Nuclear crease as a cytodiagnostic feature of papillary thyroid carcinoma in fine-needle aspiration biopsies

A study to evaluate association of nuclear grooving in benign thyroid lesions with RET/PTC1 and RET/PTC3 gene translocation

INTRODUCTION

Papillary thyroid carcinoma (PTC) is the most common malignant lesion of the thyroid characterized by unique histological features like nuclear grooving, nuclear clearing, and intra-nuclear inclusions. However, nuclear grooves are observed even in benign thyroid lesions (BTL) like nodular goiter (NG), Hashimoto's thyroiditis (HT), and follicular adenoma (FA) resulting in diagnostic dilemma of the presence of PTC in such BTL. RET/PTC gene translocation is one of the most common oncogenic rearrangements seen in PTC, known to be associated with nuclear grooving. Among different types of RET/PTC translocations, RET/PTC1 and RET/PTC3 gene translocations are the most common types. These translocations have also been identified in many BTL like hyperplastic nodules and HT. Our study aimed to determine the frequency of nuclear grooving in BTL and evaluate their association with RET/PTC1 and RET/PTC3 gene translocation.

METHODS

Formalin-fixed, paraffin-embedded (FFPE) tissue blocks of NG, HT, and FA were included in the study. The hematoxylin and eosin (H&E) stained sections were evaluated for the presence of nuclear grooving/high power field (hpf) and a scoring of 0 to 3 was used for the number of grooves. Sections of 10 μ thickness were cut and the cells containing the nuclear grooves were picked using Laser-Capture microdissection. About 20 to 50 such cells were microdissected in each of the cases followed by RNA extraction, cDNA conversion, realtime-polymerase chain reaction (RQ-PCR) for RET/PTC1 and RET/PTC3 gene translocation, and the findings were analyzed for statistical significance.

RESULTS

Out of 87 BTL included in the study, 67 (77.0%) were NG, 12 (13.7%) were HT, and 8 (9.2%) were FA. Thirty-two cases (36.8%) had nuclear grooving with 18 out of 67 NG, 6 out of 12 HT, and all 8 cases of FA showing a varying number of nuclear grooves. A significant association between the number of nuclear grooves with RET/PTC gene translocation (p-value of 0.001) was obtained. A significant association of HT with RET/PTC gene translocation (p-value of 0.038) was observed. RET/PTC1 and RET/PTC3 translocation were seen in 5 out of 87 cases, with HT showing positivity in 2 and FA in 1 case for RET/PTC1 and HT in 1 and FA in 2 cases for RET/PTC3 gene translocation with 1 case of FA being positive for both RET/PTC1 and RET/PTC3 gene translocation.

CONCLUSIONS

The frequency of nuclear grooving among BTLs in our study was 36.8%. Our study shows, that when BTLs, show nuclear grooves, with an increase in the nuclear size, oval and elongated shape, favors the possibility of an underlying genetic aberration like RET/PTC gene translocation, which in turn supports the reporting pathologist to suggest a close follow up of the patients on seeing such nuclear features on cytology or histopathology sample, particularly in HT.

Value of Combined Cytomorphological Parameters in Improving Diagnostic Accuracy of Papillary Thyroid Carcinoma on Cytology - The Five Dependable Features

BACKGROUND

Fine-needle aspiration cytology remains the preliminary test for diagnosing papillary thyroid carcinoma (PTC). Numerous features are established to arrive at the diagnosis. However, few cases pose a challenge to correctly diagnose PTC. Our study aims to elicit the combination of features to aid in the diagnosis of such cases.

MATERIALS AND METHODS

Cytology smears of histologically proven cases of PTC and benign diagnoses were included as case (n = 36) and control group (n = 38), respectively. Features including papillae with cores, 3-D caps, nuclear grooves (NG), intranuclear cytoplasmic inclusions (INCI), giant cells, macrophages, cellular swirls, psammoma bodies, pale chromatin, nuclear overlapping, nuclear enlargement, and metaplastic cells were assessed. Statistic tests including Independent t test/Mann-Whitney Test and Chi-Square test/Fisher's Exact test were used. Receiver operating characteristic curve was used to assess the cut-off point of many cytological features to predict PTC. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of cytological features was calculated to predict PTC.

RESULTS

Presence of five or more cytological features (papillae with cores, cellular swirls, NG, INCI, and psammoma bodies) together could diagnose PTC (PPV) in 78.95% of the cases, with a NPV of 83.33%. Diagnostic accuracy of these five features combined was 81.08%. Papillae with cores and nuclear grooving were the most sensitive cytological features, whereas INCI followed by cellular swirls and NG were the most specific features.

CONCLUSION

Relying on a combination of the most sensitive and specific features rather than any one cytological feature can help reduce the misdiagnoses in PTC.

Cytological Evaluation of Thyroid Lesions by Nuclear Morphology and Nuclear Morphometry

Introduction:

Fine needle aspiration (FNA) of the thyroid gland is an effective diagnostic method. The Bethesda system for reporting thyroid cytopathology classifies them into six categories and gives implied risk for malignancy and management protocol in each category. Though the system gives specific criteria, diagnostic dilemma still exists. Using nuclear morphometry, we can quantify the number of parameters, such as those related to nuclear size and shape. The evaluation of nuclear morphometry is not well established in thyroid cytology.

Objective:

To classify thyroid lesions on fine needle aspiration cytology (FNAC) using Bethesda system and to evaluate the significance of nuclear parameters in improving the prediction of thyroid malignancy.

Materials and Methods:

In the present study, 120 FNAC cases of thyroid lesions with histological diagnosis were included. Computerized nuclear morphometry was done on 81 cases which had confirmed cytohistological correlation, using Aperio computer software. One hundred nuclei from each case were outlined and eight nuclear parameters were analyzed.

Results:

In the present study, thyroid lesions were common in female with M: F ratio of 1:5 and most commonly in 40–60 yrs. Under Bethesda system, 73 (60.83%) were category II; 14 (11.6%) were category III, 3 (2.5%) were category IV, 8 (6.6%) were category V, and 22 (18.3%) were category VI, which were malignant on histopathological correlation. Sensitivity, specificity, and diagnostic accuracy of Bethesda reporting system are 62.5, 84.38, and 74.16%, respectively. Minimal nuclear diameter, maximal nuclear diameter, nuclear perimeter, and nuclear area were higher in malignant group compared to nonneoplastic and benign group.

Conclusion:

The Bethesda system is a useful standardized system of reporting thyroid cytopathology. It gives implied risk of malignancy. Nuclear morphometry by computerized image analysis can be utilized as an additional diagnostic tool.

Autopsy Findings in Clinically Normal Thyroids

Thyroid glands obtained from 120 consecutive autopsies performed on patients who died from different causes, other than thyroid diseases, were systematically examined by light microscopy. There were 84 males and 36 females; their ages ranged from 1 day to 100 years. Histopathological findings were noted mainly in patients older than 48 years of age. In all cases thyroid lesions were incidental findings and included nodular goiter (26%), thyroiditis (9%), follicular adenomas (7%), papillary microcarci nomas (6%), follicular carcinoma (0.8%), and hemangioma (0.8%). A number of other morphologic changes of importance to surgical pathologists were also evaluated such as the presence of solid cell nests, intrathyroidal ectopic tissues, fibrosis, fat cell infiltration, and vascular changes. Int J Surg Pathol 1 (I): 25-32, 1993

Cytological, histological and ultrastructural nuclear features of monster cells in a canine carotid body carcinoma

A 7-year-old female Shih-tzu dog was presented with severe dyspnoea. A large mass was palpated in the left cranial neck. Cytological examination of an aspirate sample revealed cells with marked anisokaryosis, giant elements and many bare nuclei. Scattered intact giant cells showed scant, granular cytoplasm and intranuclear inclusions. Histologically, neoplastic cells were subdivided into lobules by fine collagenous trabeculae. Numerous pleomorphic giant, or 'monster', cells were observed, showing a highly indented nuclear envelope, intranuclear cytoplasmic pseudoinclusions (ICPs) and 'ground-glass' nuclear appearance. Neoplastic emboli were present, but no distant metastases were detected grossly. Immunohistochemically, the neoplastic cells expressed synaptophysin and had variable expression of neuron-specific enolase and vimentin. The cells were negative for pan-cytokeratin, CAM 5.2, glial fibrillary acidic protein and S100. Nuclear abnormalities and cytoplasmic neurosecretory granules were noted ultrastructurally. These features were consistent with a diagnosis of carotid body carcinoma (chemodectoma). Monster cells with ICPs have not been documented previously in canine chemodectoma.

Papillary thyroid carcinoma: an update

The past two decades have seen numerous developments in the understanding of the origins and biology of papillary thyroid carcinoma. Advances in molecular biology, clinicopathologic studies of new entities, facility with fine-needle aspiration biopsy, and new radiologic imaging techniques have allowed for earlier diagnosis of these tumors. However, these advances have also caused controversies in cytologic and histopathologic diagnoses as well as therapy decisions. This paper will focus on several pathologic aspects of papillary carcinoma, which impact on its biology and prognosis.

Pathogenesis and diagnostic significance of nuclear grooves in thyroid and other sites

Nuclear grooves are longitudinal invaginations of the nuclear envelope bilayer, which constitute a characteristic feature of papillary thyroid carcinoma. Their pathogenesis is not yet clear, but there is evidence for the involvement of a signaling pathway downstream of the protooncogene RET. The presence of nuclear grooves is not specific for papillary thyroid carcinoma because it has been documented in other types of thyroid neoplasms, in nonneoplastic thyroid lesions, in ovarian neoplasms (Brenner, adult granulosa cell, and transitional cell tumors), in breast carcinomas, in cervicovaginal and endometrial smears, in papillary neoplasms of several organs (such as papillary transitional cell carcinoma of the bladder, papillary renal cell carcinoma, papillary endometrioid carcinoma of the prostate), in thymic carcinomas, and in nonepithelial tumors.

Intranuclear cytoplasmic inclusions in fine-needle aspiration smears of papillary thyroid carcinoma: A study of its morphological forms, association with nuclear grooves, and mode of formation

Intranuclear cytoplasmic inclusion (INCI) and nuclear grooves in fine-needle aspiration (FNA) smears of papillary thyroid carcinoma (PTC) represent cytoplasmic invaginations into the nucleus. Although formation of INCIs is linked to nuclear grooves, they seldom exist together. This study was undertaken to find out the various morphological forms of INCIs, their relation to nuclear grooves, and mode of formation. FNA smears of 54 PTC cases were studied for various forms of INCI, nuclear chromatin pattern, nuclear grooves, and nuclear notches. A differential count of INCIs was made in 19 cases having > or =10 INCIs per 200 neoplastic cells. INCIs were present in 48 (88.9%) of 54 PTC cases. Round INCIs were present in 46 (85.2%) cases, followed by oval (48.1%), tear drop/flask-shaped (18.5%), irregular (14.8%), planoconvex/semicircular (13%), rectangular (9.3%), spindle-shaped (3.7%), and bilobed (3.7%). A differential count of INCIs also showed that the round form was the commonest (76.3%). The oval and other forms constituted 19.5 and 4.2%, respectively. INCIs and nuclear grooves were present together in a cell in 15 (27.8%) cases. The formation of INCIs as a cytoplasmic invagination into the nucleus was shown cytomorphologically in rare cells. For the first time in this study, the various morphological forms of INCIs, and the extent of their coexistence with nuclear grooves, (have been highlighted) and showed their mode of formation shown at a light microscopic level.

Psammoma body and its precursors in papillary thyroid carcinoma: A study by fine-needle aspiration cytology

Psammoma bodies (PBs) form an important diagnostic criterion of papillary thyroid carcinoma (PTC), but their mechanism of formation is not clear. Following our observation in a case of PTC that laminated hyaline globules may be the precursor form of PBs, the present study was undertaken to find out their relation to PBs in PTC cases. Fifty-four cases of PTC and 14 follicular neoplasms, diagnosed by fine-needle aspiration (FNA) cytology, were studied by one of the investigators (DKD) to find out the PBs, irregular calcifications, hyaline globules, and other forms made of similar material. PBs along with irregular calcification were present in five PTC cases, PB alone was present in 1 case, and irregular calcification alone was present in 4 cases. Large hyaline globules (LHGs), small hyaline globules (SHGs), branching hyaline cylinders (BHCs), and irregular hyaline deposits (IHDs) were identified in 10, 14, 6, and 9 cases, respectively. One or more of these four forms were present altogether in 18 (33.3%) of PTC cases and none of the follicular neoplasms (P=0.0142). These forms were present in 80.0% of cases with PB/irregular calcifications as opposed to 22.7% in cases without them (P=0.0012). Our observations suggest that LHGs, SHGs, and BHCs are precursors of PBs and IHDs serve as a nidus for irregular calcification.

Histiocytic aggregates in benign nodular goiters mimicking cytologic features of papillary thyroid carcinoma (PTC)

Macrophages/histiocytes are commonly seen in fine-needle aspiration biopsy (FNAB) specimens of thyroid nodules with varying degrees of cystic change. In some cases the histiocytic component of a cystic thyroid nodule can occur as large tissue fragments with marked nuclear atypia, including elongated nuclei with chromatin clearing, nuclear grooves, and membrane thickening. These nuclear changes mimic cytologic features of papillary thyroid carcinoma (PTC), thus leading to diagnostic difficulty in interpretation of FNAB specimens of benign cystic thyroid nodules. We evaluated ethanol-fixed Papanicolaou-stained smears of 273 cases of FNAB thyroid specimens from goitrous nodules with cystic change. Twenty cases were selected due to the presence of large aggregates of histiocytic cells with the above-mentioned nuclear atypia. An immunostain for histiocytic cells using CD68 was performed on alcohol-fixed slides. Histiocytic cells in tissue fragments with nuclear atypia mimicking PTC nuclei showed strong cytoplasmic staining for CD68; thyroid follicular cells stained negative for CD68. We conclude that histiocytic cells in cystic goitrous nodules can show nuclear features, which appear similar to PTC nuclei. Immunostaining for CD68 may be of value in differentiating between benign cystic thyroid nodules with histiocytic aggregates that mimic cytologic features of papillary carcinoma, and PTC with cystic change.

"Histiocytoid" cells in fine-needle aspirations of papillary carcinoma of the thyroid: frequency and significance of an under-recognized cytologic pattern

BACKGROUND

Although the classic cytologic features of papillary carcinoma of the thyroid in fine-needle aspirates have been well described, one uncommon feature, a vacuolated, histocyte-like cell without classic nuclear changes of papillary carcinoma, has been less well characterized.

METHODS

The author reviewed a large series of thyroid aspirates for specimens with these cytologic features.

RESULTS

Seven specimens were identified, representing approximately 6% of all aspirates with the features of papillary carcinoma and less than 0.5% of all aspirates. The cells resembled histiocytes but were larger, more atypical, and keratin positive in the one specimen that was tested. The cells had enlarged nuclei with abundant cytoplasm that often was vacuolated. The nuclei had grainy chromatin, occasional nucleoli, and lacked grooves and prominent pseudoinclusions. The background showed numerous, hemosiderin-laden macrophages typical of cyst contents in only three specimens. Calcifications were present in six specimens and resembled psammoma bodies in two specimens. Three specimens showed papillary carcinoma at resection, two specimens had other passes from the same nodule that were diagnostic of papillary carcinoma, and two specimens were from recent patients without follow-up. Only one of the three resected tumors showed prominent cystic change. None of 50 aspirates that were diagnosed as benign cyst contents had similar atypical cells, nor did resections of six predominantly cystic, benign lesions.

CONCLUSIONS

Histiocytoid cells are present in as many as 6% of all aspirates in which some features of papillary carcinoma are present. Increased awareness of these cells may help improve the sensitivity of fine-needle aspiration for the diagnosis of papillary carcinoma of the thyroid.

Focal features of papillary carcinoma of the thyroid in fine-needle aspiration material are strongly associated with papillary carcinoma at resection

The cytologic features of papillary carcinoma of the thyroid in fine-needle aspiration material have been well described. The significance of finding these features in only a small population of cells is not well characterized. I reviewed the results of 28 thyroid fine-needle aspirates processed as direct smears and cell blocks in which only a small population (<20 cells) showed features of papillary carcinoma. Papillary carcinoma was considered in 142 (8.98%) of 1,581 aspirates, and in 28 cases (1.77%), 20 cells or fewer showed features of papillary carcinoma and follow-up was available. Papillary carcinomas greater than 1 cm were identified in 11 cases (39%; 3 follicular variants), papillary carcinomas less than 1 cm were identified in 4 cases (14%), and benign lesions in the remaining 13 cases (46%). The background material (either scant or abundant benign epithelium) did not correlate significantly with the result of resection. Identifying features of papillary carcinoma in a small population of cells in either a scant or an abundant thyroid aspirate are associated with a high rate of papillary carcinomas at resection, only a minority of which represent either the follicular variant or incidental tumors.

Presence of nuclear grooves in endometrial cytology

Although the presence of nuclear grooving in papillary carcinomas of the thyroid has been well-described, so far the attention paid to similar structures in endometrial cell samples has been limited. In order to investigate the occurrence of nuclear grooves in endometrial specimens from patients with various pathologic conditions of the endometrium, we compared their appearance with papillary thyroid cancers. A total of 10 cases was studied (age range, 40-72 yr), all cases demonstrating nuclear grooves. In each case, 10 random high-power fields (HPFs) were investigated, and the numbers of fields in which nuclear grooving could be seen were recorded. Nuclear grooves were observed in 3-36 of each HPFs and were more often observed in atypical endometrial cells than in their normal-appearing counterparts; however, these nuclear alterations were thought to be nonspecific findings.

Nuclear grooves in fine-needle aspiration biopsies of breast lesions: do they have any significance?

Nuclear grooving is a recognized morphologic feature frequently seen in papillary carcinoma of the thyroid. This feature is also occasionally seen in other nonneoplastic and neoplastic conditions. Nuclear grooves have been described in tubular carcinoma of the breast. However, the significance of nuclear grooves in benign and malignant conditions of the breast has been rarely studied. In a retrospective study, we searched for the presence of nuclear grooves in Papanicolaou-stained and Diff-Quik-stained fine-needle aspiration biopsies (FNAB) of 50 cases of primary breast carcinomas, 25 cases of proliferative breast disease, and 25 cases of fibroadenoma. In addition, 10 cases of metastatic breast carcinoma diagnosed by FNAB were reviewed. Nuclear grooves were identified in 39 of 50 (78%) of the histologically confirmed primary breast carcinomas and in 9 of 10 (90%) of the cases of metastatic breast carcinomas in the Papanicolaou-stained smears. Nineteen of 50 (38%) of the cases of proliferative breast disease/fibroadenoma showed nuclear grooves in the Papanicolaou-stained smears. The difference between the percentage of cases showing nuclear grooves seen in the Papanicolaou-stained primary breast carcinomas and metastatic breast carcinomas compared with the benign breast lesions was statistically significant (P < 0.001 in the primary breast carcinoma cases and P < 0.01 in the metastatic breast cancer cases). Nuclear grooves were identified less often in the Diff-Quik-stained smears, and their presence in malignant lesions versus cases diagnosed as benign breast disease was not statistically significant. This study suggests that although the presence of nuclear grooves is more frequently seen in malignant breast lesions, their presence cannot totally exclude the possibility of benign breast disease. The presence of nuclear grooves, however, may serve as a diagnostic clue in metastatic tumors of unknown primary.

CD44 immunostaining of thyroid fine-needle aspirates differentiates thyroid papillary carcinoma from other lesions with nuclear grooves and inclusions

BACKGROUND

Although nuclear grooves and inclusions are considered to be characteristic cytologic features of thyroid papillary carcinoma, a variety of other thyroid lesions may on occasion display these features in fine-needle aspiration specimens.

METHODS

The authors evaluated the immunocytochemical staining of 16 fine-needle aspirations of thyroid papillary carcinoma and 14 aspirations of thyroid lesions confirmed to be other than papillary carcinoma but that included cells with nuclear grooving and/or inclusions, comprised of multinodular goiter (four cases), follicular adenoma (two cases), Hurthle cell adenoma (two cases), pure thyroiditis (three cases), and thyroiditis with nodular hyperplasia (three cases). CD44 previously has been shown to be selectively expressed in thyroid papillary carcinoma.

RESULTS

Of 16 surgically confirmed cases of thyroid papillary carcinoma featuring nuclear grooves and inclusions on fine-needle aspiration, 14 (88%) stained intensely for CD44 in a membranous pattern. Of the 14 nonpapillary thyroid carcinoma cases, only 1 (7%), a Hürthle cell adenoma, featured membranous CD44 staining. The difference in the proportion of cases with CD44 staining between the two groups was statistically significant (chi-square test, P < 0.001).

CONCLUSIONS

The authors conclude that immunostaining for CD44 can readily be performed on thyroid fine-needle aspiration specimens and that, for specimens featuring nuclear grooves and inclusions, the presence or absence of staining for CD44 may be of value in the distinction between thyroid papillary carcinoma and other lesions that may share some of the cytologic features of papillary carcinoma.

Intraepithelial Neutrophils in Thyroid Fine-Needle Aspiration: A Portent of Aggressive Thyroid Cancer?

We report three patients with papillary thyroid carcinoma in whom fine-needle aspiration (FNA) showed neutrophils within tumor cells. All three patients presented with large neck masses; at excision, two proved to be tall cell variants of papillary cancer. Nodal metastasis, extrathyroidal extension, and vascular invasion were found in both cases. One patient has experienced recurrent disease; the other has an increasing thyroglobulin titer but no clinically appreciable recurrence. The third patient refused further therapy, but brain metastases were noted clinically; this patient died of disease. In each case, FNA showed tumor clusters with characteristic nuclear features, papillary groups, and psammoma bodies. Neutrophils were present in the cytoplasm of tumor cells in the absence of necrosis. Immunostaining for proliferating cell nuclear antigen (PCNA), MIB-1 (Ki-67), and p53 tumor suppressor gene product was markedly positive. lntraepithelial neutrophils have not been previously reported in differentiated thyroid tumors. We postulate that these neoplasms produce specific leukocyte-attracting cytokines analogous to those produced by anaplastic and poorly differentiated thyroid carcinomas. We believe the finding of intraepithelial leukocytes in the absence of necrosis in thyroid FNA specimens represents a characteristic of clinically aggressive differentiated papillary neoplasms; in our small series, each represented a tall cell variant of papillary carcinoma.

The demise of follicular carcinoma of the thyroid gland

Over the past several decades, iodide supplementation to food supplies in many parts of the world has been followed by a corresponding decrease in the incidence of follicular thyroid carcinoma. However, pathologists continue to over-diagnose this tumor. Benign lesions (e.g., partly encapsulated hyperplastic nodules, pseudoinvasion after fine needle aspiration), and malignancies (especially the follicular variant of papillary carcinoma) have been misinterpreted as follicular carcinoma. Since the clinical features and biological behavior of true follicular cancer differ from the entities with which it may be confused, it is essential that appropriate histological criteria be applied to the diagnostic interpretation of thyroid nodules that exhibit follicular architecture. Only in this way will it be possible to define prognosis and to evaluate treatment options.

Nodular goiter: a histo-cytological study with some emphasis on pitfalls of fine-needle aspiration cytology

A comprehensive comparative histo-cytological study of 48 nodular goiters from an endemic goiter region was undertaken. Practically all features observed on the biopsies were identified, although with less frequency, on the smears. In agreement with previous observations, characteristic components of nodular goiter (NG) in aspirates included small to medium size epithelial cells with regular round nuclei, honeycomb pattern, large follicles, papillae showing the previously mentioned epithelial features, oxyphilic cells, and moderate to abundant background colloid material and thyroid phagocytes (macrophages). All eight features occurred together in only 2% of the studied cases, seven in 6 (12.5%), six in 4 (8%), five in 6 (12.5%), four in 12 (25%), three in 6 (12.5%), two in 11 (23%), and one in 2 (4%) cases, respectively. Regardless of the number and combination of features present, specific identification of NG on the smears may not always be possible and diagnostic pitfalls include thyroid cyst, Hashimoto's thyroiditis, granulomatous lesions, and, more frequently, follicular neoplasia. Our findings suggest that thyroid aspirates should be analysed with critical clinico-pathological approach and surgery considered only for nodules that are clinically suspicious or unresponsive to hormonotherapy when a diagnosis of follicular neoplasia is made.

Fine-needle aspiration biopsy of papillary thyroid carcinoma: cytologic, histologic, and ultrastructural correlations

Aspiration smears from a series of 21 papillary thyroid carcinomas were studied and a number of morphologic features correlated with the histologic and ultrastructural patterns. These included types of papillary structures, metaplastic cells, grooved and lobulated nuclei, optically clear nuclei, intranuclear inclusions, and macrophages. Generally there was a close correlation between histologic and cytologic findings. The numbers of macrophages and metaplastic cells appeared to be exaggerated in aspiration smears as compared with those seen on histologic sections. Optically clear nuclei were not seen on the air-dried cytologic smears. Grooved nuclei were somewhat difficult to recognize in the aspiration smears, although lobulated nuclei were identified easily. We consider the latter to be a significant feature in the diagnosis of papillary carcinoma. Ultrastructurally grooved nuclei showed a deep linear indentation of the nuclear membranes. Lobulated nuclei were characterized by multiple indentations that divided the nucleus into several lobules.

Medullary carcinoma of thyroid: a re-evaluation of the cytological criteria of diagnosis

We have reviewed the fine needle aspiration cytology appearances of a series of 31 consecutive and histologically confirmed medullary carcinomas of the thyroid. Despite the absence of a totally specific diagnostic feature, this retrospective re-evaluation indicates that a preoperative diagnosis of medullary carcinoma of the thyroid is possible in almost every case. The features occurring most commonly include a dispersed cell pattern in which round or spindle shaped cells with eccentric speckled nuclei were seen showing slight pleomorphism with inconspicuous nucleoli. In a third of cases fine red granularity was present in the cytoplasm in slides stained with Giemsa and by the Papanicolaou technique.

The significance of nuclear grooves and phagocytosis in the diagnosis of metastatic papillary carcinoma of the thyroid

A 57-year-old patient presented with a lesion of the iliac bone. Cytological smears prepared from material aspirated from the lesion revealed cells with longitudinal nuclear grooves and haemosiderin within their cytoplasm. These observations led to a diagnosis of metastatic thyroid papillary carcinoma which was confirmed by histological examination.

Fine-needle aspiration cytology of papillary Hürthle-cell tumors of thyroid: a report of three cases

Papillary Hürthle-cell tumors of the thyroid are composed of oxyphilic cells with a prominent papillary component. Their biologic behavior appears to be comparable with that of conventional papillary thyroid carcinomas. The literature on the fine-needle aspiration cytology of these tumors is scanty. The cytologic findings of three such cases are reported here. The findings suggest that most papillary Hürthle-cell tumors cannot be differentiated from other types of Hürthle-cell tumors cytologically.

Nuclear grooves: a useful criterion in the cytopathologic diagnosis of papillary thyroid carcinoma

A recent report emphasized the usefulness of the grooved nucleus as a diagnostic criterion of papillary thyroid carcinoma (PTC) in histopathologic material. The present study was undertaken to evaluate whether grooved nuclei can serve as an additional diagnostic criterion for PTC in cytologic material obtained by fine-needle aspiration (FNA). Slides from 124 consecutive thyroid FNAs were reviewed. Specimens included 11 PTCs, one follicular carcinoma, six follicular adenomas, eight follicular neoplasms not otherwise specified, 10 cases of chronic thyroiditis, and 88 colloid nodules/adenomatous goiters. Among the PTC cases, grooved nuclei were found in all 11 (100%), intranuclear inclusions in nine (82%), papillary fragments in seven (64%), and psammoma bodies in two (18%). Nuclear grooves were also observed in two of the 113 non-PTC cases (1.8%), both of which were colloid nodules, one with extensive Hurthle-cell change. The grooved nuclei were best identified on Papanicolaou-stained material. They were inconspicuous and difficult to identify in air-dried Diff-Quik-stained material. It appears that the recognition of grooved nuclei among tumor cells is a valuable diagnostic feature of PTC in cytologic material stained with polychromatic Papanicolaou stain.