Papillary Hürthle cell carcinoma (Warthin-like tumor) of the thyroid. Report of a case with fine needle aspiration findings

Cytological features of warthin-like papillary thyroid carcinoma: A case report with review of previous cytology cases

Warthin-like papillary thyroid carcinoma (WLPTC) is a rare morphological variant of papillary thyroid carcinoma which mimics various benign and malignant lesions on thyroid aspiration cytology. As correct cytological diagnosis is the cornerstone for appropriate patient management, awareness of the salient cytomorphological characteristics of this tumor is essential. Here, we present cytological features of a case of WLPTC along with discussion of the common differential diagnoses and a brief review of the literature to ascertain the most consistent cytological findings of WLPTC. The present case also harboured BRAFV600E mutation which is the commonest molecular alteration seen in WLPTC.

Cytomorphologic Diversity of Papillary Thyroid Carcinoma

Introduction:

Cytologic features of papillary thyroid carcinoma (PTC) have been extensively documented in literature. However, PTC variants can prove to be diagnostically challenging on fine needle aspiration cytology (FNAC).

Aims:

To study the FNAC features of PTC and its variants and explore the causes for misdiagnosis.

Materials and Methods:

This is a retrospective study. All cases of histopathologically (HP) confirmed cases of PTC during a 2-year period (January 2012 to December 2013) with presurgical FNAC were included. The cytologic findings and FNAC diagnosis of each case were documented and compared with the HP report. The misdiagnosed cases were reviewed to look for any cytological clues and reasons for misdiagnosis.

Results:

A total of 58 cases were included. The overall diagnostic accuracy was 55.6% which improved to 64.8% on including suspicious for PTC cases. Follicular variant was the most misdiagnosed variant; 41.2% of the cases were called follicular neoplasm. Oncocytic variant showed cells with abundant eosinophilic cytoplasm along with bizarre giant cells. Warthin tumor-like variant showed cells with moderate eosinophilic cytoplasm with close apposition of lymphocytes in a background of reactive lymphocytes and lymphoid tangles. Cystic variant was paucicellular. Columnar cell variant showed tall columnar cells with nuclear stratification. Cribriform–morular variant showed syncytial sheets of cells and hyaline globules.

Conclusions:

PTC variants have distinct cytomorphological features. In some variants (follicular, columnar cell), nuclear grooves and inclusions may not be apparent, contributing to the diagnostic confusion. Benign nodule adjacent to the tumor can dominate the FNAC smear and lead to misdiagnosis.

Sonographic and cytopathologic correlation of papillary thyroid carcinoma variants

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer and constitutes more than 70% of thyroid malignancies. Although TNM staging is the most widely used parameter for determination of therapeutic plans, recent studies have suggested that different histopathologic variants of PTC can also have different clinical courses and patient prognoses. Sonographic criteria for PTC are well established and include a taller-than-wide shape, an irregular margin, microcalcifications, and marked hypoechogenicity. The role of sonography has expanded to enable the characterization of PTC variants based on their sonographic features. Tall cell and diffuse sclerosing variants appear to have more aggressive clinical courses with unfavorable prognoses, whereas the more recently described cribriform-morular and Warthin-like variants have relatively indolent clinical courses. The prognoses of patients with follicular, solid, columnar cell, and oncocytic variants are still controversial and may be similar to the prognosis of conventional PTC. Understanding the sonographic characteristics of PTC variants with clinicopathologic correlation may be helpful for suggesting an appropriate treatment plan.

Warthin-like variant of papillary thyroid carcinoma: single institution experience

BACKGROUND

Correct diagnosis of the variants of papillary thyroid carcinoma (PTC) is important because these variants differ in clinical course. The Warthin-like variant (WLV) is relatively uncommon and is recognized as not different from conventional PTC. We therefore assessed the clinicopathological features of patients with WLV of PTC who were diagnosed and treated at our institution.

METHODS

Of the 8179 patients treated for PTC at the Thyroid Cancer Center, Gangnam Severance Hospital, Yonsei University College of Medicine, between January 2007 and December 2012, 16 patients (0.2%) were pathologically diagnosed with WLV of PTC. Their clinicopathological features and post-operative follow-up for local recurrence and distant metastasis were retrospectively investigated.

RESULT

Mean patient age was 44.9 years (range: 23-61 years), with seven (44%) being younger than 45 years. Only one of the 16 patients was male (6%). Mean tumour size was 8.9 mm (range: 3-22 mm). Extrathyroidal extension was observed in seven patients (44%), associated thyroiditis in 11 (69%) and lymph node metastasis in six (38%). The mean follow-up period was 37 months (range: 13-78 months), during which none of the 16 patients experienced recurrence or metastasis. Fifteen patients (94%) had MACIS score <6, with the remaining patient having a MACIS score of 6.33.

CONCLUSION

WLV of PTC is rare, with favourable prognosis. Nevertheless, it is important to determine the histopathological features of these tumours.

Diagnostic terminology and morphologic criteria for cytologic diagnosis of thyroid lesions: a synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine-needle Aspiration (FNA) State of the Science Conference on October 22-23, 2007 in Bethesda, MD. The two-day meeting was accompanied by a permanent informational website and several on-line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters regarding diagnostic terminology/classification scheme for thyroid FNA interpretation and cytomorphologic criteria for the diagnosis of various benign and malignant thyroid lesions. (http://thyroidfna.cancer.gov/pages/info/agenda/).

Warthin-like tumor variant of papillary thyroid carcinoma: case report and literature review

A tumor approximately 4.0 x 3.0 cm in size with a cystic change was observed in the left lobe of the thyroid gland of a 52-year-old woman. The removed tumor had lymph follicle formation with a germinal center. This lymphatic tissue showed papillary and island-like growth; the growths were surrounded by atypical epithelium showing nuclear features of papillary carcinoma. The atypical epithelium had ground-glass nuclei with nuclear grooves, clearly indicating intranuclear cytoplasmic inclusion bodies. No chronic thyroiditis was observed in the background of the patient. Parts of the metastatic lymph nodes had cells with an eosinophilic cytoplasm, clearly showing an intratumor lymph follicle formation, as in the primary lesion. This is a rare case of thyroid papillary carcinoma similar to Warthin's tumor of the salivary gland. Here we present this case, with a review of previously published reports.

Warthin-like papillary carcinoma of the thyroid

BACKGROUND

Warthin-like papillary carcinoma of thyroid is characterized by distinct papillary formations lined by tumor cells with oncocytic cytoplasm, nuclear features of papillary carcinoma, and brisk lymphoplasmacytic infiltrates in the papillary stalks. This tumor derives its name from its close resemblance to Warthin tumor of major salivary glands.

DESIGN

The clinicopathologic features of 17 patients with Warthin-like papillary carcinoma were studied.

RESULTS

Fifteen tumors occurred in women and 2 arose in men (age range, 23-63 years). The lesions ranged in size from 3 mm to 2.5 cm. Fine-needle aspiration biopsies were performed in 7 cases; 4 were diagnosed as papillary carcinoma, 2 as consistent with lymphocytic thyroiditis, and 1 as atypical cells. All 17 tumors were confined to the thyroid; 6 showed prominent cyst formation and the remaining tumors were solid. In each case, the tumor arose in a background of lymphocytic thyroiditis. Nodal metastases were identified in 3 cases; however, none showed distant metastases. In 7 cases, foci of papillary microcarcinoma and follicular variant of papillary carcinoma were found in other areas of the thyroid.

CONCLUSIONS

Warthin-like tumors can be mistaken for benign lymphoepithelial lesions of the thyroid, Hürthle cell carcinoma, and tall cell variant of papillary carcinoma in both fine-needle aspiration and histology specimens. Follow-up information on the previously reported cases has suggested that these tumors behave similarly to usual papillary carcinoma. The extensive lymphocytic infiltration in these tumors and their association with chronic lymphocytic thyroiditis may suggest a role for immunological mechanisms in the pathogenesis of thyroid tumors.