Follicular variant of papillary thyroid carcinoma: a diagnostic challenge for clinicians and pathologists (original) (raw)
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JAMA otolaryngology-- head & neck surgery, 2014
The follicular variant (FV) of papillary thyroid carcinoma (PTC) is an important subtype that can be difficult to diagnose using preoperative cytologic analysis. To compare conventional and FV PTC with regard to preoperative cytologic diagnosis using a tiered thyroid cytologic reporting system, tumor size at diagnosis, presence of invasion, and implications on prognostic scores. This retrospective study was conducted in an academic teaching hospital and included 99 patients with conventional (n = 65) or FV (n = 34) PTC. Preoperative thyroid cytologic findings, originally reported using the tiered British Thy system, were recategorized according to the Bethesda classification system. Pathologic features recorded included tumor size, presence of extrathyroid extension (ETE), and metastases. Prognostic scores were calculated according to the MACIS system. Differences in patient demographics, preoperative cytologic findings, tumor pathologic features, and prognostic risk categories betw...
Follicular Variant of Papillary Thyroid Carcinoma
Acta Cytologica, 2005
Between 1990 and 2003, 92 patients with follicular variant of papillary carcinoma (group A) were enrolled in a long-term study and compared with control groups of follicular thyroid carcinoma (group B, 40 cases) and pure papillary thyroid carcinoma (group C, 99 subjects).
Bangladesh Medical Research Council Bulletin, 2017
A significant increase in incidence of papillary thyroid carcinoma (PTC) has been noticed in recent decades worldwide. This is due to advances in medical surveillance, increased use of ancillary tests, and a minor component due to over diagnosis of PTC. Follicular variant of papillary thyroid carcinoma (FVPTC) is the second most common variant of PTC and comprises about 23-41%. It is difficult to diagnose histologically when the distinctive nuclear features are either not well developed or present focally within the lesion. Several immunohistochemical markers (CD56, HMCK, GAL3, HBME-1 and CK19) either alone or combined in panels can be used to improve diagnostic accuracy. This study was aimed to differentiate FVPTC from other follicular patterned lesion of thyroid by histopathology and immunohistochemistry (IHC). A total of 50 histologically diagnosed cases of thyroid neoplasm were studied. The neoplastic cases included 40 cases of follicular variant papillary carcinoma (FVPC), 04 classic papillary carcinoma (PTC), 04 follicular carcinoma and 02 follicular adenoma. All cases were evaluated by IHC for the expression of CD56 and CK19 antibody. In case of FVPTC (n=40), 21 cases (52.5%) were CK19 positive and CD56 negative as expected. Both markers were found positive in 06 (15%) cases and CD56+ alone was found positive in 11 (27.5%) cases of FVPTC, and a finding that goes against the diagnosis of FVPTC. The histopathological slides of these cases were reviewed and findings were recorded. All cases (n=4) of classic PTC were CK19 positive and 03 (75%) cases were found CD56 negative. Diagnoses of thyroid follicular lesions are primarily based on histological and cytomorphological criteria. However, there was a subset of follicular patterned tumors like FVPTC which lack unequivocal features of malignancy. Immunohistochemistry can improve diagnostic accuracy but needs additional studies for controversial cases. It may be considered these lesions as differentiated tumor of uncertain malignant potential (WDT-UMP) to avoid the using term carcinoma. Additional studies are needed for establishing more precise morphologic criteria and for identifying useful markers for differentiating benign from borderline or malignant thyroid lesions.
Journal of Endocrinological Investigation, 2015
rate was significantly higher in patients with CPTC than in those with FVPTC. The local recurrence rate in patients <45 years was not significantly different between the two groups of patients. The multicentricity rate was significantly higher in the FVPTC group for both age groups. Dynamic risk assessment showed that the rate of intermediate-and high-risk groups showed no significant difference between C-PTC and FVPTC patients but the rate of low risk patients was higher in FVPTC group than in C-PTC group (p = 0.04). The recurrence rate in low-risk group was found higher in C-PTC compared to FVPTC patients (4.7 vs. 0.7 %, p = 0.04, respectively). The recurrence rate showed no significant difference in both intermediate-and high-risk groups in C-PTC and FVPTC patients. During the follow-up, the rate of distant metastasis and diseasespecific mortality was not significantly different between the two groups (p = 0.25). Conclusion FVPTC is a common subtype of PTC and has a higher rate of multicentricity with bilobar involvement. Although aggressive histopathologic features, such as thyroid capsule invasion, extrathyroidal extension, and lymph node metastasis, are significantly more frequent in CPTC than in FVPTC, the long-term outcome is similar in both subtypes after appropriate initial surgery and postoperative RAI ablation treatment.
Cancer Cytopathology, 2017
BACKGROUND: The noninvasive follicular variant of papillary thyroid carcinoma (PTC) has an indolent clinical behavior in comparison with other PTCs, including the invasive follicular variant of papillary thyroid carcinoma (IFVPTC). Recently, the term noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was introduced to emphasize the low biological potential of these tumors. This study compares clinical, cytological, and molecular features of NIFTP and IFVPTC. METHODS: The study consisted of 97 thyroid fine-needle aspiration biopsy (FNAB) cases with corresponding surgical pathology from the pathology archives of the Massachusetts General Hospital. The collected patient data included the following: age, sex, type of surgery, tumor size, and prior cytological diagnosis with The Bethesda System for Reporting Thyroid Cytopathology. A molecular analysis using anchored multiplex polymerase chain reaction was performed for all cases. Each case was reviewed and subclassified histologically as NIFTP or IFVPTC. Cytology slides were scored semiquantitatively for nuclear atypia. The statistical analysis was performed with the nonparametric Mann-Whitney test. RESULTS: The 97-case cohort consisted of 50 NIFTP cases and 47 IFVPTC cases, including 18 encapsulated IFVPTC cases and 29 nonencapsulated IFVPTC cases. Differences in the type of surgery (P 5.0399), molecular features (P 5.0141), cytological classification (P 5.0266), and nuclear scores (P 5.0141) between NIFTP and IFVPTC were observed. There was overlap in the cytological classification of NIFTP and IFVPTC; however, NIFTP was more often classified as atypia of undetermined significance/follicular lesion of undetermined significance or follicular neoplasm/suspicious for follicular neoplasm in comparison with both subsets of IFVPTC. NIFTP was primarily associated with mutations in RAS, whereas an equal number of IFVPTC cases were associated with BRAFV600E or with RAS mutations. CONCLUSIONS: Despite differences in the cytological classification and molecular profiles between NIFTP and IFVPTC, the degree of overlap makes it unlikely that most cases of NIFTP and IFVPTC can be accurately distinguished with FNAB. Cancer Cyto
World Journal of Surgery, 2006
Introduction: The follicular variant of papillary thyroid carcinoma (FVPTC) is the most common histologic subtype of papillary thyroid carcinoma (PTC). However, it is still controversial whether FVPTC should behave differently from classical PTC (CPTC). The present study aimed at evaluating any potential difference in clinicopathologic features and long-term outcome of FVPTC as compared with CPTC. Patients and Methods: Of 568 patients with PTC managed from 1973 to 2004, 308 were shown to have CPTC (54.2%) and 67 (11.8%) FVPTC after histologic review. The mean (-SD) follow-up period was 11.3 (-8.9) years. The two groups were compared in terms of clinicopathological features, treatment received, and outcome regarding recurrence and disease-specific survival. Results: There was no difference in age and gender ratio between the CPTC and FVPTC patients. Both groups had similar tumor characteristics in terms of tumor size, presence of multifocality, capsular invasion, lymphovascular permeation, and perineural infiltration. However, FVPTC patients had significantly fewer histologically confirmed cervical lymph node metastases (P = 0.027) and extrathyroidal involvement (P = 0.005). The proportion of bilateral resection, adjuvant radioactive iodine, and lymph node dissection did not differ significantly between the two groups. The FVPTC patients had a more favorable tumor risk by DeGroot classification (P = 0.003) and MACIS (Metastasis, Age, Completeness of excision, Invasiveness, and Size) score (P = 0.026). The 10-and 15-year actuarial disease-specific survivals did not differ significantly between FVPTC and CPTC patients (96.2% versus 90.7% and 96.2% versus 89.1%, respectively). Conclusions: Although patients with FVPTC had more favorable clinicopathologic features and a better tumor risk group profile, their long-term outcome was similar to that of CPTC patients. P apillary thyroid carcinoma (PTC) is the most common type (70%-80%) of thyroid carcinoma and is generally associated with an excellent prognosis. Over the past decades, it has been increasingly recognized that the conventional or classical type of PTC (CPTC)
Virchows Archiv, 2002
In an attempt to advance and improve the characterization of the so-called diffuse follicular variant of papillary thyroid carcinoma (diffuse FVPTC) we studied a series of 59 thyroid carcinomas consecutively treated in a specialized center. The clinicopathologic and some of the immunohistochemical characteristics (uPA-R, Lewis X, Sialyl Lewis X, and MIB-1) of ten cases of FVPTC displaying a multinodular or diffuse pattern of growth, and histologic features similar to those previously described in diffuse FVPTC, were compared with those of common papillary thyroid carcinoma (PTC, 25 cases) and common FVPTC (8 cases). Cases of diffuse FVPTC differed significantly from common PTC and FVPTC in targeting younger patients and in exhibiting a prevalence of multicentricity, extrathyroid extension, nodal metastasis, and vascular invasion. Immunohistochemically, diffuse FVPTC cases were characterized by the overexpression of uPAR and sialyl Lewis X. No differences were observed regarding MIB 1 immunoreactivity. Regardless of the term used to designate the multicentric, invasive form of FVPTC (diffuse or multinodular FVPTC) it is crucial to acknowledge the existence of cases of FVPTC with a guarded prognosis that should be distinguished from the classic, uninodular form of FVPTC.
Annals of Surgical Oncology, 2014
Background. There are three subtypes of follicular variant papillary thyroid carcinoma (fvPTC): completely encapsulated, well circumscribed, and infiltrative. While infiltrative tumors are more aggressive than completely encapsulated, controversy exists regarding management of fvPTC subtypes. We compared the clinicopathologic features of fvPTC subtypes to those of classic PTC (cPTC) to help guide fvPTC management, using cPTC as a reference. Methods. A retrospective review was performed on 316 patients with PTC treated at a single institution from 2004 to 2011. There were 197 cPTC and 119 fvPTC tumors, including completely encapsulated (n = 46), well circumscribed (n = 46), and infiltrative (n = 27). Clinicopathologic data were compared between groups. Results. fvPTC patients had larger tumors than cPTC patients (1.6 cm vs. 1.2 cm, p = 0.001), but age, sex, and family history did not differ. Thirty-one percent of cPTC tumors had extrathyroidal extension compared to 0 % of completely encapsulated, 0 % of well-circumscribed, and 52 % of infiltrative fvPTC tumors (p \ 0.05). Central lymph node metastasis occurred in 50 % of cPTC compared to 0 % in completely encapsulated, 20 % in wellcircumscribed, and 72 % in infiltrative fvPTC tumors (p \ 0.05). Notably, lymph node metastasis was significantly lower in completely encapsulated than in wellcircumscribed tumors, without a difference in the median number of nodes sampled. There were no differences in lymphovascular invasion or extranodal extension.
The diagnostic dilemma of follicular variant of papillary thyroid carcinoma* 1
Surgery, 2003
Background. Given the difference in surgical management between follicular neoplasms and papillary thyroid carcinoma (PTC), we sought to determine the sensitivity of fine-needle aspiration (FNA) and intraoperative pathologic study (IP), frozen section and cytologic study, in establishing a diagnosis of follicular variant of papillary thyroid carcinoma (FVPTC) and how these techniques impact operative management. Methods. A retrospective chart review was performed of patients who underwent thyroidectomy for nodular disease between June 1997 and June 2002 identifying patients with a final diagnosis of FVPTC. FNA and IP results were reviewed in this group of patients and correlated with those of final histopathologic study. The sensitivity of FNA and IP was calculated. Results. Eighty-two patients had a final diagnosis of FVPTC. Eighty-six preoperative FNAs were obtained in 80 patients, leading to a diagnosis of PTC in 7 (sensitivity 9%). Intraoperative pathologic study was performed in 31 patients with suspicious FNA results, of which 13 were definitive for PTC (sensitivity 42%). Overall, IP was obtained in 42 patients, of which 15 were positive for PTC (sensitivity 36%). Conclusion. Although the sensitivity of FNA in establishing a diagnosis of FVPTC is low, FNA identifies patients with suspicious lesions in whom IP is important in guiding operative management. (Surgery 2003;134:1005-12.