Positive Cytology Findings and a Negative Histological Diagnosis of Papillary Thyroid Carcinoma in the Thyroid: Is It a False-Positive Cytology or a Disappearing Tumor?

Background: It infrequently occurs that cytologic diagnosis of papillary thyroid carcinoma (PTC) cannot be confirmed by histology after surgery. This phenomenon may be a false-positive cytology or a true disappearing tumor. Objectives: We evaluated patients who had consistent findings of PTC at fine needle aspiration cytology (FNAC) and no evidence of PTC in surgical specimens. Methods: Positive cytology findings and a negative histological diagnosis of PTC in the thyroid was defined as thyroid nodules with FNAC findings of PTC prior to surgery and no evidence of malignancy on histological examination of surgically removed thyroids. We retrospectively reviewed patients who underwent fine needle aspiration (FNA) and thyroidectomy in Asan Medical Center from 2004 to 2012. Results: Six patients were found who fit the definition of positive cytology findings and a negative histological diagnosis of PTC in the thyroid. The FNAC diagnosis of 6 patients was ‘malignancy' suggesting PTC according to the Bethesda system. All patients underwent thyroidectomy with central neck dissection. Three patients had reactive changes after FNA due to needle passage. Among these 3 patients, 2 had pathologically confirmed metastatic PTC in dissected lymph nodes. These 2 patients could be defined as true disappearing PTC in the thyroid after FNA. The remaining 3 patients had neither histologic alterations nor evidence of PTC in the thyroid and lymph nodes specimens. Conclusions: Both disappearing PTC and a false-positive result of FNAC should be considered in patients with positive cytology findings and a negative histological diagnosis of PTC in the thyroid.

[1]  I. Sugitani,et al.  Cytopathological review of patients that underwent thyroidectomies based on the diagnosis of papillary thyroid carcinoma by fine needle aspiration cytology but were later found to have benign tumors by histopathology , 2013, Surgery Today.

[2]  Eun-Kyung Kim,et al.  The diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy and the sonographic differences between benign and malignant thyroid nodules 3 cm or larger. , 2011, Thyroid : official journal of the American Thyroid Association.

[3]  J. Lew,et al.  Fine needle aspiration of the thyroid: correlation with final histopathology in a surgical series of 797 patients. , 2011, Journal of the American College of Surgeons.

[4]  C. Keller,et al.  Infarcted papillary thyroid cancer after fine needle aspiration biopsy , 2011, Endocrine.

[5]  E. Cibas,et al.  The Bethesda system for reporting thyroid cytopathology : definitions, criteria, and explanatory notes , 2010 .

[6]  S. Raab,et al.  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 , 2009 .

[7]  Juan Rosai,et al.  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 , 2008, Diagnostic cytopathology.

[8]  J. Rosai,et al.  Pitfalls in thyroid tumour pathology , 2006, Histopathology.

[9]  N. Kamel,et al.  Comparison of palpation-guided fine-needle aspiration biopsy to ultrasound-guided fine-needle aspiration biopsy in the evaluation of thyroid nodules. , 2006, Thyroid : official journal of the American Thyroid Association.

[10]  Z. Baloch,et al.  Cytologic and architectural mimics of papillary thyroid carcinoma. Diagnostic challenges in fine-needle aspiration and surgical pathology specimens. , 2006, American journal of clinical pathology.

[11]  Jeffrey E. Lee,et al.  Fine-needle aspiration of the thyroid and correlation with histopathology in a contemporary series of 240 patients. , 2003, American journal of surgery.

[12]  A. Gold.  Vanishing , 2003 .

[13]  A. Nassar,et al.  Histiocytic aggregates in benign nodular goiters mimicking cytologic features of papillary thyroid carcinoma (PTC) , 2003, Diagnostic cytopathology.

[14]  S. Diaz-Cano,et al.  Hashimoto's thyroiditis shares features with early papillary thyroid carcinoma. , 2002, Histopathology.

[15]  A. Pandit,et al.  Worrisome Histologic Alterations Following Fine Needle Aspiration of the Thyroid , 2001, Acta Cytologica.

[16]  D. Gümürdülü,et al.  Histologic alterations in the thyroid gland after fine‐needle aspiration , 1997, Diagnostic cytopathology.

[17]  S. Suster,et al.  Clear nuclear changes in Hashimoto's thyroiditis. A clinicopathologic study of 12 cases. , 1995, Annals of clinical and laboratory science.

[18]  D. Das,et al.  Role of nuclear grooves in the diagnosis of papillary thyroid carcinoma. A quantitative assessment on fine needle aspiration smears. , 1995, Acta cytologica.

[19]  M. Merino,et al.  Worrisome histologic alterations following fine-needle aspiration of the thyroid (WHAFFT). , 1994, Pathology annual.

[20]  P. Kragel,et al.  Multinodular goiter of the thyroid mimicking malignancy: Diagnostic pitfalls in fine‐needle aspiration biopsy , 1993, Diagnostic cytopathology.