Cytologic features of cribriform-morular variant of papillary carcinoma of the thyroid: a case report

BACKGROUND: While the histology of cribriform-morular variant of papillary thyroid carcinoma has been well documented, its appearance on cytologic smears has rarely been described given the rarity of this tumor. CASE: A 28-year-old woman had a neck lump for an unspecified duration for which she sought medical attention. She was previously well, and there was no significant family history of illness. Fine needle aspiration of the thyroid mass disclosed columnar cells with fine to granular chromatin and nucleargrooves associated with papillary fragments and acinar formation. Occasional groups of epithelial cells forming morules, previously unreported on cytology, were present. An excision specimen of the left thyroid nodule revealed morphologic features of cribriform-morular variant of papillary carcinoma of the thyroid. CONCLUSION: A diagnosis of cribriform-morular variant of papillary carcinoma of the thyroid could be established on fine needle aspiration cytology, prompting exclusion of familial adenomatous polyposis and distinguishing it from other, more aggressive variants of thyroid carcinoma, such as columnar cell carcinoma.     

Papillary Hyperplastic Nodule: Pitfall in the Cytopathologic Diagnosis of Papillary Thyroid Carcinoma

ObjectiveTo identify the pitfalls of overdiagnosing papillary formation as papillary thyroid carcinoma (PTC) in thyroid cytology specimens.MethodsPatients with papillary hyperplastic nodules who had preoperative fine-needle aspiration biopsy (FNAB) were selected for this study. All patients had been diagnosed as having either PTC or lesions suggestive of PTC on preoperative FNAB. Pathology reports, surgical reports, and cytopathology slides were reviewed and analyzed for demographic data, nature of surgery, and pathologic features.ResultsSix women and 2 men with a mean age of 49 years (range, 16-79 years) were included. The lesion size ranged from 1.0 to 3.5 cm. Four patients were diagnosed as having PTC and 4 as having lesions suspicious for PTC. FNAB specimens were available for review in 6 cases. Surgical pathology slides were reviewed in all cases. When cytologic material was evaluated for the morphologic features that led to the misdiagnosis of PTC by comparing it with FNAB specimens of classic variant of PTC, the specimens from these patients showed follicular cells arranged in short, nonbranching papillae in a background of watery colloid and macrophages. The follicular cells were round and demonstrated oncocytic change with nuclear enlargement, prominent central nucleoli, nuclear chromatin clearing, and intranuclear grooves.ConclusionsCaution should be exercised rendering the diagnosis of PTC on FNAB samples when a thyroid lesion shows papillary configurations and oncocytic cells and if convincing nuclear features of PTC are not present. Furthermore, some morphologic features on thyroid aspiration can help differentiate these cases from true PTC. (Endocr Pract. 2008;14:863-868)     

Atypical epithelial cells, cannot exclude papillary carcinoma, in fine needle aspiration of the thyroid

OBJECTIVE: Atypical epithelial cells, cannot exclude papillary thyroid carcinoma (AEC-PTC), in fine needle aspiration (FNA) of the thyroid is a controversial diagnostic category that might cause a dilemma in patient management. STUDY DESIGN: Eighty-eight thyroid FNA specimens from 86 patients with a diagnosis of AEC-PTC were retrieved from our files in a 10-year period from December 1996 to December 2006. Of the 86 patients, 57 had follow-up histologic diagnoses and were included in this study. The cytologic and histologic materials were reviewed and correlated. RESULTS: Of the 57 patients, all had cytologic atypical features suggestive of PTC. Twenty-five cases of PTC were identified at surgery (44%). Review of the cytologic materials identified the following cytologic features, either alone or in combination strongly associated with PTC at resection: rare intranuclear cytoplasmic invagination (INCI), squamoid cytoplasm and psammoma bodies. CONCLUSION: The most common reasons for rendering the diagnosis of AEC-PTC in FNA of thyroid include rare atypical cells in a cystic thyroid nodule or a background of Hashimoto's thyroiditis. The cytologic features of LNCI, squamoid cytoplasm and psammoma bodies should alert the pathologist. Focal cytologic features of PTC in FNA samples are strongly associated with papillary carcinoma on resection.     

Cytologic features of metastatic papillary thyroid carcinoma in cervical lymph nodes

OBJECTIVE: To elucidate the cytologic characteristics of metastatic papillary thyroid carcinoma (PTC) in cervical lymph nodes and the differences in cervical lymph nodes from those of stage I (intrathyroidal) PTC. STUDY DESIGN: Forty-seven cases of papillary thyroid carcinoma with cervical lymph node metastasis (group A) and 38 cases of intrathyroidal papillary carcinoma (group B) were included in this study. Preoperative fine needle aspiration cytology (FNAC) examination was performed on enlarged cervical lymph nodes (47 cases, group A) and enlarged thyroid nodules (13 cases, group A, and 38 cases, group B). All the cases were surgically excised and pathologically verified. The cytologic smears were reviewed and analyzed. RESULTS: The cytologic characteristics of metastatic PTC in cervical lymph nodes displayed a higher frequency of foamy macrophages (51.1% vs. 26.3%) and a lower frequency of distinct cell borders (38.3% vs. 71.1%) than those of stage I PTC. Metastatic PTC in cervical lymph nodes also had a higher frequency of cystic degeneration (44.7% vs. 5.3%) than intrathyroidal lesions. In 1 of the 47 cases with lymph node metastasis, the aspirate contained macrophages but no tumor cells. CONCLUSION: FNAC was useful in the diagnosis of metastatic PTC in cervical lymph nodes. However, because cystic degeneration appeared frequently, FNAC combined with thyroid ultrasonography to find the primary lesion is necessary in this situation.     

Morphologic spectrum of papillary carcinoma of the thyroid: role of cytology in identifying the variants

OBJECTIVE: To evaluate the efficacy of fine needle aspiration cytology (FNAC) in the diagnosis of morphologic variants of papillary carcinoma of the thyroid (PCT) and to determine the reasons for misdiagnosis in discrepant cases on cytology. STUDY DESIGN: Fine needle aspiration smears from 158 histologically proven cases of PCT were blindly reviewed and an attempt made to subclassify them into different variants on the basis of various architectural and morphologic features. Cytohistologic correlation was performed to assess the efficacy of cytology in correctly identifying these variants. RESULTS: In cases with satisfactory aspirates, the diagnosis of papillary carcinoma was correctly made in 112 of 139 (80.5%) histologically proven cases of PCT. Subclassification was correct in 87 of 96 (90.6%) cases of classic papillary carcinoma and in 25 of 43 (58.1%) of the other variants of PCT with adequate aspirates. Cytohistologic agreement was 100% in columnar cell variant (CCV) and high grade variant (HGV). Although there was overlap in the morphologic features of tall cell variant (TCV) and Hürthle cell variant, cytology correctly identified 60% and 76.4% of these cases, respectively. The accuracy of cytology was limited in diagnosing follicular variant as only 50% of these cases could be correctly typed on cytology. Nodular fascitis-like stroma and diffuse sclerosis variants could not be diagnosed on cytology. CONCLUSION: Though FNAC is of limited value in typing the variants of PCT due to overlapping morphologic features, it can provide clues to the diagnosis in certain aggressive variants such as TCV, CCV and HGV. Early diagnosis in these cases can assist clinicians with management.     

Papillary thyroid carcinoma and its variants in fine needle aspiration smears. A cytomorphologic study with special reference to tall cell variant

OBJECTIVE: To study the fine needle aspiration (FNA) cytologic features of papillary thyroid carcinoma (PTC) with special reference to its tall cell variant (TCV), which is the most aggressive of the variants. STUDY DESIGN: Fifty-four PTC cases were classified into variants, and the frequency of well-known morphologic criteria was determined. Four parameters were quantitatively analyzed based on a study of 200 consecutive neoplastic follicular cells: shape of cells, color of cytoplasm, intranuclear cytoplasmic inclusion (INCI) and nuclear grooves. RESULTS: The PTC cases included 6 TCV (> or = 30% tall cells), 8 cases with a significant tall cell component (sig. TCC) having 10-29% tall cells, 17 usual variant (UV), 17 follicular variant (FV) and 6 miscellaneous variants. TCV differed significantly from UV and FV in having a higher tall cell count, higher count of cells with reddish cytoplasm and INCI, and higher frequency of cases with lymphocytic infiltration. PTC (with significant tall cell component [TCC]) differed significantly from TCV with regard to tall cell count and lymphocytic infiltration, from UV with respect to tall cell count and monolayered sheets, and from FV with respect to tall cells, INCI, grooved nuclei, acinar formation, fire-flare appearance and giant cells. CONCLUSION: TCV was cytologically distinct from other variants. The biologic behavior of PTC cases with significant TCC, which morphologically seem to be a group intermediate between TCV on the one hand and UV and FV on the other, however, needs to be carefully monitored.     

Follicular variant of papillary thyroid carcinoma: diagnostic limitations of fine needle aspiration cytology

OBJECTIVE: To study the diagnostic sensitivity and specificity of fine needle aspiration cytology (FNAC) offollicular variant of papillary thyroid carcinoma (FVPTC). STUDY DESIGN: The study group consisted of 390 papillary thyroid carcinoma (PTC) cases diagnosed histologically with thyroidectomy specimens. The FNAC and histopathologic classification were compared in terms of the appearance of FVPTC and non-FVPTC statistically with the chi squared test. Also, several features of the cytologic smears of FVPTC were reviewed. RESULTS: Twelve of the 390 PTC cases were classified as FVPTC histologically. Five of the 12 cases were also reported as FVPTC in the diagnosis by FNAC and the other 7 as the usual type of PTC (UTPTC). There was 1 case classified as UVPTC histologically but FVPTC cytologically. If we use histologic diagnosis as the gold standard, the sensitivity and specificity of FNAC diagnosis of FVPTC were 42% and 83%, respectively. CONCLUSION: FNAC may be a good tool for diagnosing PTC, but it is unreliable to differentiate between FVPTC and UTPTC.     

Papillary carcinoma of the thyroid occurring during pregnancy. Report of a case diagnosed by fine needle aspiration cytology

A case of papillary carcinoma of the thyroid gland occurring during pregnancy in a 29-year-old woman is described. The enlarged thyroid nodule was first detected at 10 weeks of gestation; fine needle aspiration (FNA) of the nodule showed no cytologic evidence of malignancy. Repeat FNA at 30 weeks of gestation produced inadequate material for diagnosis. A final FNA at 38 weeks of gestation showed classic cytologic features of papillary carcinoma, including papillary structures, grooved nuclei and intranuclear cytoplasmic inclusions. After delivery, the patient was treated with total thyroidectomy and cervical lymph node dissection. The enlargement of the nodule in this case during the course of the pregnancy suggests a relationship between pregnancy and the malignant development of thyroid nodules; this is discussed along with the utility of FNA cytology for diagnosing thyroid cancers during pregnancy.     

Thin-layer cytology findings of papillary adenosquamous carcinoma of the cervix. Report of a case with histologic correlation and molecular analysis

BACKGROUND: Papillary squamotransitional cell carcinoma of the lower female genital tract is a rare form of malignancy with distinctive histologic features. To my knowledge, its adenosquamous counterpart has not been reported before. CASE: A 69-year-old woman presented with postmenopausal bleeding due to a bulky cervical tumor. The thin-layer cytology preparation (Autocyte, TriPath Imaging, Burlington, North Carolina, U.S.A.) was of high cellularity and contained multiple small, papillary clusters of basaloid to columnar cells. Discernible fibrovascular cores were noted. In the background were many loosely dispersed, bland-looking columnar cells as well as cells of high grade squamous intraepithelial lesion (CIN 3). On a diligent search, scattered adenocarcinoma cells containing distinct intracytoplasmic vacuoles were found. There were a small number of dyskaryotic squamous cells with bizarre shapes, assuming "tadpolelike" morphology. Histologic examination of the tumor biopsy showed a papillary tumor with central fibrovascular cores covered with mitotically active, poorly differentiated squamous cells that imperceptibly merged with abortive glandular structures. Molecular analysis using the polymerase chain reaction and restriction fragment length polymorphism revealed the presence of human papillomavirus type 16 DNA in the liquid-based cytology sample. CONCLUSION: Papillary adenosquamous carcinoma of the cervix shares some morphologic and even histogenetic overlaps with papillary squamotransitional cell carcinoma and, to a lesser extent, conventional endocervical adenocarcinoma. It may pose certain diagnostic dilemmas for the unwary. In view of its distinctive cytohistologic features, this tumor warrants greater recognition in gynecologic pathology.     

Aspiration cytology of the oncocytic variant of papillary adenocarcinoma of the thyroid gland

OBJECTIVE: To study the cytologic features of the oncocytic variant of papillary adenocarcinoma of the thyroid gland to distinguish this subtype from other oncocytic lesions of the thyroid. STUDY DESIGN: We reviewed the smears from aspiration biopsies of 6 proven cases of oncocytic variant of papillary adenocarcinoma and compared their cytologic features with smears from 19 oncocytic follicular neoplasms (11 adenocarcinomas and 8 adenomas). Smears were stained with a modified Giemsa stain (Diff-Quik). RESULTS: All smears were cellular. Colloid was variable but more abundant in cases of the oncocytic variant of papillary adenocarcinoma. The cells in papillary adenocarcinoma had round to ovoid, overlapped nuclei; prominent intranuclear inclusions; and "grooves." Nucleoli were generally absent. In oncocytic follicular neoplasms, the cells had round nuclei and prominent nucleoli. Nuclear inclusions and grooves were seen but were not as prevalent as in papillary adenocarcinomas. CONCLUSION: The oncocytic variant of papillary adenocarcinoma of the thyroid gland can be distinguished from other oncocytic lesions by fine needle aspiration biopsy, whereas the absence of prominent nucleoli in oncocytes favors the diagnosis of an oncocytic papillary adenocarcinoma.     

Secretory carcinoma of the breast in an adult. Correlation of aspiration cytology and histology on the biopsy specimen

Needle aspiration was performed on the excisional biopsy specimen of a breast mass in a 63-year-old woman. The cytologic features in the aspirate included solid and papillary proliferations of tumor cells with abundant intracytoplasmic vacuolization and secretion. Histologic study of the lesion showed a secretory carcinoma. Although this is a rare breast neoplasm, especially in adults, the cellular features are characteristic and may permit a specific diagnosis on needle aspirates.     

Atypical follicular cells with equivocal features of papillary thyroid carcinoma is not a low-risk cytologic diagnosis

Objective: To determine whether or not significant differences in the risk of malignancy exist between subgroups of atypical follicular cells in The Bethesda System for Reporting Thyroid Cytology (TBSRTC) in patients who underwent surgical resection. Study Design: Between 2004 and 2009, consecutive thyroid fine-needle aspirates at our institutions with a cytologic diagnosis of 'atypical follicular cells' were retrieved and subclassified using the diagnosis and diagnostic comment as: (1) atypical follicular cells with equivocal features of papillary carcinoma [cannot exclude papillary thyroid carcinoma (PTC)] and (2) atypical follicular cells, other patterns. The risks of malignancy for excised nodules were calculated and comparisons were made between these subgroups. Categorical analysis was performed using a 2-tailed Fisher's exact test, and p < 0.05 was considered statistically significant. Results: A total of 7,072 thyroid fine-needle aspiration cases were retrieved, with 1,542 (21.8%) having a histologic follow-up. There were 222 (3.1%) cases of 'atypical follicular cells', with 127 (57.2%) having a histologic correlation and 33 having confirmed malignancies. Atypical follicular cells, cannot exclude PTC, have a significantly higher risk of malignancy than atypical follicular cells, other patterns (45.8 vs. 13.9%, p < 0.01). Conclusions: Atypical follicular cells with equivocal features of papillary carcinoma is not a low-risk cytologic diagnosis.     

Intrathyroidal Ectopic Thymic Tissue Mimicking Thyroid Cancer in Children

ObjectiveTo increase awareness of the important differential diagnosis between thyroid cancer and intrathyroidal ectopic thymic tissue when performing neck ultrasound (US) in pediatric patients.MethodsWe report 2 cases of intrathyrodal thymic tissue that were initially referred as possible papillary thyroid cancer (PTC). US and cytologic features of these lesions are described, and the distinguishing US characteristics of intrathyroidal thymic tissue versus PTC are discussed.ResultsTwo pediatric patients who underwent thyroid US were diagnosed with thyroid nodules suggestive of PTC. The suspected lesions in both patients exhibited an echo texture identical to the normal thymus gland. Fine-needle aspirate (FNA) biopsy of the nodule in the first case revealed numerous lymphocytes with positive immunocytochemical staining for CD3, confirming a T cell phenotype. The second patient underwent follow-up US imaging 8 months later that showed stability of the intrathyroidal nodule.ConclusionIntrathyroidal ectopic thymic tissue can be mistaken for PTC as both conditions have similar US features. Increased awareness of this unique mimicry may help to avoid unnecessary invasive investigations and surgery in these young patients. (Endocr Pract. 2014;20: e241-e245)     

Fine-needle aspiration of mucin-producing thyroid tumors

Objective: Mucin-producing thyroid tumors are extremely rare. Nonetheless, we have encountered three such cases in fine-needle aspiration. We report the cytologic and histologic findings and review the literature. Study Design: Cytologic features were studied on direct smears using Romanovsky stain to detect background substance and Papanicolaou stain to analyze nuclear and cytoplasmic features. The cytologic features were correlated with histology. Mucin was demonstrated by mucicarmine, Alcian Blue/PAS, and Alcian Blue (pH 2.5). Results: The cytologic features related to mucin include: (1) thick luminal mucin globules and signet ring cells aspirated from an 83-year-old woman with a 3-cm signet ring cell follicular adenoma, (2) abundant fluffy mucin containing signet ring cells in cohesive fragments aspirated from a 75-year-old man with the bilateral signet ring cell follicular variant of papillary carcinoma, which is the first case in the English literature, and (3) abundant thin mucoid mucin aspirated from the lymph node of an 86-year-old woman with a 5-cm mucinous poorly differentiated thyroid carcinoma. Conclusion: The occurrence of mucin in thyroid fine-needle aspiration does not necessarily indicate metastasis, and the presence of mucin in cervical lymph nodes does not exclude the thyroid gland as a possible primary.     

Expression of cytokeratin 19 and protein p63 in fine needle aspiration biopsy of papillary thyroid carcinoma

OBJECTIVE: To analyze the immunocytochemical distribution of CK19 and p63 on archival cytologic smears of 27 papillary thyroid carcinomas (PTCs), 22 benign thyroid lesions and 5 malignant non-PTC lesions. STUDY DESIGN: Archival cytologic smears of 27 papillary carcinomas, 22 benign thyroid lesions and 5 malignant nonpapillary carcinomas were processed for immunocytochemical detection of CK19 and p63, and results were compared. RESULTS: CK19 showed strong cytoplasmic staining in 22/27 fine needle aspiration biopsies (FNABs) of PTCs, in 5 benign lesions and in 4 malignant lesions of the control group. p63 Positivity was present in FNABs of 20/27 PTC and in 1 FNAB of nodular hyperplasia. Eighteen FNABs of PTC (66.6%) showed both strong CK19 staining and p63-positive cells, whereas none of the control cases showed coexpression of CK19 and p63. CONCLUSION: Coexistence of strong CK19 positivity and p63-positive cells can enhance the cytologic diagnosis of PTC.     

Cytopathology of the tall cell variant of thyroid papillary carcinoma.

The tall cell variant of thyroid papillary carcinoma differs from classic papillary carcinoma in its more aggressive clinical behavior, cell type (columnar amphophilic to oxyphilic) and higher frequency of stromal lymphoid infiltrate. A retrospective study of three such cases was made, with an emphasis given to the utility of fine needle aspiration cytology in their identification. Aspirates revealed papillary fronds and cyanophilic and oxyphilic neoplastic cells with a high proportion of nuclear grooves and cytoplasmic inclusions. These nuclear details allowed a specific diagnosis of papillary carcinoma with oxyphil cells as compared to oxyphilic cell follicular tumors. Smears from two cases showed, in addition, lymphoid cells and multinucleate giant cells. In them a diagnosis of coexisting Hashimoto's disease, granulomatous thyroiditis or inflammatory tumor stroma could not be excluded cytologically.     

Cytopathology of papillary carcinoma of the thyroid by fine needle aspiration

To delineate the cytologic presentation of papillary carcinoma of the thyroid, the fine needle aspiration smears were studied from 87 surgically proven cases. Six diagnostically useful findings were identified: papillary fronds, monolayered sheets, tissue fragments, intranuclear cytoplasmic inclusions, psammoma bodies and multinucleated giant cells. From 1,500 smears on "cold" nodules of the thyroid, 6 known false-negative and 4 false-positive diagnoses for papillary carcinoma were made. The estimated accuracy of the fine needle aspirate diagnosis of papillary carcinoma is 94%.     

Cystic Lymph Nodes in the Lateral Neck As Indicators of Metastatic Papillary Thyroid Cancer

ObjectiveTo determine whether radiographic findings portend to metastatic disease in patients with papillary thyroid carcinoma (PTC) and whether cystic lymph node metastasis can be recognized by preoperative, ultrasound-guided fine-needle aspiration (FNA).MethodsWe performed a retrospective review of patients with cystic lymph nodes in the lateral neck identified on preoperative ultrasonography between March 1996 and December 2009. Factors examined included demographic information; stage; cytologic and final pathologic findings; and imaging characteristics including location, size, and presence of vascularity and calcifications. Time of cystic node identification in relationship to initial diagnosis was also recorded.ResultsThirty patients had cystic lymph nodes in the lateral neck on cervical ultrasonography during the study period. Among this group, 28 (93%) had PTC, 1 (3%) had papillary serous carcinoma of the ovary, and 1 (3%) had poorly differentiated thyroid cancer. Median age at initial cancer diagnosis was 41 years (range, 16-64 years). Twenty-one patients (70%) were women, and median lymph node size was 1.8 cm (range, 0.6-4.8 cm). Twenty-three patients (77%) had a solitary cystic lymph node, and the remainder had more than 1 cystic lymph node. Cystic lymph nodes were identified at initial presentation in 11 patients (37%), while cystic lymph nodes were discovered in 19 patients (63%) after the initial operation. FNA was performed on the cystic lymph nodes of 23 patients (77%). Cytologic findings were positive for metastatic disease in 18 of 23 patients (78%). Among the 5 of 23 patients with negative cytologic findings, thyroglobulin aspirate was obtained in 1 patient, confirming metastatic PTC. Final pathologic review after surgical resection of cystic lymph nodes with negative cytologic findings from FNA was consistent with metastatic disease in 4 of 5 patients (80%).ConclusionsIn patients with PTC, the presence of a cystic lymph node by ultrasonographic examination is highly suggestive of locally metastatic disease. Confirmation of metastatic PTC may sometimes be achieved with thyroglobulin aspirate from cystic lymph nodes when cytologic findings are negative. Clinicians should strongly consider surgical lymph node resection of cystic lymph nodes regardless of the preoperative cytologic findings by FNA. (Endocr Pract. 2011;17:240-244)     

Cytologic diagnosis of vaginal papillary squamotransitional cell carcinoma. A case report

BACKGROUND: Papillary squamous and squamotransitional cell carcinomas of the cervix and vagina are infrequent morphologic variants of squamous cell carcinoma that may be underdiagnosed due to a bland histologic appearance. To our knowledge, this entity has not been previously detected by Pap smear evaluation. CASE: Vaginal wall pap smears were collected from a patient with a previous hysterectomy for microinvasive cervicovaginal squamous cell carcinoma and extensive carcinoma in situ. The smears were characterized by: (1) large, darkly staining, three-dimensional, branching, papillary epithelial fragments with prominent fibrovascular cores and lined with loosely cohesive epithelial cells; (2) a highly cellular background population of dissociated single epithelial cells with features of severe dysplasia, including hyperchromatic, coarse chromatin; scant, delicate, frayed cytoplasm and karyorrhectic debris; (3) syncytial aggregates of severely dysplastic epithelial cells morphologically similar to the single cells; and (4) lack of a recognizable, morphologically distinct "transitional cell" population. CONCLUSION: Papillary squamotransitional cell carcinoma of the vagina is a rare morphologic variant of squamous cell carcinoma that should be distinguished from benign vaginal squamous papillomas, condylomatous lesions and verrucous carcinoma. However, this lesion is also related to human papillomavirus infection, particularly the high-risk types. Papillary squamotransitional cell carcinoma can be suspected on Pap smear when high grade squamous intraepithelial lesion features are found in combination with three-dimensional papillary tissue fragments with prominent fibrovascular cores.     

Follicular variant of papillary carcinoma of the thyroid. A cytologic study of 15 cases

OBJECTIVE: To study the cytologic findings of follicular variant of papillary thyroid carcinoma (FVPTC) and to compare them with the cytologic findings on other thyroid lesions. STUDY DESIGN: The study group consisted of aspirate smears from 15 cases of histologically proven FVPTC. The control group consisted of 152 cases, including adenomatous colloid goiter (70), usual papillary carcinoma (40), follicular adenoma (30), Hürthle cell neoplasm (7) and medullary carcinoma (5). RESULTS: The smears of FVPTC revealed numerous colloid balls in the background, multilayered microfollicles (rosettes), numerous nuclear grooves and inclusions in the monolayer sheets of follicular cells, very rare giant cells, absence of calcification and papillary clusters. Rosettelike microfollicles and numerous colloid balls were not seen in the control group. CONCLUSION: The combination of numerous colloid balls and rosettelike microfollicles was frequently seen in FVPTC. This combination was not observed in the control group.