studies the photobiont is usually regarded as the most sensitive partner of the lichen symbiosis, our findings suggest that the mycobiont is most affected in the case of N-excess, and that this feature can be used as suitable indicator of acute N stress episodes.

Heavy metal deposition in the Italian "triangle of death" determined with the moss Scorpiurum circinatum.

In this study, a biomonitoring project using the moss Scorpiurum circinatum was carried out to evaluate the deposition and biological effects of heavy metals in the area of Acerra (Naples, S Italy), one of the vertices of the sadly called "Italian triangle of death" owing to the dramatic increase in tumours. The results clearly indicated that the study area is heavily polluted by heavy metals, a large proportion of which is likely present in the atmosphere in particulate form. The ultrastructural organization of exposed samples was essentially preserved, but cell membrane pits, cytoplasm vesicles and concentric multilamellar/multivesicular bodies, probably induced by pollution, were found, which may be involved in the tolerance mechanisms to metal pollution in this moss species. Although severe biological effects were not found at the ultrastructural level in the exposed moss, effects on humans, especially after long-term exposure, are to be expected.

Galectin-3 immunodetection may improve cytological diagnosis of occult papillary thyroid carcinoma.

Galectin-3 has been found recently to be neo-expressed in thyroid cancers compared to benign lesions and it could therefore be considered a marker of malignancy. We report the case of a 36-year-old woman with a history of occasional dysphagia and dysphonia first observed in November 2000. Thyroid ultrasound scan revealed two subcentimetric nodules in the right lobe. The larger one underwent ultrasound-guided fine-needle aspiration cytology (FNAC). Due to the nature of the lesion, only a few cells could be collected. Their morphological aspect was suspicious but not conclusive for malignancy, therefore we marked the cells using a monoclonal antibody anti-galectin-3. The cytological suspicions were supported by galectin-3-expressing cells, so the patient was referred to surgery. The final histological diagnosis was conclusive for multifocal occult thyroid papillary carcinomas. We conclude that the galectin-3 immunocytochemical assay should be part of the diagnostic protocol supporting conventional cytology to characterize scanty and/or suspicious cellular smears.

[New and old procedures in the diagnosis of dubious breast lesions]. / Procedure diagnostiche tradizionali e di recente introduzione nelle lesioni mammarie di dubbia interpretazione.

In the last years the detection of early breast cancers (lesions less than one centimetre in diameter, with good prognosis) has consistently increased for the wide application of mammary screening programs. At the same time, an increasing number of radiographically detected unexpected lesions (nonpalpable breast lesions) has been evidenced. In those cases, often both mammography and ultrasound evaluation are dubious and a multidisciplinary diagnostic approach is mandatory. Fine-needle aspiration (FNA) and core biopsy (CB) are well established diagnostic methods but, in recent years, new microinvasive bioptic procedures (as the Mammotome and the ABBI systems) have been introduced. In this review the limits and the possibilities of the classical and new cytohistological techniques are evaluated. A possible multistep diagnostic approach is described on a cost-benefit basis and in consideration of the various procedures.

Immunocytochemical expression of Ki67 and laminin in Hurthle cell adenomas and carcinomas.

BACKGROUND: Hurthle cell neoplasms may occur as a benign adenoma or carcinoma; the latter displays comparatively aggressive clinical behaviour. Fine-needle aspiration cytology (FNAC) represents a reliable tool for screening Hurthle cell lesions before surgery. Nevertheless, the cytological interpretation of these lesions is not always unequivocal. We analyzed cell growth and cellular adhesiveness by means of two different antibodies, Mib1 (Ki67) and laminin. AIM: The aim of the study was to analyze Ki67 and laminin immunocytochemical expression on FNAC to evaluate their usefulness in the preoperative differential diagnosis of Hurthle cell neoplasms. RESULTS: A higher expression of Ki67 has been recorded in malignant lesions as compared to benign ones (8% to 20% vs 1% to 5% nuclear staining, respectively; p < 0.001). An increased reactivity of anti-laminin antibody was recorded in the cytoplasm of cells from all malignant lesions. In Hurthle cell adenomas this adhesion molecule showed an intensity ranging from low to moderate. Moreover, a few benign lesions showing a moderate proliferative activity were associated with evident laminin expression. CONCLUSION: These findings support the hypothesis that benign Hurthle cell lesions with a high cellular proliferation associated with an increased laminin expression could define a subset of lesions prone to malignant transformation. Conversely, since all cases with low expression of both laminin and Ki67 always correspond to adenomas, we suggest that the different expression of these two antibodies on FNAC can provide a further tool for the preoperative identification of lesions at low risk of malignancy, thus avoiding unnecessary surgery.

Thyroiditis and oncocytic carcinoma: incidental association? A case report.

BACKGROUND: Several studies have reported an association between Hashimoto's disease and thyroid carcinoma although the cause/effect relationship is still controversial. CASE REPORT: In this paper we report the case of a 38-year-old female who first presented with a clinical history of Hashimoto's thyroiditis. Ultrasound examination showed a diffuse thyroid irregularity more pronounced in the right lobe. FNAC (Fine Needle Aspiration Cytology) was performed in this area, and the cytological diagnosis was "Hashimoto's thyroiditis". The patient underwent clinical follow-up. Two years later, an ultrasound examination showed a nodular lump in the area previously aspirated. A new FNAC evidenced a Hurthle cell neoplasia. Therefore, the patient underwent surgery. The histological diagnosis was "Hurthle cell carcinoma". CONCLUSION: In the present case, the clinical and ultrasound history suggest the development of a malignant lesion strictly related to thyroiditis, as previously reported by other studies on papillary carcinoma. A cause-effect relationship between chronic lymphocytic thyroiditis and oncocytic neoplasia is still a matter of controversy. Therefore, patients suffering from chronic thyroiditis require a careful follow-up and, in case of nodules development, FNAC is recommended.

Implication of laminin and collagen type IV expression in the progression of breast carcinoma.

BACKGROUND: The prognostic variability in breast cancer patients prompted the authors to investigate specific biological markers for the identification of high-risk breast cancer groups. In the present study, attention was focused on the interaction between tumor cells and the extracellular matrix, an important requisite in the metastatic process. MATERIALS AND METHODS: Fifty-six primary breast carcinoma specimens obtained by mastectomy or quadrantectomy plus axillary dissection were examined with immunohistochemistry, for the determination of laminin, collagen type IV and hormone receptor expression and with static cytometry, for the determination of the DNA content. RESULTS: Laminin and collagen type IV expression was observed on the membrane and in the cytoplasm of neoplastic cells. Laminin and collagen type IV were present, respectively, in 85.4% and 73.8% of the cases which showed recurrence. CONCLUSION: The results of this study have shown that high expression of laminin and collagen type IV may have a value in the prognosis of disease free survival and may be linked to other classical clinical, histological and biological parameters in the evaluation of breast cancer patients.

Cervical dysplasia, ploidy, and human papillomavirus status correlate with loss of Fhit expression.

PURPOSE: The tumor suppressor gene, FHIT, has been cloned and mapped at chromosome region 3p14.2, one of the regions most frequently deleted in cervical carcinoma. In this report, we show that the expression of the Fhit protein in relation to human papillomavirus (HPV) subtype, the type of the intraepithelial lesion, HIV-induced immunodeficiency, and the DNA content (ploidy) correlates with the biological behavior of the lesions. EXPERIMENTAL DESIGN: To investigate involvement of the FHIT gene in squamous intraepithelial lesions of low and high grade (LGSILs and HGSILs, respectively) of the uterine cervix, we examined the Fhit protein expression by immunocytochemistry in 131 cervical smears of 96 HIV-seropositive patients (42 with LGSILs and 10 with HGSILs) and 35 HIV-seronegative (5 with LGSILs) persons. RESULTS: Fhit protein was detected in normal cells, whereas dysplastic cells (independently of HPV infection and HPV subtypes) showed reduced expression of Fhit (P = 0.00001). Lesions from 52 HIV-seropositive patients, 42 LGSILs and 10 HGSILs, showed diploid DNA content in 63.5%, aneuploid in 32.7%, and polyploid in 3.8%, but 90% of the HGSILs showed an aneuploid DNA content, and all were infected by HPV 16/18 subtypes. 23.8% of LGSIL cases were associated with HPV 16. CONCLUSIONS: These data clearly suggest that loss of Fhit expression occurs in the early stages of cervical carcinogenesis. Pap test represents one of the most convenient and rapid procedures available in identification of cellular changes; hence, Fhit staining might be used as an useful tool in larger population screening to detect early alteration in cellular behaviors.

Msh2, Mlh1, Fhit, p53, Bcl-2, and Bax expression in invasive and in situ squamous cell carcinoma of the uterine cervix.

To analyze relevant factors and their effects on neoplastic progression in cervical carcinoma, a panel of genetic markers was studied. Paraffin-embedded tissue sections were obtained from 37 patients with carcinoma of the uterine cervix, 14 noninvasive squamous cell carcinomas (NISCCs), and 23 invasive squamous cell carcinomas (ISCCs). Immunoreactivity of Msh2, Mlh1, Fhit, p53, Bcl-2, and Bax proteins was examined by immunohistochemical staining with appropriate antibodies. Positive staining of Msh2 was detected in 13 of 14 (92.9%) NISCCs and in 13 of 23 (56.5%) ISCCs (P < 0.02). Mlh1 immunoreactivity was observed in 10 of 14 (71.4%) NISCCs and in 8 of 23 (34.8%) ISCCs (P < 0.04). Overexpression of p53 protein was found in 4 of 14 (28.6%) NISCCs and in 16 of 23 (69.6%) ISCCs (P < 0.02). Bcl-2 overexpression was detected in 2 of 14 (14.3%) NISCCs and in 15 of 23 (65.2%) ISCCs (P < 0.003). No significant difference in the two types of lesion was found for Bax and Fhit expression. The relationship between Mlh1, Msh2, and p53 protein expression was significant (P < 0.001 and P < 0.001, respectively), as was that between Fhit and Bax immunoreactivity (P < 0.02). In conclusion, we consider that altered expression of Msh2, Mlh1, p53, and Bcl-2 may be a critical event during cervical cancer progression, whereas Fhit may be a component of a proapoptotic pathway.

Fine needle aspiration and core needle biopsy techniques in the diagnosis of nodular thyroid pathologies.

It is widly accepted that Fine Needle Aspiration Biopsy (FNAB) is the main test to distinguish benign from malignant thyroid lesions. Nevertheless, this technique presents some limits such as the possibility of false-negative or inadequate samples and it is unable to cytologically discriminate among adenomathosus goiter, follicular adenoma and well-differentiated follicular carcinoma. The aim of this study was to evaluate the possibility of restricting these limitations using Core Needle biopsy (CN) technique. Therefore we selected for CN, 40 out of 136 patients who underwent FNAB during a one year period; among these patients only 32 agreed a to this technique. Forty-two out of 136 patients underwent surgery; 29 of them were subjected to both biopsies. Sixteen of the diagnostic microbiopsies have been histologically confirmed. We had no discordant cases between cytological and microhistological diagnosis, except for one case which appeared cytologically colloid goiter, microhistologically follicular neoplasm and histologically follicular adenoma. In this case it was not possible to microhistologically discriminate benign from malign follicular lesion. In our experience not all patients accepted CN biopsy as well as FNAB and, moreover, this technique showed no advantage over FNAB diagnosis. On this base we think that actually FNAB should be the main procedure in the diagnosis of the thyroid lesions. It is easily performed, accepted by the patients and has a low cost-benefit ratio. If the sample is not diagnostic it can be easily repeated and false-negative cases could be discovered thanks to an adequate clinical and ultrasonographical follow-up of the patients.

Cytological and immunocytochemical evaluation of thyroid and breast masses in patients with a previous neoplasm: case reports.

The diagnosis of secondary tumours represents one of the most important fields in the application of fine needle aspiration cytology (FNAC). We studied two patients, one with a history of breast cancer and one with a previous tumour of the thyroid, who showed a second mass, in the thyroid and in the breast, respectively, during follow up. The aim of our study was to evaluate if cytology, performed on FNAC smears, may distinguish a metastatic lesion from a second primary tumour, or if further immunocytochemistry should be performed. Our data demonstrate that, while cytology may be indicative of a second primary tumour, the histotype should be confirmed by immunocytochemical staining.

Tall cell variant of papillary carcinoma coexisting with chronic lymphocytic thyroiditis. A case report.

BACKGROUND: Recent studies have shown a correlation between lymphocytic thyroiditis and papillary carcinoma of the thyroid. It is thought that autoimmune thyroiditis could be a risk factor for the development of thyroid carcinoma, mainly for the papillary variant. CASE: A 59-year-old female presented with a history of enlargement in the neck and five months of dysphagia. Clinical examination showed generalized expansion and an increase in the hardness of the thyroid gland. Hormonal outline showed subclinical hypothyroidism with serum levels of TSH slightly elevated (5 micrograms/dL; range, 0.25-4). Thyroglobulin antibodies and thyroperoxidase titers were moderately positive. Given these results, a diagnosis of chronic thyroiditis was made. Thyroid ultrasound scan showed diffuse gland irregularity and the presence of a solitary nodule (2.3 cm in diameter) localized in the right lobe. Fine needle aspiration biopsy (FNAB) of the nodule was performed under ultrasound guidance. CONCLUSION: Although clinical and laboratory results supported the diagnosis of autoimmune thyroiditis only, FNAB of the nodular lesion provided evidence of a rare case of papillary carcinoma, tall cell variant, confirmed by histologic results.

[Evaluation of cellular proliferative activity and DNA ploidy as a prognostic factor in breast cancer]. / Valutazione dell'attività proliferativa cellulare e della ploidia come fattori prognostici del carcinoma della mammella.

BACKGROUND: In the past years, morphological indexes and kinetic parameters have been introduced to characterize breast cancer in order to select breast cancer patients for adjuvant therapy. The alterations of the proliferative activity of neoplastic cells and DNA ploidy may provide important information about the aggressiveness of the lesion and may be used as powerful prognostic factors. In fact, prognostic information based on the classic clinico-pathologic parameters such as histotype, stage and grade are no longer sufficient to select patients for long term follow-up. The aim of this study was to evaluate the malignant potential of neoplastic cells through the determination of modifications of the proliferative index and the evaluation of DNA ploidy. METHODS: Forty-five breast cancer patients, 32 to 80 years of age, were studied. Proliferative indexes and DNA ploidy, besides the other clinical-pathologic parameters have been evaluated. The proliferative index was assessed with the immunocytochemical determination of Ki67 and quantified with the CAS 200: 31 cases had a high proliferative index, 12 medium and 2 low. DNA ploidy was analyzed on cytologic preparations with static cytometry utilizing an image analyzer CAS 200: 13 cases were diploid, 32 non-diploid. RESULTS: A close relationship was found between Ki67 expression and DNA ploidy. In fact, lesions with a high proliferative index were all non-diploid, whereas, those with a low proliferative index were all diploid. Lesions with a medium proliferative index were 2 diploid and 1 non-diploid. Among the 45 cases, studied in a follow-up period of 36 months, 12 showed disease recurrence; 3 showed a medium Ki67 expression and were diploid, 9 a high Ki67 expression and were all non-diploid. CONCLUSIONS: In conclusion, proliferative indexes and DNA ploidy may be considered additional prognostic parameters which may potentially influence the clinical behaviour of breast cancer and may be utilized besides all the other clinico-pathologic data to assess these lesions.

DNA ploidy and TLI in association with other prognostic parameters in breast cancer.

DNA ploidy and thymidine-labeling index (TLI) have been introduced as prognostic indicators to characterize the biological behavior of breast cancer for the selection of patients eligible for adjuvant therapy. The aim of this study was to evaluate the prognostic significance and correlation between ploidy status, TLI and other common histopathologic parameters such as histotype, stage, grading, lymph node metastasis, hormone receptors and recurrence. DNA ploidy and TLI were assessed for 68 breast cancer patients, 27 to 85 years of age. DNA histograms, analyzed with static cytometry, were: diploid in 21(31%) and non diploid in 47 (70%). High TLI values were observed in 16 cases (24%), medium values in 46 cases (68%) and low values in 6 cases (8.5%). DNA ploidy and TLI showed a statistically significant correlation, as independent parameters, with recurrence (respectively, p = 0.0267 and p < 0.0001). Therefore, DNA ploidy and TLI may be considered additional prognostic parameters to be utilized besides all the other clinical-pathologic data for the assessment of these lesions, and to plan therapeutic strategies.

Reference standardization and analytical performance of a liquid homogeneous high-density lipoprotein cholesterol method compared with chemical precipitation method.

BACKGROUND: The use of high-density lipoprotein cholesterol (HDL-C) levels as a risk factor for coronary heart disease necessitates an accurate and precise method for measuring HDL-C. The Centers for Disease Control and Prevention HDL-C reference method (RM) and designated comparison method (DCM) are time-consuming, expensive, and impractical for routine clinical use. We evaluated the Liquid N-geneous (LN-gen) HDL-C assay (Genzyme Diagnostics, Cambridge, Mass) to determine if this homogeneous reagent meets the National Cholesterol Education Program requirements for HDL-C evaluation. DESIGN: Accuracy of the LN-gen HDL-C assay was compared in combination with phosphotungstic acid (PTA) precipitation with DCM HDL-C for normotriglyceridemic serum specimens (triglycerides < 2.0 g/L) and with RM HDL-C for specimens with triglycerides levels > or = 2.0 g/L. SETTING: Genzyme Diagnostics (with RM and DCM assayed by Pacific BioMetrics Inc, Seattle, Wash) and the Lipid Reference Laboratory of the University Hospital Rotterdam, The Netherlands. RESULTS: Linear regression to DCM (n = 90) was (LN-gen = 1.015 DCM + 0.01 g/L, r = 0.993, SE = 0.015 g/L) and (PTA = 1.004 DCM - 0.017 g/L, r = 0.980, SE = 0.025 g/L), with a mean percent bias to DCM of 3.3% and -2.8% for LN-gen and PTA, respectively. The comparison with RM (n = 69) showed an increased mean bias for PTA (-5.8%) as compared with LN-gen (1.5%). The correlation and regression equations were (LN-gen = 1.020 RM - 0.002 g/L, r = 0.985, SE = 0.017 g/L) and (PTA = 1.042 RM - 0.032 g/L, r = 0.984, SE = 0.018 g/L). The precision of LN-gen was confirmed at < 2.1% coefficient of variation, and the total error was calculated to be < or = 7.7% for both normotriglyceride and elevated triglyceride specimens at HDL-C decision points of 0.35 g/L and 0.60 g/L. CONCLUSIONS: The LN-gen HDL-C assay offers a cost-effective convenient method for meeting the 1998 precision, bias, and total error recommendations of the National Cholesterol Education Program.

Cytological and immunocytochemical analysis of laterocervical lymph nodes in patients with previous thyroid carcinoma.

BACKGROUND: In the follow-up of patients with a history of thyroid carcinoma, an enlarged cervical lymph node may indicate metastatasis is underway. Various methods may be utilized in the differential diagnosis between cancer metastasis of thyroid origin and aspecific lymphoadenitis. The aim of the present study was to evaluate the sensitivity and specificity of fine needle aspiration biopsy (FNAB) and the additional diagnostic value of immunocytochemical thyroglobulin staining on FNAB of neck nodes. METHODS: We evaluated cytologically 38 samples obtained by ultrasound-guided FNAB on laterocervical nodes from patients with a history of thyroid carcinoma. One smear for each case was selected for the immunocytochemical stain. RESULTS: Twenty-eight of those samples were adequate (16 positive for metastasis of thyroid origin and 12 negative) and 10 inadequate. Two of the cytologically positive samples from poorly differentiated neoplasia showed no reaction to thyroglobulin (Tg). In ten of the 11 cases classified as lymphoadenitis, no immunoreaction was present; in the last case, blastic-like cells showed a scanty cytoplasmic rim which was immunoreractive to Tg. Therefore, this case was reclassified as a metastatic tumor. CONCLUSIONS: Based on our results, we would recommend that FNAB be routinely performed in the diagnostic evaluation of neck masses. If the FNAB is inconclusive, aspiration should be repeated, while immunoperoxidase stain to evidence Tg, may be an adjunctive diagnostic tool in cytologically negative cases.

Immunohistochemical expression of p53, nm23-HI, Ki67 and DNA ploidy: correlation with lymph node status and other clinical pathologic parameters in breast cancer.

BACKGROUND: The different clinical evolution of breast cancer with similar pathological characteristics prompted the authors to investigate the prognostic significance of different biological markers. METHODS: Seventy-one primary breast carcinoma specimens obtained by mastectomy or quadrantectomy were examined for the determination of the p53, nm23 and Ki67 expression, with immunohistochemistry, and the DNA content, with static cytometry. RESULTS: p53 protein was expressed as nuclear staining in 58% of the cases and was associated with high levels of Ki67, non-diploid lesions and lymph-node status. Positive staining for nm23 was significantly correlated only with histologic grading. A predictive role in disease recurrence was demonstrated only in patients with a high Ki67 nuclear expression. CONCLUSIONS: From these data, we may conclude that, besides all the other traditional clinical morphological parameters, a panel of different biological markers, such as Ki67 and the determination of p53 expression, may be utilized to further characterize breast cancer and its biological behavior.

Fine needle aspiration biopsy in the preoperative management of patients with thyroid nodules.

The aim of this study was to evaluate the role of Fine Needle Aspiration Biopsy (FNAB) in the preoperative diagnostic management of patients with solitary or dominant thyroid nodules. This study was performed on 1054 patients followed for various thyroid disorders during a three year period (1992-1995). One hundred thirty eight patients were surgically treated, 61 after cytological indication and 77 after clinical indication, of these, 67 were cytologically negative and 10 were not conclusive. The cytological diagnosis was compared to the final histological result. Among the 138 cases, 27 were malignant, 39 were adenomas and 72 were benign lesions. Of the 67 cytologically negative cases, 63 (94%) were histologically benign, three were papillary carcinomas and one was an oxyphilic adenoma. Of the 45 cytologically suspicious aspirates, four were malignant neoplasias, 38 were follicular adenomas, two were hyperplastic goiters and one was an Hashimoto thyroiditis. All the 16 cytologically positive cases, were confirmed histologically. The limits of FNAB, which emerge from our and other studies, were based mainly in the difficulty of discriminating follicular adenomas from well differentiated follicular carcinomas. Nevertheless, FNAB with ultrasonographic support, has been unanimously accepted as a guide test in the selection of patients with thyroidal pathology who need surgery.

[Value of immunohistocytochemistry in the diagnosis of laterocervical masses in patients with a previous history of thyroid carcinoma]. / Valore della immunocitochimica nella diagnosi di masse laterocervicali in pazienti con pregresso carcinoma della tiroide.

BACKGROUND: The aim of this study is to evaluate the additional diagnostic significance of immunocytochemical staining of thyreoglobulin (TG) in Fine Needle Aspiration Biopsy (FNAB) of neck lymph-nodes, in patients with a previous history of thyroid carcinoma. METHODS: Twenty-five smears performed by ultrasound-guided FNAB on laterocervical nodes with a 21-23 gauge needle were evaluates. All smears were stained according to Papanicolaou and microscopically examined. RESULTS: Of these 25 smears, 15 were diagnostic and 10 were non diagnostic. Of the 15 diagnostic cases, 10 were positive for metastatic lesions from thyroid neoplasm and the other 4 were classified as reactive lymphoadenitis. One smear for each case was selected for the immunohistochemical stain. All the 10 non-diagnostic cases showed no reaction to thyreoglobulin. Neoplastic cells, from 9 out of 11 cytologically positive smears, expressed thyreoglobulin in the cytoplasm. In one case no reaction was evident and the other one was discarded for technical reasons. In 3 of the 4 cases cytologically classified as lymphoadenitis, immunoreactive thyreoglobulin was not found. In the fourth case, blastic-like cells showed a scanty cytoplasmic rime which was immunoreactive for TG and thus was classified as a metastatic tumour. On this basis, it is suggested that FNAB should be performed routinelly in the diagnostic evaluation of neck masses of unknown origin in patients with a previous history of thyroid neoplasm. CONCLUSIONS: If the FNAB is inconclusive, a second aspiration should be performed while immunoperoxidase stain to evidentiate TG may be an adjuntive diagnostic tool in cytologically negative cases.