Bongiovanni, Massimo

De Vito, Claudio

Pusztaszeri, Marc

Triponez, Frederic

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Macrofollicular Variant of Follicular Thyroid Carcinoma:A Case ReportClaudio De Vito & Massimo Bongiovanni &Frederic Triponez & Marc PusztaszeriPublished online: 7 April 2013# Springer Science+Business Media New York 2013Case ReportA 37-year-old female known for systemic lupus erythematosusunderwent a right thyroid lobectomy for a growing nodule inthe right lobe. A fine-needle aspiration biopsy (FNAB)performed 4 years before surgery reported a microfollicularproliferation. A second FNAB performed a few months beforesurgery revealed a benign lesion. The surgical specimen wasfixed in 4 % buffered formaldehyde. The entire nodule wassampled, with particular attention to the capsule, and embeddedin paraffin and corresponding sections were stained withhematoxylin and eosin for histological examination. Immuno-histochemistry using HBME1 and galectin-3 was performed.What is Your Diagnosis?The pathological diagnosis of the patient was follicularthyroid carcinoma, macrofollicular variant, which is minimallyinvasive, stage pT2 pNX.On gross section, the nodule measured 4×4×3.5 cm. Itwas encapsulated with a shiny colloidal appearance withoutcalcification (Fig. 1a). On histology, the nodule was encap-sulated, with variable capsule thickness. It was essentiallymacrofollicular (>200 μm) with a minor microfollicularcomponent (Fig. 1b). The cells were attenuated to cuboidalwith an eosinophilic cytoplasm and round hyperchromaticnuclei without any nuclear feature suspicious for papillarythyroid carcinoma (PTC) (Fig. 1c). No mitotic activity ornecrosis was found. Focal transcapsular invasion waspresent (Fig. 1b), but no vascular invasion was found.Immunohistochemistry showed focal but strong HBME-1staining essentially in the microfollicular areas (Fig. 1d)and absence of galectin-3 staining.CommentHere, we report the case of a minimally invasive follicularthyroid carcinoma (FTC) with a predominant macrofolliculargrowth pattern. Thyroid nodules with a macrofolliculararchitecture are considered for the most part as benignlesions and include nodular hyperplasia, adenomatousnodules, and some follicular adenomas. In contrast,FTCs are generally hypercellular and very few exhibitnormofollicular or macrofollicular appearances [1]. There-fore, the index of suspicion should be raised wheneverencountering a follicular neoplasm with a solid, trabecular, ormicrofollicular pattern of growth [1]. However, rare casesof thyroid malignant neoplasms with a macrofollicularpattern have been described such as the macrofollicularvariant of PTC [2] and the even rarer macrofollicularvariant of FTC [3]. Thus, lesions with a predominantmacrofollicular component should also be assessed for nuclearfeatures of PTC and for capsule and vascular invasion.Therefore, sampling the entire capsule is recommended.Correspondingly, FNAB provides essential informa-tion regarding architectural and cytology aspects of thethyroid nodules and plays a key role as a screening testfor thyroid follicular neoplasms [4, 5]. FTC classicallyshows microfollicular growth pattern and identificationof this component is the key feature in order to classify thesenodules as suspicious for a follicular neoplasm, even thoughC. De Vito :M. Pusztaszeri (*)Department of Clinical Pathology, Geneva University Hospital,1 rue Michel-Servet,1211 Geneva 14, Switzerlande-mail: marc.pusztaszeri@hcuge.chM. BongiovanniInstitute of Pathology, Locarno, SwitzerlandF. TriponezDepartment of Thoracic and Endocrine Surgery, GenevaUniversity Hospital, Geneva, SwitzerlandEndocr Pathol (2013) 24:167–168DOI 10.1007/s12022-013-9241-3the majority (>70%) of these nodules turn out to be benign onsurgical follow-up [4, 5]. Thus, cytological specimens ofmacrofollicular variant of FTC can be a pitfall and bemisinterpreted as benign due to the lack of microfollicles[5]. Therefore, they may account for an undetermined fractionof the false-negative FNAB cases. However, some of thesecases may fall into oblivion and never be detected as theirmalignant potential, if any, may never be apparent. Immuno-histochemistry (e.g., HBME-1, galectin-3) may support thediagnosis of malignancy for this rare variant of FTC withdeceivably bland architectural and cytological features.In conclusion, this case report illustrates a rare macro-follicular variant of FTC that can be misdiagnosed as abenign lesion, supports the need to thoroughly sample thenodule capsule, and assesses for vascular and capsular invasionalso in macrofollicular patterned thyroid nodules.References1. Rosai JCM, DeLellis R: Atlas of Tumor Pathology: Tumors of theThyroid Gland, series 3. Washington, Armed Forces Institute ofPathology, 1992.2. Albores-Saavedra J, Housini I, Vuitch F, SnyderWH3rd.Macrofollicularvariant of papillary thyroid carcinoma with minor insular component.Cancer 80:1110–1116, 1997.3. Bongiovanni M, Gremaud M, Moulin CS, Scheidegger C, Biton C,Clément S. Macrofollicular variant of follicular thyroid carcinoma: aclinical, cytologic, morphologic, and image analysis study of aunique case. Ann Diagn Pathol. 13:101–105, 2009.4. Cibas ES, Ali SZ. The Bethesda System For Reporting ThyroidCytopathology. Am J Clin Pathol. 132:658–665, 2009.5. Maruta J, Hashimoto H, Suehisa Y, Yamashita H, Noguchi S,Aratake Y, Ohno E, Kobayashi TK. Improving the diagnosticaccuracy of thyroid follicular neoplasms: cytological features infine-needle aspiration cytology. Diagn Cytopathol. 39:28–34,2011.Fig. 1 a Macroscopical aspectof the macrofollicular variant offollicular thyroid carcinoma. bThe tumor is encapsulated andshows a “mushroom-like” focusof transcapsular invasion intothe adjacent thyroidparenchyma. c The tumor iscomposed mainly ofmacrofollicles lined withcuboidal or attenuated cellswith bland nuclear features.d Tumor cells in the minormicrofollicular areas arestrongly immunopositivefor HBME-1168 Endocr Pathol (2013) 24:167–168

Macrofollicular Variant of Follicular Thyroid Carcinoma: A Case Report

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Macrofollicular Variant of Follicular Thyroid Carcinoma: A Case Report

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