Should fine‐needle aspiration cytology be the first choice diagnostic modality for assessment of all nonpalpable breast lesions? The experience of a breast cancer screening center in Alexandria,Egypt

Fine‐needle aspiration cytology (FNAC) of breast masses has been replaced by ultrasound‐guided core‐needle biopsy (USG‐CNB) in many countries. However, in Egypt, breast FNAC continues to play the major role in diagnosing breast masses. In this prospective study, we evaluated the efficacy of USG‐FNACs performed at a breast cancer screening center by comparing the FNAC results with the corresponding definitive histological examination outcome. We also investigated the role that CNB can play as a complementary diagnostic tool for FNAC in selected cases. A total of 229 consecutive nonpalpable breast masses were included in this study. Each FNAC was placed into one of four categories: 3.5% nondiagnostic, 13.5% benign, 12.3% atypical/suspicious (indeterminate), and 70.7% malignant. The overall diagnostic accuracy was 98.9%, with a specificity and sensitivity of 99.3 and 96.7%, respectively. The overall positive predictive values and negative predictive values were 99.3 and 96.7%, respectively. Only 37 masses (16%) were converted to CNB, with the indeterminate cytology being the most common cause (54%) for this conversion. Two cases demonstrating the superior benefit of FNAC over CNB are illustrated. Although we started the study by reserving CNB as a first choice to assess microcalcifications without architectural distortion, we ended the study by deciding to perform combined FNAC and CNB for this type of lesions. In conclusion, aiming to maximize the preoperative diagnosis of cancer, it would be cost efficient and time saving to use FNAC as a first‐line investigation to benefit from the wealth of cytological information yielded, followed by CNB in selected cases. Diagn. Cytopathol. 2010;38:880–889. © 2010 Wiley‐Liss, Inc.     

Fine needle aspiration cytology in two cases of chondromyxoid fibroma of bone and review of literature

We report the cytological features of two cases of chondromyxoid fibroma (CMF) confirmed by histopathology examination. First case was a 40‐year‐old male who presented with a foot swelling, and the second case was a 16‐year‐old male with a lesion at the angle of jaw. A fine needle aspiration cytology (FNAC) was performed in both the cases. In first case, a correct diagnosis of CMF could be offered on FNAC. In the second case, though the cytology diagnosis was a sarcoma considering the cytological, radiological and clinical features, the histopathological examination confirmed the same to be a CMF. The cases are being discussed to highlight the usefulness of FNAC to diagnose these uncommon benign bone lesions and the potential pitfalls in the cytological diagnosis of chondroid lesions. Diagn. Cytopathol. 2013;41:904–908. © 2012 Wiley Periodicals, Inc.     

Fine-needle aspiration cytology of primitive neuroectodermal tumor of the urinary bladder: a case report

Primitive neuroectodermal tumors (PNETs) are malignant small round cell tumors, which exhibit a variable degree of neural differentiation. These tumors are usually found in the extraosseous soft tissue and rarely in bones. Occasional cases of PNETs of the urinary bladder have been reported on histopathology. However, to the best of our knowledge, none have been diagnosed on fine-needle aspiration cytology (FNAC). A patient presented to the out-patient department with complaints of a slowly progressive lump in the lower abdomen, which was diagnosed as PNET on FNAC. The smears showed a dispersed population and sheets of malignant small round cells with focal rosette formation and perivascular arrangement of tumor cells. Periodic acid-Schiff staining showed strong cytoplasmic positivity. Immunocytochemistry of the cytology smears also showed strong membrane positivity for CD99 (MIC-2), which was also confirmed on histopathological examination. PNET of the urinary bladder is a distinct entity, which can be diagnosed on FNAC and confirmed by immunohistochemistry. A diagnosis of PNET should be considered as a differential diagnosis in urinary bladder masses, especially in adolescents and young adults.     

Carcinoid of the Ovary

Carcinoid of the ovary is an uncommon tumor. In the present article we have described the cytological features of carcinoid of the ovary in a 53‐year old post‐menopausal female. The patient presented with abdominal discomfort and loose stools. Ultrasound‐guided fine‐needle aspiration cytology (FNAC) of the left adnexal mass showed clusters and also scattered, relatively monomorphic population of tumor cells with vague rosette‐like structures. Cytological diagnosis of malignant ovarian tumor possibly sex cord stromal tumor or carcinoid of ovary was offered and subsequent histopathology and immunohistochemistry confirmed the diagnosis of carcinoid. Diagn. Cytopathol. 2014;42:612–614. © 2013 Wiley Periodicals, Inc.     

Fine-needle aspiration cytology combined with flow cytometry immunophenotyping is a rapid and accurate approach for the evaluation of suspicious superficial lymphoid lesions

The authors report a prospective study on 88 samples of superficial lesions (lymph nodes, skin nodules, and breast tumors), performed by fine-needle aspiration cytology (FNAC) in 74 patients, allowing (i) morphologic analysis combined with immunophenotyping by flow cytometry (FCM) and (ii) a cytogenetic study in 33 cases. Thirty-nine FNAC (44.3%) were performed at the time of diagnosis. The cytology results were correlated with histopathologic examination in 32 cases. Forty-nine FNAC (55.7%) were performed in the context of follow-up of a lymphoma and the results were correlated with those of histopathologic examination in 14 cases.In this study, the concordance between FNAC plus FCM and histopathologic examination was 90% for low-grade non-Hodgkin's malignant lymphomas (NHLs) and 83% for high-grade NHL. The limits of this morphologic and phenotypic approach are (i) partial tumor infiltrations, (ii) Hodgkin lymphoma, and (iii) T-cell NHL.In conclusion, it may be said that this combined approach is very useful for diagnosis and follow-up of patients but requires teams experienced in the sampling technique and the morphologic diagnosis of the various types of low-grade NHL in which supplementary ancillary studies may be performed when morphology and flow cytometry immunophenoyping are not conclusive.     

Fine‐needle aspiration biopsy of pleural metastases from a carcinosarcoma or true malignant mixed tumor of the parotid gland mimicking a mesothelioma

Malignant mixed tumor of the parotid is known to have odd sites for metastases. We describe the fine‐needle aspiration cytology (FNAC) findings of pleural metastasis from a malignant mixed tumor misdiagnosed as a mesothelioma on cytology at the onset. A 47‐year‐old man presented to us with breathlessness and a massive pleural effusion with pleural‐based nodules. He had been operated 2 years before for a pleomorphic adenoma of the parotid and had a healthy scar at that site. FNAC from the pleural lesions showed myxoid background substance with entrapped cuboidal epithelial cells with atypical nuclei, which were interpreted as mesothelial cells. These cells in contrast to the usual mesothelial cells were not arranged in sheets but rather were huddled in places and formed a pseudoacinar pattern and blended with the myxoid substance. After the diagnosis of a mesothelioma, patient received pemetrexed and cisplatin based chemotherapy with partial response. While on chemotherapy tumor recurred at the primary site in parotid and was confirmed to be a carcinosarcoma on a FNAC and biopsy. To conclude, pleural metastases from a true malignant mixed tumor of the parotid gland can be misdiagnosed as mesothelioma and could occur in the absence of uncontrolled disease at primary site. Both mesotheliomas and pleomorphic adenomas metastatic to the pleura are biphasic tumors, but in a patient with history of pleomorphic adenoma, the latter should be kept as a foremost possibility. Attention to the cytomorphology of tumor cells will also assist in confirming the diagnosis. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Non‐Hodgkin's lymphoma presenting as breast masses: A series of 10 cases diagnosed on FNAC

Primary breast lymphoma (PBL) is a rare disease, which comprises 0.04–0.53% of all primary malignant tumors of the breast. The most frequent histological subtype is diffuse large B‐cell type (DLBCL) (40–70%). Differentiation of PBLs from other breast tumors such as poorly differentiated carcinomas and lobular carcinoma may at times be difficult on cytomorphology alone. An audit of breast lymphomas diagnosed on fine needle aspiration cytology (FNAC) over a period of 9 years (2001–2009) was performed. Ten cases were retrieved and the cytomorphology was reviewed along with immunochemistry (IHC), flow cytometry as well as histopathology, wherever available. The age of patients ranged from 17 to 83 years. Eight cases were diagnosed as non‐Hodgkin's lymphoma, high‐grade on FNAC. Histopathology was available in four of these cases and cell block was available in one case. Lymphoid cells were positive for leukocyte‐common antigen (LCA) and CD20 and negative for CD3 in these cases. The same was confirmed by flow cytometry on aspirated material in one case. A diagnosis of DLBCL was offered in these five cases. One case was a low‐grade NHL and another case was a young male, a known case of acute leukemia and had leukemic infiltration in the breast lump. We wish to emphasize the potential importance of FNAC in breast lymphoma and the same can be helpful to avoid unnecessary surgery in these cases. The differential diagnostic entities have been discussed. IHC and flow cytometry can be performed on the aspirated material and provide valuable information. Diagn. Cytopathol. 2013. © 2011 Wiley Periodicals, Inc.     

Cytodiagnosis of benign fibrous histiocytoma of rib and diagnostic dilemma: A case report

Benign fibrous histiocytoma (BFH) of bone is rare in occurrence, and rib is an unusual site. There are limited case reports of this entity in the literature, and cytodiagnosis of this tumor is not described. A 24‐year‐old man presented with a firm mass and pain in the right lateral chest wall. Radiological investigations (plain radiograph and computed tomography) revealed a lytic bone lesion involving the 5th rib. Radiologically, giant cell tumor (GCT), BFH, and plasmacytoma were suspected. In fine‐needle aspiration cytology (FNAC), admixture of benign stromal cells and scattered osteoclast type giant cells were found in the smears. Differential diagnoses of BFH, GCT (non‐epiphyseal type), fibrous dysplasia, and aneurysmal bone cyst were made on cytology. Subsequent histologic examination confirmed the diagnosis of BFH. Cytologic diagnosis of BFH of rib is difficult as this tumor may mimic other giant cell containing tumors of bone in FNAC. The final diagnosis should always be made after correlation with histological, radiological, and clinical features. Diagn. Cytopathol. 2010. © 2009 Wiley‐Liss, Inc.     

Fine needle aspiration cytology (FNAC) of gastrointestinal stromal tumor: an emphasis on diagnostic role of FNAC,cell block,and immunohistochemistry

Recently the origin of gastrointestinal stromal tumors (GISTs) is thought be the interstitial cells of Cajal or primitive stem cells. This study was performed to evaluate the roles of fine needle aspiration cytology (FNAC), cell block preparation, and immunohistochemistry in the diagnosis of GISTs. Nine cases of GIST in which FNAC was performed were included in this study. Cytologically, the tumor cells characteristically occurred in closely packed cohesive tissue fragments with high cellular density often in bloody background. The tumor cells often formed fascicles with parallel, side-by-side arrangements of the nuclei. Histologically, GISTs were highly cellular spindle or epithelioid tumor with basophilic appearance. Immunohistochemically, GISTs were c-kit positive in all of nine cases, CD34 positive in seven, focally SMA positive in two, and S-100 and GFAP negative in all. Both histologic and cell block sections showed the same histologic and immunohistochemical features. Cytomorphologically GISTs show a broad morphologic spectrum but rarely a significant nuclear pleomorphism and the assessment of malignant potential is difficult based on cytology alone. However, in the appropriate clinical and radiologic setting, a confident diagnosis of primary or metastatic GIST can be established by FNAC, cell block, and immunohistochemistry.     

Diagnosis of pediatric neuroblastoma by urine cytology: A case report

Neuroblastomas are embryonal tumors arising from the neuronal crest cells of the synaptic nervous system. Findings from aspiration cytology have been reported, but there have been no reports of urine cytology findings. Here, we report a case of pediatric neuroblastoma characterized by urine cytology. A 2‐year‐old boy presented with abdominal pain, nausea, and loss of appetite. Computed tomography revealed a large tumor in the left suprarenal region with massive infiltration into the kidney. Urinary cytology showed highly cellular clusters composed of small, round, atypical cells with little cytoplasm and high nuclear/cytoplasmic ratio; nuclear molding was also noted in some places. Immunocytochemical staining was positive for synaptophysin and chromogranin A, and neuroblastoma was suggested by urine cytology. A biopsy of the left adrenal tumor later confirmed a diagnosis of poorly differentiated neuroblastoma. Urine cytology may be useful for rapid diagnosis and management of similar cases.     

Aspiration cytology of extramammary tumors metastatic to the breast.

This study was carried out to examine the cytomorphologic features of metastatic breast tumors and to assess the utility of fine-needle aspiration cytology (FNAC) in diagnosing these tumors. The study group comprised five females and one male, all presenting with a breast mass. Their ages ranged between 35 and 65 years. FNAC of the breast mass was done in all cases. Three of the cases were previously diagnosed as squamous cell carcinoma (SCC) of the cervix, mucinous cystadenocarcinoma (MCA) of the ovary, and melanoma. Three cases presented initially with a breast mass. These included melanoma, non-Hodgkin's lymphoma (NHL), and plasmacytoma. The diagnosis of NHL was confirmed on histology. The patient with plasmacytoma presented primarily with a breast lump but subsequently developed multiple myeloma, and in one case of melanoma the primary tumor was detected after breast metastases. Preoperative FNAC of extramammary tumors metastatic to the breast is invaluable because the management of the patient differs entirely from that of a primary neoplasm. An accurate diagnosis can be made with the help of clinical and radiological correlation. If available, a perusal of previous history and biopsy material may prove useful.     

Role of fine-needle aspiration cytology in the diagnosis of secondary tumors of the thyroid--twenty years' experience

Secondary tumors of the thyroid, presenting as thyroid nodules although rare, have been documented in literature. This study highlights the frequency, primary sites, and the role of fine-needle aspiration cytology (FNAC) in evaluating secondary tumors of the thyroid at a tertiary care hospital. There were 24 documented cases of secondary tumors of the thyroid from 1982 to 2002 (20 years). The aspirates and histology slides of all these cases were reviewed and the findings noted. On FNAC, 17 cases were diagnosed as secondary tumors, 3 as primary, and in 4 cases it was difficult to categorize the tumors as either primary or secondary. In 12 out of 24 cases, the primary tumor was seen to arise in the larynx (9), and in other sites anatomically close to the thyroid including the trachea (1), and the esophagus (2). Metastases from distant organs were also observed. Secondary tumors of the thyroid are rare and should be suspected in patients when the FNAC shows cytological features not seen in primary thyroid tumors. FNAC alone was required to accurately diagnose secondary tumors of the thyroid in a majority of cases (17/24); however, in some cases ancillary techniques may be required for a definite diagnosis.     

提高乳腺肿物针吸细胞学诊断正确率措施的探讨

目的探讨提高乳腺肿物针吸细胞学（ＦＮＡＣ）诊断正确率、降低误诊率、规范诊断报告形式及充分发挥其作用的措施。方法对１６２９例病人行ＦＮＡＣ检查，其中４４４例获病理组织学核对。结果３０７例恶性肿瘤诊断的敏感性和１３７例良性病变诊断的特异性分别为９５．８％和９８．５％，总正确率为９６．６％；假阴性率为４．２％，潜在假阳性率为１．５％，无１例假阳性，总误诊率为３．４％。结论我们认为（１）使用优良的穿刺器械及制片技术，实行“一体化”工作程序，认真进行细胞学与组织学对照，对提高乳腺肿物ＦＮＡＣ诊断正确率及降低误诊率具有重要意义。（２）Ｂｅｔｈｅｓｄａ乳腺ＦＮＡＢ统一方案中提出的诊断报告形式值得借鉴。（３）ＦＮＡＣ在乳腺肿物的诊治中能够发挥出更重要的作用。     

Fine-needle aspiration cytology diagnosis of metastatic nonhaematological neoplasms of the breast: a series of seven cases

Metastatic neoplasms of the breast are rare. Mammary metastases as the initial presentation are even more infrequent and can simulate a primary malignancy clinically and radiologically. Recognition of metastatic tumors in the breast is important because it would prevent unnecessary mutilating surgery and would lead to appropriate treatment of the primary tumor. There is a broad variety of cytological appearances reported about primary tumors and few reports about secondary breast malignancies, specially diagnosed by FNAC. This study was carried out to examine the clinical and cytomorphologic features of metastatic breast tumors found in 12 de Octubre University Hospital during a period of 20 years. It confirms the utility of FNAC and describes findings that can help in the differential diagnosis that sometimes can be very difficult. Seven cases of nonhematological metastatic neoplasms of the breast were identified from the files of the Department of Pathology of the 12 de Octubre University Hospital from a total of 64,000 aspirates. We included only metastatic tumors from extramammary nonhematological neoplasms. There were nine cases of hematological metastatic neoplasm that were excluded. They were diagnosed with FNAC and confirmed by histopathology, with at least three years of follow up. The breast lump was the first manifestation of malignancy in one case of synovial sarcoma. The other six cases had been previously diagnosed of cancer. These included one malignant melanoma, one alveolar rhabdomyosarcoma, one mixed müllerian tumor, one medullary carcinoma of thyroid, one colonic adenocarcinoma, and one gastric adenocarcinoma. The period of time between primary tumor and metastases ranged from one month to eight years. An accurate cytologic diagnosis was made in all the cases. Immunocytochemistry was available but diagnosis could be made with cytomorphology alone in the seven cases. Fine-needle aspiration cytology is an excellent first line diagnostic modality that is particularly informative when clinical previous data are known. If metastatic disease is suspected, the material obtained by FNAC may provide a definitive diagnosis and prevent open surgical biopsy or mastectomy. We concur with previous reports that FNAC is a reliable, rapid, secure, and cost-effective approach to the diagnosis of palpable metastatic breast tumors.     

Role of fine-needle aspiration cytology in the preoperative evaluation of smooth muscle tumors

A preliminary study was undertaken to assess the feasibility and the diagnostic role of fine-needle aspiration cytology (FNAC) in the preoperative evaluation of eight uterine smooth muscle tumors manifesting as single large masses with signs of growth. Percutaneous FNAC was performed under echographic control with a 22-gauge needle and the material was stained according to conventional techniques. Histology of surgically resected specimens was available for final diagnosis and comparative analysis in all the cases, including five leiomyomas (LM), one smooth muscle tumor of uncertain malignant potential (TUMP), and two low-grade leiomyosarcomas (LMS). Cellularity, as indicated by the density (crowding) of nuclei reflecting the amount of cytoplasmic volume, and the cohesiveness of the tissue fragments in the smears appeared to be the most important diagnostic parameters in the distinction between LM and LMS. LM usually showed few scattered poorly cellular fragments of highly cohesive tapering cells without nuclear crowding and with abundant cytoplasm. LMS usually showed a large number of single cells and fragments of loosely arranged tapering cells with nuclear enlargement and crowding and ill-defined scanty cytoplasm. Borderline forms such as TUMP were hardly distinguishable from LMS and LM. FNAC appears to be a feasible preoperative procedure in uterine smooth muscle tumors and may play a diagnostic role, especially in distinguishing frankly benign from overtly malignant forms. Diagn. Cytopathol. 16:326–330, 1997. © 1997 Wiley-Liss, Inc.     

Sensitivity and specificity of fine needle aspiration for the diagnosis of mediastinal lesions

Fine needle aspiration cytology (FNAC) of mediastinal masses allows for rapid on-site evaluation and the triaging of material for ancillary studies. However, surgical pathology is often considered to be the gold standard for diagnosis. This study examines the sensitivity and specificity of FNAC compared to a concurrent or subsequent surgical pathology specimen in 77 mediastinal lesions. The overall sensitivity for mediastinal mass FNAC was 78% and the overall specificity was 98%. For individual categories the sensitivity and specificity of FNAC was respectively as follows: inflammatory/infectious (33%, 99%), metastatic carcinoma (93%, 100%), lymphoma (84%, 97%), cysts (25%, 100%), soft tissue tumors (100%, 100%), paraganglioma (50%, 100%), germ cell tumor (100%, 99%), thymoma (87%, 94%), thymic carcinoma (60%, 100%), benign thymus (0%, 100%), and indeterminate (100%, 90%). For different locations within the mediastinum the sensitivity and specificity of FNAC was respectively as follows: anterosuperior mediastinum (80%, 98%), posterior mediastinum (33%, 95%), middle mediastinum (100%, 100%), and mediastinum, NOS (79%, 99%). Thus, mediastinal FNAC is fairly sensitive, very specific, and is a valuable technique in the diagnosis of mediastinal masses.     

Cutaneous and subcutaneous metastases from internal malignancies: an analysis of cases diagnosed by fine needle aspiration

Cutaneous and subcutaneous metastases from internal malignancies are rare and indicate a dismal outcome for the patient. This study is designed to analyze cases of cutaneous and subcutaneous metastases from a known or unknown primary and evaluate usefulness of fine needle aspiration cytology as a diagnostic modality. The present study is a retrospective analysis of 83 patients who were diagnosed with metastatic skin deposits on fine needle aspiration cytology. Seventy-four patients were previously diagnosed cases of malignancy and nine patients had metastatic deposits simultaneously with the primary tumor. The commonest malignancies showing cutaneous metastases were from breast, colon and rectum, lung, ovary, and thyroid. The differential diagnoses are from primary cutaneous tumors. FNAC provides a rapid diagnosis and should be used as a preferred first line diagnostic modality in such patients. In our study, FNAC yielded a sensitivity and specificity of 100% as a microscopic method for confirmation.     

Spectrum of orbital and ocular adnexal lesions: an analysis of 389 cases diagnosed by fine needle aspiration cytology

The aim of the present study was to evaluate the scope and the limitations of fine needle aspiration cytology (FNAC) in orbital and ocular adnexal lesions. This study was a retrospective audit of 389 cases of orbital and ocular adnexal lesions subjected to FNAC over a period of 12 years (1998-2009). The cyto-smears were reviewed and the lesions were categorized under different diagnostic categories in adult and pediatric population. Three hundred and one adult patients (age ≥15 years) and 88 pediatric patients (age ≤14 years) constituted the study group. In the adult population, there were 23.3% cases of infectious and lymphoproliferative lesions and 12.6% of benign cysts. In the pediatric population, 18.2% cases had infectious and lymphoproliferative lesions and 8% had benign cysts. Various benign tumors (9.6% in adults) included pleomorphic adenoma, meningioma, and schwannoma. Benign vascular tumors predominated in the pediatric population. A majority of malignant tumors in adults were lymphoreticular malignancies (12.6%); non-Hodgkin's lymphoma being the most common followed by malignant epithelial tumors (10.3%). Nearly 3.6% cases of soft tissue/bone sarcomas and 6.3% of metastatic tumors were seen in adult population. However, most of the orbital tumors in the pediatric population were malignant small blue round cell tumors (33%). FNAC is a cost-effective technique with good diagnostic value in the assessment of ophthalmic lesions, especially when sampling and interpretation are performed by experienced personnel in the light of clinico-radiological information.     

Metastases to the kidney: eleven cases diagnosed by aspiration biopsy with histological correlation

Metastases to the kidney from extrarenal primary tumors are uncommon and may mimic renal-cell carcinoma clinically when presenting as a single mass with hematuria. Fine-needle aspiration biopsy (FNAB) is a useful diagnostic method for the evaluation of primary renal tumors. Only a few studies have investigated the value of cytological evaluation of secondary renal tumors. We report our experience with these tumors. Eleven cases of extrarenal primary tumors metastatic to the kidney, diagnosed by aspiration biopsy with histological correlation, are discussed. The diagnosis of metastatic disease to the kidney was accurately made by aspiration biopsy. Knowledge of the patients' history, histological correlation with the primary tumor, and the radiological characteristics of the renal masses were helpful in achieving a correct diagnosis. FNA cytology (FNAC) is an accurate method for the diagnosis of tumors metastatic to the kidney. Distinction between primary and secondary tumors of the kidney is crucial to guide management and prevent unnecessary surgery.     

Tall cell variant of papillary thyroid carcinoma: Its characteristic features demonstrated by fine‐needle aspiration cytology and immunohistochemical study

Tall cell variant (TCV) of papillary thyroid carcinoma is a rare tumor, which is usually associated with poor outcome, and pathologists often face the dilemma of proper diagnosis of TCV, not only by cytology but also histology. To allow surgeons to determine aggressiveness of the tumor before operation, it is important for pathologists to detect tall cell features correctly by fine‐needle aspiration cytology (FNAC). However, the current criteria and definition of TCV are still controversial and confounded by another problem, the differential diagnosis from poorly differentiated thyroid carcinoma (PDC). In this report, we describe two cases of TCV and present characteristic FNAC findings. The tumor cells had a peculiar shape, which included tall, columnar, and oxyphilic cytoplasm with “eccentric,” basally located nuclei. We propose new terms for these cells, such as “tail‐like cells” or “tadpole cells.” In the surgically‐resected specimens, both cases exhibited remarkable extrathyroidal invasion accompanying prominent vascular invasions. They showed high Ki‐67 (MIB‐1) labeling index by immunohistochemistry, which indicated a higher proliferation activity of TCV than conventional form of papillary thyroid carcinoma. Furthermore, we discuss in this report the problematic issue of differential diagnosis of TCV from PDC and oxyphilic papillary thyroid carcinoma. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.