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.     

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.     

Aspiration cytology of renal-cell carcinoma metastatic to the thyroid

Fine needle aspiration (FNA) of a thyroid mass clinically suspected of being acute thyroiditis led to a cytologic diagnosis of hypernephroma metastatic to the thyroid and to the subsequent detection of the occult primary tumor. The FNA cytomorphologic findings were substantiated by cytochemical staining of FNA samples and confirmed by subsequent histopathologic examination of the resected thyroid. Postoperative studies revealed an expansive growth in the left kidney; analysis of the nephrectomy specimen showed an invasive renal-cell carcinoma. This case emphasizes the considerable value of FNA biopsy in making the frequently difficult preoperative differential diagnosis of primary and metastatic thyroid tumor and the importance of cytochemical analyses in making that distinction and in suggesting the site of the primary tumor.     

Bilateral pheochromocytoma associated with papillary adenocarcinoma of the thyroid gland; report of an unusual case

A 31-year old woman was admitted to our clinic complaining of high blood pressure, dizziness, constipation, mental irritability and weight loss. The physical examination revealed goiter in her neck. The plasma levels of norepinephrine and epinephrine were 3.45 and 0.76 ng/ml, respectively. Urinary excretion of norepinephrine was 1 mg and epinephrine was 32.2 micrograms/24-hours. The examination by radiography and radioactive isotope revealed a tumor in the left adrenal region and another in the left lower lobe of the thyroid. After the operations, pheochromocytoma and papillary adenocarcinoma of the thyroid gland were recognized pathologically. However, 17 months later, the recurrence of pheochromocytoma in the contralateral adrenal region was discovered and removed. Although the co-existence of bilateral pheochromocytoma and papillary adenocarcinoma of the thyroid gland is not one of multiple endocrine neoplasia, to the best of our knowledge, only 7 such cases have been reported in the published literature.     

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.     

A low-power, "architectural," clue to the follicular variant of papillary thyroid adenocarcinoma in aspiration biopsy

OBJECTIVE: To search for low-power, or "architectural," clues to the diagnosis of the follicular variant of papillary thyroid adenocarcinoma (FVP) in Diff-Quik-stained aspiration biopsy smears in order to aid in the rapid diagnosis of FVP, especially as a complement to frozen sections. STUDY DESIGN: The smears of 23 cases, each with tissue-proven FVP, were compared to those of 23 cases of classic papillary thyroid adenocarcinoma (PTA), 23 cases of tissue-proven follicular neoplasms (FN) (i.e., adenoma or well-differentiated adenocarcinoma) and 23 samples of colloid nodules (CN). The low-power (10x) features of the four groups were studied and compared. RESULTS: Our study showed that FVP exhibited monolayered cellular sheets with branched, irregular contours, which can be distinguished from the uniform microfollicles with smooth contours formed in FN and the large, round or oval monolayered sheets of follicular cells found in CN. FVP shared all of the features of classic PTA except for the larger, complex sheets of epithelial cells and psammoma bodies found in the latter. CONCLUSION: The branched sheets of epithelial cells evident during low-power examination of Diff-Quick-stained smears of thyroid aspirates are a ready first clue to the rapid diagnosis of FVP. The diagnosis can be confirmed by subsequent careful evaluation of nuclei in Papanicolaou-stained smears and sections of tissue.     

Fine needle aspiration cytology of thyroid gland diseases

From 1982 to 1987, 2,433 lesions of the thyroid gland in 1,796 patients were examined by fine needle aspiration (FNA). Cytopathology classified 66.91% of the aspirates as benign, 10.76% as thyroiditis, 4.89% as suspected (unspecified) neoplasia, 1.31% as positive for malignancy and 16.11% (392) as unsatisfactory. The histologic diagnoses in 257 cases were compared with cytologic diagnoses to determine the accuracy of FNA cytology of thyroid lesions, yielding a sensitivity of 71.43%, a specificity of 100% and an accuracy of 95.09%. This data strongly supports thyroid FNA as an important preoperative diagnostic tool. Follicular carcinomas were difficult to cytologically differentiate from nonmalignant follicular neoplasms, and papillary thyroid carcinomas less than 2 cm in diameter in elderly patients were frequently misdiagnosed or diagnosed only as "suspect lesion."     

Renal-cell carcinoma metastatic to the thyroid. Aspiration cytology and histologic findings

A case of renal-cell carcinoma metastatic to the thyroid eight years after the removal of the primary tumor is presented, with the aspiration cytologic and histologic findings described. This unusual presentation and the incidence and behavior of renal-cell carcinomas and tumors metastatic to the thyroid are discussed.     

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.     

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.