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.     

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.     

Needle track seeding of papillary thyroid carcinoma from fine needle aspiration biopsy. A case report

BACKGROUND: Dissemination of tumor cells from needle biopsy has been observed in a wide range of tumor types. Fine needle aspiration (FNA) biopsy has become accepted as the first-line test in the evaluation of thyroid nodules. Local recurrence of thyroid cancer from needle track seeding is an extremely rare complication of thyroid FNA. CASE: A 59-year-old woman developed local recurrence of papillary thyroid carcinoma three years after FNA of the primary cancer. Local metastases developed in the skin and sternocleidomastoid muscle. The location of the recurrent cancer and the linear relationship of the metastases indicated that local recurrence was due to needle track seeding at the time of FNA. CONCLUSION: Needle track seeding has been recognized as a possible, albeit rare, complication of FNA of thyroid cancer. Although proper FNA technique can reduce the potential for needle track seeding, its occurrence is an unavoidable complication of FNA evaluation of thyroid malignancies.     

Osteoclastomalike anaplastic carcinoma of the thyroid. Diagnosis by fine needle aspiration cytology

Fine needle aspiration (FNA) of a neck mass yielded cytologic specimens containing two cell populations: multinucleated giant cells and smaller, round-to-oval, undifferentiated malignant cells. The giant cells were frequently so numerous as to obscure the other cells. The FNA cytodiagnosis of a rare anaplastic thyroid carcinoma containing osteoclastic giant cells was substantiated by the subsequent exploratory surgery and biopsy specimen. Immunohistochemical staining suggested a dual origin of the two cell populations.     

Coexistent disease as a complicating factor in the fine needle aspiration diagnosis of papillary carcinoma of the thyroid

The occasional coexistence of papillary carcinoma of the thyroid with nodular goiter or hyperparathyroidism may in some cases result in a significant discrepancy between the clinical impression and the fine needle aspiration (FNA) biopsy diagnosis, leading to the suspicion that a false-positive FNA diagnosis was obtained. Two such cases are presented in which consultation between the cytopathologist and the surgeon was helpful in achieving a correct diagnosis and ensuring proper therapy. Awareness of these variations in the clinical presentation of papillary carcinoma of the thyroid will aid the cytopathologist in the resolution of such apparent discrepancies.     

Simultaneous occurrence of medullary and papillary carcinoma of the thyroid gland identified by fine needle aspiration. A case report

BACKGROUND: Fine needle aspiration (FNA) diagnosis of simultaneous medullary and papillary thyroid carcinoma in independent thyroid lobes is exceedingly rare. CASE: A 36-year-old female presented with a one-month history of dysphagia. Thyroid ultrasound revealed a multinodular goiter. She was clinically and biochemically euthyroid. FNA of the right thyroid nodule was consistent with medullary carcinoma, and FNA of the left thyroid lobe was consistent with papillary carcinoma. Immunohistochemistry revealed strong calcitonin and CEA positivity in the right lobe and lack of staining in the left lobe. Conversely, staining for thyroglobulin was negative on the right lobe and positive on the left lobe. CONCLUSION: The patient developed tumors in separate lobes of the thyroid. Immunoreactivity of calcitonin, CEA and thyroglobulin made a sharp distinction between the two tumors. Therefore, we conclude that these tumors were not linked by either embryology or genetics.     

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.     

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.     

Three-dimensional cytomorphology and its relationship with clinical stage in fine needle aspiration biopsy of papillary thyroid carcinoma

OBJECTIVE: To elucidate three-dimensional (3-D) cytomorphology and its relationship with clinical stage in fine needle aspiration biopsy (FNAB) of papillary thyroid carcinoma (PTC). STUDY DESIGN: FNAB was performed in tumors from 34 patients with PTC. The aspirate was stained and observed under a light microscope (LM). The aspirate was also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). Findings under SEM were correlated with the presentation under LM and also with clinical stage. As a control, FNAB was also performed on a normal part of the thyroid in six patients. RESULTS: Under SEM, normal thyroid cells appeared as round, scattered cells or sheets with a uniform honeycomb cellular arrangement. In PTC, cell sheets with uniform nuclear morphology under LM usually showed a uniform cell arrangement and with distinct cell borders under SEM. Cell sheets with nuclear pleomorphism under LM usually showed a more-disorganized arrangement and with indistinct cell borders under SEM. PTC at advanced clinical stages usually presented with a disorganized cell arrangement, indistinct cell borders and loss of microvilli. CONCLUSION: 3-D cytomorphology in FNAB of PTC was related to clinical stage and might be a prognostic factor for PTC.     

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.     

Parathyroid adenoma diagnosed as papillary carcinoma of thyroid on needle aspiration smears

Needle aspiration of a neck mass was performed on a 55-year-old white female with hypercalcemia. The cytologic material showed cohesive clusters of monomorphic hyperchromatic cells resembling follicular cells. Papillary formation and follicle-like arrangements suggested papillary carcinoma of the thyroid. The histopathologic section of the excised mass, however, revealed a parathyroid adenoma. The diagnostic difficulties in differentiating parathyroid adenoma from well-differentiated thyroid carcinoma are discussed. Data published in the literature emphasize similar difficulties, and it is concluded that a final diagnosis can be established only on histopathologic sections.     

Three-dimensional cytomorphology in fine needle aspiration biopsy of medullary thyroid carcinoma.

OBJECTIVE: To elucidate three-dimensional (3-D) cytomorphology in fine needle aspiration biopsy (FNAB) of medullary thyroid carcinoma (MTC). STUDY DESIGN: ENAB was performed on tumors from five patients with MTC. The aspirate was stained and observed under a light microscope (LM). The aspirate was also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). For transmission electron microscopy (TEM), the specimen was fixed, dehydrated, embedded in an Epon mixture, cut with an ultramicrotome, mounted on copper grids, electron doubly stained with uranium acetate and lead citrate, and observed with TEM. Findings under SEM were correlated with those under LM and TEM. RESULTS: Under SEM, 3-D cytomorphology of MTC displayed a disorganized cellular arrangement with indistinct cell borders in three cases. The cell surface was uneven and had granular protrusions that corresponded to secretory granules observed under TEM. In one case with multiple endocrine neoplasia type IIB, there were abundant granules on the cell surface. In one case of sporadic MTC with multinucleated tumor giant cells and small cells, granular protrusions also were noted on the cell surface. CONCLUSION: Granular protrusion was a characteristic finding in FNAB of MTC tinder SEM and might be helpful in the differential diagnosis.