1Department of Hospital Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea
2Department of Pathology, Seoul National University College of Medicine, Seoul, Korea
3Department of Epidemiology and Preventive Medicine, Graduate School of Public Health, Seoul National University, Seoul, Korea
4Department of Pathology, University of Ulsan College of Medicine, Seoul, Korea
5Department of Pathology, Ajou University School of Medicine, Suwon, Korea
6Department of Pathology, Daerim Saint Mary’s Hospital, Seoul, Korea
7Department of Pathology, Hallym University College of Medicine, Seoul, Korea
© 2015 The Korean Society of Pathologists/The Korean Society for Cytopathology
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I. Nondiagnostic or unsatisfactory |
• Normal thyroid tissue only |
• Extrathyroid tissue only (e.g., skeletal muscle, mature adipose tissue) |
• A virtually acellular specimen |
• Acellular/paucicellular fibrotic nodule |
• Blood clot only |
• Other |
II. Benign lesion |
• Benign follicular nodule or consistent with a benign follicular nodule |
• Hashimoto's thyroiditis |
• Granulomatous (subacute) thyroiditis |
• Nonthyroidal lesion (e.g., parathyroid lesions, benign neurogenic tumors, benign lymph node) |
• Other |
III. Indeterminate lesion |
IIIA. Indeterminate follicular lesion with nuclear atypia |
• Follicular proliferative lesions with focal nuclear atypia |
• Follicular proliferative lesions with equivocal or questionable nuclear atypia |
• Atypical follicular cells embedded in a fibrotic stroma |
IIIB. Indeterminate follicular lesion with architectural atypia |
• Microfollicular proliferative lesion lacking a fibrous capsule or the adjacent nonlesional tissue in the specimen |
• Solid or trabecular follicular lesion lacking a fibrous capsule or the adjacent nonlesional tissue in the specimen |
• Macrofollicular proliferative lesion with a fibrous capsule |
• Hürthle cell proliferative lesion lacking a fibrous capsule or the adjacent nonlesional tissue in the specimen |
IIIC. Other indeterminate lesions |
IV. Follicular neoplasm or suspicious for a follicular neoplasm |
• Microfollicular proliferative lesion with a fibrous capsule |
• Mixed microfollicular and normofollicular proliferative lesion with a fibrous capsule |
• Solid/trabecular follicular proliferative lesion with a fibrous capsule |
• Hürthle cell proliferative lesion with a fibrous capsule |
• Follicular neoplasm with focal nuclear atypia |
V. Suspicious for malignancy |
• Suspicious for papillary carcinoma, medullary carcinoma, poorly differentiated carcinoma, metastatic carcinoma, lymphoma, etc. |
VI. Malignant |
• Papillary thyroid carcinoma, poorly differentiated carcinoma, undifferentiated (anaplastic carcinoma), medullary thyroid carcinoma, lymphoma, metastatic carcinoma, etc. |
Comments |
1. The core needle biopsy provides an accurate diagnosis in most cases; however, it may miss some cancers or sometimes may be inconclusive. |
2. Definitive therapeutic surgery (i.e., a total thyroidectomy) should not be undertaken as a result of a category III, IV, or V core needle biopsy diagnosis. |
3. The management of a thyroid lesion must be based on a multidisciplinary approach. |