Atypical cytologic features of medullary carcinoma of the thyroid. A review of 12 cases.

A total of 12 cases of medullary carcinoma of the thyroid were reviewed with regard to atypical cytologic features. They included clusters of cells with a follicular arrangement, papillary fronds, spindle-shaped cells, pleomorphic nuclei, nucleoli and intranuclear inclusions. Congo red staining on selected destained smears was positive for amyloid in three cases. Histology was also available in 12 cases. Two cases were incorrectly diagnosed as papillary carcinoma and one as follicular carcinoma on cytology. There were no false-positive diagnoses.     

Fine needle aspiration cytology of follicular variant of papillary carcinoma of the thyroid: Morphologic pointers to its diagnosis

OBJECTIVE: To study the cytomorphologic features of 59 cases of histologically proven follicular variant of papillary carcinoma (FVPC), compare them to those described in the literature and highlight cytologic features that may aid in the preoperative diagnosis. STUDY DESIGN: Aspiration smears from 59 histologically proven cases of FVPC were examined independently by 2 observers, and a detailed cytologic evaluation was done for architectural, cytologic and nuclear features. surgical RESULTS: On initial cytology of the 59 cases, 36 (61%) were diagnosed aspapillary carcinoma, and 17 of these were subtyped as FVPC. On reviewing the smears, 50 cases were diagnosed as papillary carcinoma, and 33 of them were typed as FVPC; however, 4 cases were diagnosed as benign lesions. Most smears showed moderate to high cellularity, with 55 cases (93%) showing syncytial clusters and 48 (81%) showing microfollicular architecture. Chromatin clearing and nuclear grooves were seen in 55 (93.2%) and 54 (91.52%) cases but were easily detected in only 36 (61%) and 44 (74%) cases, respectively. Thick colloid was identified in 28 cases, and 3 of these cases also showed thin colloid in the background. CONCLUSION: Our findings suggest that syncytial clusters, microfollicular architecture, chromatin clearing and nuclear grooves are strong morphologic pointers to the diagnosis of FVPC.     

Adenoid cystic pattern in follicular variant of papillary thyroid carcinoma: a report of four cases

S. Mandal, and S. Jain
Adenoid cystic pattern in follicular variant of papillary thyroid carcinoma: a report of four cases Objective: An adenoid cystic pattern in thyroid tumours is a rare finding that may be seen in papillary carcinoma of thyroid (PCT), the follicular variant of PCT (FV‐PCT), a rare cribriform‐morular variant of papillary carcinoma of thyroid (CMV‐PCT) and follicular carcinoma. There is little published cytological literature describing these patterns. We report four cases of PCT with this unusual pattern. Methods: Fine needle aspiration (FNA) cytology was performed on four patients with a neck lump using a 22‐G needle; smears were stained with Giemsa and Papanicolaou stains. Immunocytochemical staining for thyroglobulin was done in all cases. Results: The patients were female and ranged in age from 18 to 46 years. They presented with a gradually increasing mass in the neck. FNA smears in all cases showed nuclear features of PCT. There were also prominent follicular areas with hyaline globules in some of the cell clusters reminiscent of adenoid cystic carcinoma and, in places, morula‐like groups of neoplastic cells were also seen. Immunocytochemistry for thyroglobulin was positive in all cases but negative in the hyaline globules. Conclusions: Adenoid cystic areas with morula‐like groups in PCT are a rare finding. Cytopathologists and clinicians should be aware of these distinct features in thyroid tumours to avoid diagnosing metastatic adenoid cystic carcinoma. It is also important to rule out CMV‐PCT since that variant is mostly associated with familial adenomatous polyposis, although sporadic occurrence is known.     

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.     

Papillary breast lesions diagnosed on cytology. Profile of 65 cases

OBJECTIVE: To analyze the cytologic features of nipple discharge and fine needle aspiration (FNA) cytologic smears from breast lesions reported as showing papillary features and to correlate them with histopathologic features. STUDY DESIGN: The study group consisted of FNA smears and/or nipple discharge smears from 65 breast lesions diagnosed on cytology as duct papilloma, papillary lesion, fibrocystic condition, fibroadenoma, papillary neoplasm or papillary carcinoma. Cytomorphologic features assessed included cellularity, cell pattern (clusters, papillary, 3-dimensionality, etc.) and cell characteristics (monomorphism, pleomorphism, apocrine change, plasmacytoid features). Histological material was available for review and cytohistologic correlation in all cases. RESULTS: Forty-six specimens were FNA smears, and 16 were nipple discharge smears; in 3 cases FNA and nipple discharge cytologic smears were available for review. Cytologic study could predict the presence of a papillary pattern in all neoplasms with pure or focal papillary differentiation. There was an overlap in cytomorphologic features between papillary and nonpapillary benign lesions as well as between benign and malignant papillary neoplasms. Frank blood in the aspirate, cell dissociation and atypia, however, were more frequent in the last. CONCLUSION: Overlap of cytologic features in nonneoplastic and neoplastic benign papillary lesions and between benign and malignant papillary neoplasms necessitates histologic evaluation in all cases diagnosed as papillary on cytology. Since 49.2% of lesions showing papillary features on cytology prove to be malignant, all cases reported as papillary on cytology should be excised urgently for histologic assessment.     

Extracellular hyaline material in association with other cytologic features in aspirates from collagenous spherulosis and adenoid cystic carcinoma of the breast

OBJECTIVE: To reevaluate breast aspirates showing extracellular hyaline material (EHM) and globules to assess if clinicoradiologic and cytologic features could help in differentiating between benign and malignant lesions, especially collagenous spherulosis (CS) and adenoid cystic carcinoma (ACC). STUDY DESIGN: Fine needle aspiration was performed on 884 patients with breast lumps. The cytomorphologic features of 6 cases showing EHM, including classic hyaline globules (HGs), were analyzed in detail. Three cases also had hemorrhagic nipple discharge. Tissue diagnosis (4) and mammography (6) were available. RESULTS: Aspirate smears revealed high cellularity composed of monolayers: clusters of uniform, small cells; EHM; and HGs surrounded by similar cells. Benign naked nuclei and stromal fragments (4), nuclear pleomorphism (3), apocrine cells (2), foam cells (2), naked HGs (2) and spindle cells in proximity to HGs were also seen (4). Nipple discharge smears showed foam cells, erythrocytes (3) and epithelial cell clusters with hyaline material (1). The cytologic diagnosis was CS (4) and ACC (2). Histopathology confirmed the diagnosis of CS (2) and ACC (1). CONCLUSION: There may be a morphologic overlap between the cytomorphologic features of CS and ACC, leading to diagnostic errors. The presence of EHM and HGs in association with bland cellular features should be interpreted with caution to avoid erroneous diagnoses. Histopathology is mandatory in these cases because of their different prognostic implications.     

Fine needle aspiration in myxoid tumors of the soft tissues

Myxoid tumors of soft tissues constitute a histogenetically heterogeneous group of lesions, both benign and malignant, that show an overproduction of mucopolysaccharide substances. A correlative fine needle aspiration (FNA) cytologic and histologic study was performed on 16 such cases (3 intramuscular myxomas, 2 lipoblastomas, 6 myxoid liposarcomas, 4 myxoid malignant fibrous histocytomas [MFHs] and 1 extraskeletal myxoid chondrosarcoma), with electron microscopic examination of the aspirate in 4 cases. FNA of all tumors produced a gelatinous material. Smears from all but one of the tumors had a granular myxoid background substance that stained blue to blue-red with the Diff-Quik stain; the exception was the extraskeletal myxoid chondrosarcoma, whose smears stained intensely blue-red to red. On light microscopy, only lipomatous tumors had distinctive cells with diagnostic value: the lipoblasts. Although the arrangement of lipoblasts in lipoblastomas differed somewhat from that found in myxoid liposarcomas, clinical data were important for making a definitive diagnosis. Intramuscular myxomas generally showed a low cellularity composed of fibroblastlike cells with no cytologic atypia. Myxoid MFHs were composed of fibroblastlike cells and macrophagelike cells; the elongated cells with slight-to-moderate nuclear atypia predominated in tumors of low-grade malignancy, while polygonal or round cells with one or more nuclei and marked nuclear atypia predominated in high-grade tumors. Although extraskeletal myxoid chondrosarcoma was mainly differentiated from low-grade myxoid MFH by its metachromatic matrix, ultrastructural studies showed the distinctive distended cisternae with microtubular aggregates in the extraskeletal myxoid chondrosarcoma, thus contributing to the definitive diagnosis.     

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%.     

Fine needle aspiration cytology of lobular breast carcinoma. Comparison with other breast lesions

OBJECTIVE: To analyze the detailed cytomorphology of lobular breast carcinoma and to compare the cytologic smears of benign, borderline and infiltrating duct carcinoma. STUDY DESIGN: Fine needle aspiration cytology (FNAC) smears of histopathologically proven infiltrating lobular carcinoma (ILC), infiltrating ductal carcinoma (IDC), borderline lesions and benign breast lesions were selected for study. Detailed cytomorphologic analysis of the smears was carried out on hematoxylin and eosin- and May-Grünwald-Giemsa--stained slides, and a comparison of results was done. The various cytologic features were also graded semi-quantitatively with the numerical score; logistic regression analysis was done. RESULTS: There were 25 cases of ILC, 30 of IDC, and 10 borderline and 18 benign lesions. Cytologic diagnosis of malignancy on FNAC smears of ILC was offered in 19 cases; of them, 2 cases were diagnosed as ILC. The remaining six cases were diagnosed as borderline (four) and benign lesions (two). Overall sensitivity in detection of malignancy in ILC cases was 76%. FNAC smears of ILC showed moderate (52%) to abundant (32%) cellularity. The cells of ILC were arranged both in clusters and in dissociation (72%). Individual cells were monomorphic (40%) to mildly pleomorphic (60%), and the cells were smaller. The cells showed a smooth, regular nuclear margin; bland chromatin; and indistinct nucleoli. Indian file arrangement was frequently observed (28%). Nuclear molding (28%) and intranuclear inclusions (16%) were also noted. Intracytoplasmic lumina were seen in occasional cases. Logistic regression analysis was carried out, and a comparison between lobular carcinoma and ductal carcinoma, and borderline and benign lesions was done. Logistic regression analysis of cytomorphologic features showed that cellularity and nuclear margin irregularities were the two most important features to distinguish ILC from IDC. In comparison to borderline lesions, cell dissociation was more common in ILC. The salient cytologic features that helped to distinguish ILC from benign lesions was cell size, cellularity, cell uniformity and chromatin pattern. CONCLUSION: There are overlapping cytologic features between ILC, IDC and borderline breast lesions on FNAC smears. Logistic regression analysis may be helpful in this regard.     

Solitary nodular goiter. Review of cytomorphologic features in 441 cases.

OBJECTIVE: To study the cytomorphologic features of solitary nodular goiters (SNG). STUDY DESIGN: May-Grünwald-Giemsa-stained smears in 441 SNG diagnosed by ultrasonography and fine needle aspiration (FNA) and found to have optimum cellular material at review were subjected to detailed cytologic assessment. The age of the patients ranged from 11 to 75 years, with a median of 35. Male: female ratio was 69:372. The parameters for cytologic assessment included cellularity, colloid content, acinar formation, papillary formation, intranuclear cytoplasmic inclusions, nuclear grooves, marginal vacuoles, Hürthle cells and various inflammatory cells. Histopathology reports on thyroidectomy specimens were available in 27 cases from two Delhi hospitals. RESULTS: Hyperplastic nodules (68 cases) differed significantly from colloid goiters (269 cases) by having more cases with excessive cellularity, acinar formation and marginal vacuoles (P < .001). There was also a significant difference with respect to papillary formation and moderate-to-excessive colloid content (P < .001). As compared to hyperplastic nodules, neoplasms (60 cases) had a significantly higher number of cases with papillary formation, intranuclear inclusions and nuclear grooves but lower number of cases with marginal vacuoles (P < .01-.001). Among neoplasms, usual papillary carcinoma (19 cases) differed from follicular neoplasms (20 cases) with respect to acinar formation, papillary formation and nuclear grooves (P < .001). A significant difference was also observed with respect to colloid content and nuclear inclusions. Follicular variant of papillary carcinomas (FVPC) (10 cases) emerged as a distinct cytologic entity following review and differed from usual papillary carcinomas in having a higher number of cases with acinar formation, tubular formation and marginal vacuoles (P < .01-.001) and lower number of cases with nuclear grooves (P = .05). FVPC also differed from follicular neoplasms with respect to papillary formation, tubular formation, intranuclear inclusions and nuclear grooves (P < .01-.001). Overall cytohistologic agreement was achieved in 24 of 27 (88.9%) cases. CONCLUSION: Detailed cytologic assessment of FNA smears-in SNG was helpful in highlighting parameters that differentiate between various types of goiters.     

Columnar cell carcinoma of the thyroid. Fine needle aspiration findings in a case

Columnar cell carcinoma is a recently described rare tumor of the thyroid. The fine needle aspiration cytologic findings of one example are reported. In the smears, the tumor fragments showed papillary and glandular patterns. The tumor cells were columnar and exhibited pseudostratification of the nuclei. The nuclei were oval to elongated and possessed stippled chromatin and inconspicuous nucleoli; occasional ones exhibited longitudinal grooving. It is important to distinguish this tumor from papillary carcinoma of thyroid because of its much more aggressive behavior, from metastatic adenocarcinoma for obvious treatment considerations, and from medullary carcinoma.     

Morphometric image analysis of follicular lesions of the thyroid

OBJECTIVE: To determine the role of image morphometry in distinguishing various follicular lesions of the thyroid in cytologic smears. STUDY DESIGN: Archival fine needle aspiration smears of 10 cases each of follicular hyperplasia, follicular adenoma, follicular carcinoma and follicular variant of papillary carcinoma were used for the study. All cases were histopathologically proven. At least 100 random nuclei from each case were subjected to analysis with an image cytometer. Area, convex area, length, width, perimeter, convex perimeter and roundness of nuclei were measured using a 40 x objective (1 pixel = 0.446 micron). RESULTS: ANOVA showed that all the nuclear variables studied were significantly different (P < .05) in follicular hyperplasia as compared to follicular carcinoma and papillary carcinoma. All nuclear variables except roundness were also significantly different (P < .05) between follicular hyperplasia and follicular adenoma. However, between follicular adenoma, follicular carcinoma and papillary carcinoma there was considerable overlap of nuclear morphometric parameters. CONCLUSION: Image morphometry may help to distinguish nonneoplastic follicular lesions (hyperplasia) from neoplastic lesions (adenomas and carcinomas). However, to distinguish benign from malignant follicular lesions, image morphometry might not improve the accuracy of standard cytologic examination.     

Nuclear grooves in the aspiration cytology of papillary carcinoma of the thyroid

Nuclear grooving has recently been shown to be a useful morphologic feature in the diagnosis of papillary carcinoma of the thyroid in tissue sections and imprint smears. In order to assess the diagnostic value of nuclear grooving in cytologic specimens, the presence of this feature was evaluated in fine needle aspirates from 20 papillary carcinomas of the thyroid, 10 follicular adenomas, 3 follicular carcinomas, 1 medullary carcinoma, 10 nodular goiters and 4 cases of Hashimoto's thyroiditis. In each case, 30 random high-power fields (HPFs), or all fields in less cellular smears, were examined, and the percentage of the fields in which nuclear grooving could be seen was recorded. Seventeen of 20 papillary carcinomas (85%) showed nuclear grooves in more than 25% of the HPFs examined; in the remaining three cases, grooves were observed in less than 25% of the HPFs. In control cases (all other thyroid lesions), nuclear grooves either were absent or were present in less than 25% of the HPFs examined. These findings suggest that nuclear grooving, when seen in abundance, can be considered a reliable criterion for the diagnosis of papillary carcinoma in fine needle aspiration cytology of the thyroid. The presence of occasional grooves, however, should be regarded as a nonspecific finding.     

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.     

Cytologic features of clear cell carcinoma of the female genital tract. Diagnostic value of the "raspberry body" in nonexfoliative cytologic specimens

OBJECTIVE: To evaluate the presence of basement membrane stromal material in fine needle aspiration (FNA) and scrape cytologic specimens from patients with clear cell carcinoma (CCC) of the female genital tract. STUDY DESIGN: The study group consisted of 6 patients with CCC (5 ovarian and 1 cervical). Four samples corresponded to FNA specimens and 3 to scrape material obtained during intraoperative consultation for ovarian tumors. FNA was performed on a pelvic recurrence and on liver, pulmonary and lymph node metastases. The 6 cases had a complete histopathologic study. RESULTS: In addition to large, clear cells, all cases showed basement membrane stromal material that assumed several forms. The most common was globular, hyaline structures, either naked or surrounded by neoplastic epithelial cells ("raspberry bodies"). Other fragments were larger, with several spherules and elongated prolongations. Scrape material showed stromal material resembling reduplicated basement membrane material. In Diff-Quik-stained smears (QCA, Tarragana, Spain) it showed metachromatic staining with a pink to purple color. Its recognition on Papanicolaou-stained smears was more difficult since it did not stain or was gray. CONCLUSION: Basement membrane stromal material and, more precisely, "raspberry bodies," are a characteristic cytologic feature of CCC of the female genital tract. The combination of clear, atypical cells and basement membrane stroma is highly specific to this neoplasm and can be observed not only in exfoliative specimens but also in FNA and scrape samples.     

Expression of CD44 and cyclin D1 in fine needle aspiration cytology of papillary thyroid carcinoma

OBJECTIVE: To compare the expression pattern of CD44 and cyclin D1 immunostaining in fine needle aspiration specimens of papillary carcinoma of the thyroid and nonpapillary lesions. STUDY DESIGN: The study was performed on 80 fine needle aspiration cytologic smears of thyroid lesion retrospectively using monoclonal antibodies and on histologic material from a proportion of cases. RESULTS: Most papillary carcinomas expressed intense cell membrane or diffuse cytoplasmic staining for CD44 (97.8%). Focal immunoreactivity was observed in follicular neoplasms (28.5%) and nodular goiter (4.7%). There was no difference in CD44 immunostaining between follicular carcinoma and adenoma. Cyclin D1 was expressed in the nuclei of most papillary carcinomas (79.2%). Focal nuclear immunoreactivity was noted in nodular goiters (23.5%) and follicular neoplasms (10%). In resected specimens, all papillary carcinomas (19 cases) showed intense membranous or granular CD44 immunoreactivity. Focal cyclin D1 expression was noted in 52.6%. There was no difference in CD44 and cyclin D1 expression between the group of papillary carcinomas with regional lymph node metastasis as compared to those without metastasis. Positive staining for both CD44 and cyclin D1 would strongly favor papillary carcinoma, although further studies on cytologic material are necessary to verify this diagnostic approach. CONCLUSION: Most papillary carcinomas express CD44 and cyclin D1, whereas it is less common in follicular neoplasms and nodular goiter. This may be helpful in diagnostically difficult cases.     

Cytology of collagenous spherulosis of the breast: a diagnostic dilemma – report of three cases

Collagenous spherulosis is a rare incidental finding seen in association with benign breast lesions. Cytological findings in three cases of collagenous spherulosis diagnosed on fine needle aspiration are presented. The presence of hyaline pink globules surrounded by benign myoepithelial cells in Giemsa stained smears was a diagnostic feature. Associated lesions were atypical papillary hyperplasia (2) and fibroadenoma (1). Adenoid cystic carcinoma was the close differential diagnosis on cytology. Awareness of this entity is important to avoid a false positive diagnosis of malignancy.     

Cribriform-morular variant of papillary thyroid carcinoma. Report of a case showing morules with peculiar nuclear clearing

BACKGROUND: There have been only 4 reported cases of cribriform-morular variant of papillary thyroid carcinoma (CMVPTC) with cytologic findings from fine needle aspiration. In these reports, the cytologic findings do not fully reflect the histologic characteristics of this entity. We report a case of CMVPTC in which a cribriform pattern without colloid and epithelial morules with peculiar nuclear clearing (PNC) were present in smears, thus fulfilling the criteria for a cytologic diagnosis of CMVPTC. Protein truncation tests for APC molecule abnormality indicated the presence of germline mutation in the patient's APC gene. CASE: A 30-year-old woman had multiple thyroid tumors. Aspiration cytology revealed a large number of round to spindle-shaped atypical-cells showing sheet-like, cribriform, follicular, whorl-like and solid, 3-dimensional arrangements. The cribriform and follicular arrangements did not contain colloid in the lumen. The powdery chromatin pattern characteristic of papillary carcinoma was not observed, but there were scattered intranuclear cytoplasmic pseudoinclusions and grooved nuclei. The nuclei of the atypical cells presenting in the whorl formations showed enlargement, thickened nuclear membranes and entirely clear contents, consistent with PNC. Hyalinelike necrotic cells were also observed in the cell clusters or in the background. Histologic and immunohistochemical findings were typical of CMVPTC. CONCLUSION: The cribriform pattern without colloid, fascicular or whorl formation of spindle cells, and morules with PNC are identifiable on cytologic smears and are sufficiently distinctive to allow a cytologic diagnosis of CMVPTC.     

Papillary carcinoma of the breast. Cytologic study of nine cases.

OBJECTIVE: To study the cytologic findings of papillary breast carcinoma by fine needle aspiration. STUDY DESIGN: The study group consisted of fine needle aspiration (FNA) specimens of breast tumors from nine patients performed during the period 1988-1997. Eight were female, and one was male. The FNA results were compared with the final histologic diagnosis. RESULTS: The tumor sizes were 4-6.5 cm. The aspirations yielded a good amount of bloody material. The smears revealed high cellularity, papillary clusters, isolated low-to-tall columnar cells, mild to moderate atypia, hemorrhagic background, foam and hemosiderin-laden macrophages, calcification, rare mitoses, palisading row of cells and bipolar cytoplasmic eosinophilic granules. The smears were diagnosed as either suspicious or suggestive of papillary carcinoma. The histologic examination revealed invasive papillary carcinoma. CONCLUSION: Papillary carcinoma of the breast can be diagnosed by using a panel of cytologic findings that includes hypercellularity, papillary clusters, hemorrhagic background, palisading rows of tall columnar cells, cellular atypia and calcification. The interesting finding in this study was the presence of eosinophilic bipolar cytoplasmic granules, which has not been reported before.     

Fine needle aspiration cytology of follicular variant of papillary carcinoma of thyroid

In this retrospective study, we tried to ascertain the fine needle aspiration cytology (FNAC) features of six histopathologically proven cases of the follicular variant of papillary carcinoma of thyroid (FVPCT). These proven cases were diagnosed from 1998-2000. May-Grunwald-Giemsa and haematoxylin & eosin stained FNAC smears were studied independently by two observers (MP and PD) for detailed cytological features. A comparison of the cytological features was undertaken with those reported in the literature. There were six cases of which only one case was diagnosed as FVPCT while the other five cases were diagnosed as follicular neoplasm (four cases) and neoplasm unclassifiable (one case) on FNAC smears. All these cases showed abundant cellularity with a prominent follicular pattern. No papillae were identified in any of the cases. Syncytial clusters (five cases), nuclear grooves (six cases), nuclear inclusions (one case) and chewing gum colloid (three cases) were noted in variable proportions. We suggest that a differential diagnosis of FVPCT should be considered if the cytology smears show abundant cellularity, syncytial clusters and follicular arrangement along with thick colloid.