Thyroid Research and Practice

CASE REPORT
Year
: 2015  |  Volume : 12  |  Issue : 2  |  Page : 80--82

Cytomorphology of Warthin-like variant of papillary thyroid carcinoma


Flora D Lobo1, Murali Nirupama1, Radha R Pai1, Anand U Kini2,  
1 Department of Pathology, Kasturba Medical College, Mangalore, Karnataka, India
2 Department of Surgery, Kasturba Medical College, Mangalore, Karnataka, India

Correspondence Address:
Murali Nirupama
Department of Pathology, Kasturba Medical College, Affiliated to Manipal University, Manipal 576 104, Karnataka
India

Abstract

Warthin-like variant of papillary thyroid carcinoma (PTC) is one of the several variants of papillary thyroid cancer. A 36-year-old female came with history of thyroid swelling. Ultra sound showed a solid nodule in the right lobe. Thyroid profile was within normal limits. Fine needle aspiration cytology (FNAC) revealed papillary carcinoma in a background of lymphocytic thyroiditis. Patient underwent thyroidectomy. Histopathology proved it to be Warthin-like variant of PTC with nodal metastasis. This uncommon variant behaves in an indolent fashion. However, our case is unique as it showed nodal metastasis. Cytodiagnosis is challenging with rare reports of cases diagnosed on FNAC. Herein we document cytomorphology of this uncommon variant reported at our institution.



How to cite this article:
Lobo FD, Nirupama M, Pai RR, Kini AU. Cytomorphology of Warthin-like variant of papillary thyroid carcinoma .Thyroid Res Pract 2015;12:80-82


How to cite this URL:
Lobo FD, Nirupama M, Pai RR, Kini AU. Cytomorphology of Warthin-like variant of papillary thyroid carcinoma . Thyroid Res Pract [serial online] 2015 [cited 2021 Jan 23 ];12:80-82
Available from: https://www.thetrp.net/text.asp?2015/12/2/80/153349


Full Text

 INTRODUCTION



Papillary carcinoma is the most common primary malignancy (80%) of the thyroid gland. [1],[2],[3],[4],[5],[6],[7] Known for its disguise in morphology; it is still recognized based on its architecture, growth pattern, cellular, and stromal features. Fine needle aspiration cytology (FNAC) is highly accurate in diagnosing papillary carcinoma. [1],[6] Warthin-like variant of papillary carcinoma poses diagnostic challenge.

 CASE REPORT



This patient was a 36-year-old female who presented with a thyroid swelling, noticed incidentally during a general health checkup. She had no relevant history of thyroid or related illness. Ultrasound revealed solid nodule in the right lobe, the other lobe was normal. Thyroid profile was within normal limits. FNA elsewhere was diagnosed as lymphocytic thyroiditis. On review in our institution, a diagnosis of papillary carcinoma in a background of thyroiditis was made. She underwent total thyroidectomy with neck dissection.

Pathologic findings

Cytological findings: Cellular smears with dual population composed of cells arranged in papillary tissue fragments, three-dimensional groups, clusters, and dispersed singly with admixed lymphocytes. Cells had moderate eosinophilic dense cytoplasm with round to oval nuclei. Nuclei were vesicular with few longitudinal grooves and had intranuclear cytoplasmic inclusions. Some of the cells had squamoid appearance, while few others were comparatively tall. Admixed were seen dispersed polymorphous population of lymphocytes [Figure 1]a and b]. Occasional multinucleate giant cells (non-phagocytic) were seen. With these features differential diagnosis of papillary carcinoma in lymphocytic thyroiditis was made. Patient underwent total thyroidectomy with lymph node dissection.

Gross pathology

Right lobe of thyroid gland measured 7.5 × 3.5 × 3 cm, and left lobe measured 4.5 × 3.5 × 3 cm. Outer surface showed attached fibro-fatty tissue measuring 8 × 3 cm. The entire gland was encapsulated except on posterior aspect of right lobe. Cut surface of right lobe showed a  circumscribed nodule measuring 2 cm in diameter, with a grey-white granular surface. Eleven lymph nodes in fibro-fatty tissue and two separately sent lymph nodes were identified. The resected surface was painted and sectioned.

Microscopy

Sections revealed thyroid gland with a tumor comprising of arborizing papillary fronds and follicles lined by tall, Hurthle cells with vesicular, to hyperchromatic large round nuclei [Figure 2]c. Cells had abundant oncocytic cytoplasm with fine granularity. Numerous intranuclear inclusions were seen. Psammoma bodies were absent. Multinucleated giant cells were seen overlying the papillae and in the lumen [Figure 2]b. The papillary stalks were distended with lymphoplasmacytic infiltrate and lymphoid follicles with germinal centers [Figure 2]a. The tumor had evoked a fibrous response and was seen infiltrating posteriorly up to the capsule. Anteriorly the excised margin was free of tumor. Two separately sent pretracheal lymph nodes showed metastatic deposits [Figure 2]d.{Figure 1}{Figure 2}

Histopathological diagnosis of Warthin-like variant of papillary thyroid carcinoma (PTC) was made.

 DISCUSSION



The Warthin-like variant of PTC accounts for only 9% of all PTC [2] and are more common in middle-aged women (33-55 years). [3] In the above case it was a solid nodule while it can also present as cystic lesion. [8] In a study of 17 tumors; 6 showed prominent cystic changes, while solid nodule was seen in majority of cases. [3] Fine needle aspiration showed follicular cells displaying the feature of papillary carcinoma in a lymphocytic background. This was first observed by Apel et al., and named so as it resembled papillary cystadenoma lymphomatosum (Warthin tumor) of salivary gland. [3],[4],[7],[9]

In our case, with initial diagnosis of lymphocytic thyroiditis in a different lab, on review showed the presence of syncytium of tumor cells with oncocytic cytoplasm and nuclear features of papillary carcinoma in a background of lymphoplasmacytic cells. [3] Fine nuclear chromatin, nuclear grooves, and intranuclear inclusions were characteristically present.

Differential diagnoses include usual PTC with reactive lymphocytes, PTC in Hashimoto's thyroiditis, Warthin-like variant, and tall cell variants of papillary carcinoma.

Usual papillary carcinoma can be diagnosed by minimal cytological criteria. [6],[8],[9],[10],[11] Diagnostic accuracy improves proportionally with adequacy of the samples. The minimal criteria for the diagnosis of papillary carcinoma includes a syncytial pattern of tissue fragment of follicular epithelium with typical nuclear morphology of dusty chromatin, grooves, macronucleoli, and intranuclear cytoplasmic inclusions exceeding 10% of the nuclear surface area. [1]

Papillary carcinoma and papillary hyperplasia in a background of Hashimoto's thyroiditis is difficult and challenging. As Hashimoto's thyroidoitis can show nodular presentation and when associated with papillary hyperplasia it may show problems in diagnosis. But when nuclear criteria are followed, papillary hyperplasia is excluded.

Cytological features of Warthin-like variant versus tall cell variant are not distinct. Usually the tall cells have abundant cytoplasm on cytology and are easily mistaken for Hurthle cells, as tall cells tend to become flat especially when spread with pressure. [2]

Usual papillary carcinoma thyroid with reactive lymphocytic infiltrate, papillary carcinoma in a background of Hashimoto's thyroiditis and Warthin-like variant of PTC are close mimickers and pose diagnostic challenge on cytology. However, it is crucial to identify the features of PTC despite dense lymphocytic background. In the present case diagnosis was confirmed histopathologically and unlike most cases documented, there was lymph node metastasis indicating a possible aggressive tumor.

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