Paula LaPolice, CT(ASCP), Baystate Medical Center, Springfield, MA, Ajay Shah, MD, FNA Clinic, Toledo, OH, Husain Saleh, MD, MBA, Detroit Medical Center, ...
Cytopathologic Interpretative Variation of Hashimoto's Thyroiditis: Synopsis of 1886 Responses from the ASCP NonGyn Assessment Program American Society for Clinical Pathology, NonGYN Assessment Committee
Stanley G. Eilers, MD, Mercy Medical Center, Cedar Rapids, IA, Michael S. Facik, MPA, CT(ASCP), University of Rochester Medical Center, Rochester, NY, Perkins Mukunyadzi, MD, Arkansas Pathology Associates, Little Rock AR, Paul E. Wakely, Jr, MD, The Ohio State University, Columbus, OH, Amy Wendel Spiczka MS, SCT, MP, HTL(ASCP)CM, Mayo Clinic, Scottsdale, AZ, Paula LaPolice, CT(ASCP), Baystate Medical Center, Springfield, MA, Ajay Shah, MD, FNA Clinic, Toledo, OH, Husain Saleh, MD, MBA, Detroit Medical Center, Detroit, MI, Umesh Kapur, MD, Loyola University Medical Center, Maywood, IL, Bryan Hunt, MD, Medical College of Wisconsin, Milwaukee, WI, Jennifer J. Clark, SCT(ASCP)CM, American Society for Clinical Pathology, Indianapolis, IN, Larry Lemon, CT(ASCP), American Society for Clinical Pathology, Indianapolis, IN
Introduction
Results
Hashimoto’s thyroiditis is a relatively common disease seen in thyroid cytopathology samples, therefore specimens from FNA and touch-prep samples of this entity were incorporated into the ASCP NonGYN Assessment program. The ASCP NonGYN Assessment Program is a glass-slide program developed with oversight from the ASCP NonGYN Assessment Committee. Each annual program is composed of FNA and NonGYN samples for a total of 20 patient cases, divided into 4 quarterly shipments of five cases. Laboratory and individual Peer-Comparison statistics for each case reviewed are provided to all participants post-event participation.
Experiment Design & Methods Performance data from 1886 total responses from seven cases of Hashimoto’s thyroiditis, circulating in the NonGYN Assessment program since 2007 were extracted and reviewed. 82.1% of participants chose the correct response of a Negative or Inflammatory process consistent with Hashimoto’s thyroiditis, while 12.1% classified the cases as Positive for Malignancy, the most common choice (6.4%) responding with malignant lymphoma. Less common, yet interesting, were malignant responses of 3.0% anaplastic carcinoma, and 2.3% Lesion of Uncertain Biologic Potential, follicular neoplasm. The remainder of responses included 0.3% non-neoplastic goiter; 1.4% Granulomatous thyroiditis; 0.7% metastatic melanoma; and 1.1% papillary carcinoma. 2.7% of the participants did not provide an interpretation response.
Diagnostic Differential Comparisons
Hashimoto’s Thyroiditis- a large, cohesive group of Hurthle cells. Hurthle cells display abundant granular cytoplasm with nuclei displaying prominent nucleoli. A background of benign, mature lymphocytes makes this pattern typical of Hashimoto's Thyroiditis. Compare below.
Hashimoto’s Thyroiditis- benign Hurthle cells arranged in cohesive groups, with rare single cells. Hurthle cells display abundant granular cytoplasm with low N/C ratios, and nuclei with nucleoli. Heterogeneous inflammatory component with mixture of small and large lymphocytes as well as plasma cells. Minimal, if any colloid in background. Compare below.
Hashimoto's Thyroiditis- characteristic population of lymphocytes and Hurthle cells. Hurthle cells represent damaged follicular cells. Singly dispersed lymphoid cells are most represented by small mature lymphocytes, among which are a few larger lymphocytes and histiocytes with more abundant cytoplasm and vesicular nuclei. Compare below.
Anaplastic Thyroid Carcinomalarge pleomorphic cells with dense cytoplasm, arranged in loose groups and singly. Large eccentrically placed nuclei with increased N/C ratios, coarse chromatin and irregular, multiple nuclei. Background may show tumor debris, but no colloid or other benign elements (including lymphocytes).
Follicular Neoplasmmonotonous pattern of follicular cells with a microfollicular or trabecular growth pattern. Nuclei may show a crowded or haphazard arrangement. Background of blood with minimal, if any colloid or cyst material. Abundant isolated cells with stripped nuclei may resemble lymphocytes.
Malignant Lymphoma- monomorphic population of medium to large abnormal lymphocytes, arranged singly in a dyscohesive pattern. Background contains lymphoglandular bodies, cellular debris and minimal, if any colloid or epithelial cells.
Conclusions In light of the 12.1% response rate for Positive for Malignancy, further microscopic evaluation of these cases was performed. The somewhat pleomorphic Hurthle cells with prominent nucleoli and the lack of colloid may have contributed to the anaplastic carcinoma responses, and to the follicular neoplasm responses. Responses of malignant lymphoma are self-evident, in light of the prominent lymphoid component in Hashimoto’s cases. Generally lymphomas have a more monotonous population with minimal, if any epithelial component. However, such a distinction may not always be possible based on the morphology alone, and immuostaining or flow cytometry might be necessary.
