[580] Oxyphilic Hypercellular Follicular Nodule (OHCFN) of the Thyroid: A 10 Year Experience

AL Patton, SP Gmitro, JA Brainard. Cleveland Clinic, Cleveland, OH

Background: The term oxyphilic hypercellular follicular nodule (OHCFN) is used in thyroid FNA to describe cellular aspirate samples comprised nearly exclusively of Hurthle cells. Associated surgical pathology diagnoses commonly include benign hyperplastic nodule in the setting of lymphocytic thyroiditis, as well as Hurthle cell adenoma or carcinoma. Prior authors have suggested an increased rate of neoplasms in this patient group when compared with cellular non-Hurthle follicular nodules. Recently, measurement of preoperative TSHR mRNA has proven helpful in identifying patients with thyroid malignancy. The goal of our study is to correlate FNA interpretation with surgical diagnosis and results of preoperative TSHR mRNA testing when available.
Design: The electronic pathology database was searched for thyroid FNA samples interpreted as OHCFN. These samples share in common a cellular Hurthle cell sample with minimal colloid with cells arranged in a predominantly microfollicular pattern. Surgical pathology diagnoses were collated. Preoperative TSHR mRNA elevation (>1.0 ng/ug) was assessed in a subset.
Results: 182 FNA's interpreted as OHCFN over a 10 year period were studied (138 female, 44 male, median age 55.5 years). Histologic follow-up was available for 137 cases (Table 1).

Follow-up histology of 137 surgical cases with the cytologic diagnosis "Oxyphilic Hypercellular Follicular Nodule"
Surgical DiagnosisNumberPercentage
Hurthle Cell Carcinoma2619
Papillary Thyroid Carcinoma96.6
Hurthle Cell Adenoma4331.4
Benign Thyroid Nodule5137.2
Chronic Lymphocytic Thyroiditis85.8

Of these, 36 pts had chronic lymphocytic thyroiditis, 24 non-neoplastic cases and 12 neoplasms. Preoperative TSHR mRNA was tested in 16 cases (Table 2).

Final histologic diagnosis of cases having preoperative TSHR mRNA evaluation (n=16)
Final Histologic Diagnosis# of patients having normal TSHR mRNA (<1.0 ng/ug)# of patients having elevated TSHR mRNA (>1.0 ng/ug)
Hurthle Cell Carcinoma3†2
Papillary Thryoid Carcinoma20
Hurthle Cell Adenoma4†0
Benign Thyroid Nodule32†
There was 1 case from each of these categories having an incidental microscopic papillary thryoid carcinoma.†

Conclusions: The majority of FNA's interpreted as OHCFN are neoplasms (59.6%) and nearly half of these are malignant . Chronic lymphocytic thyroiditis is identified in nearly one-third of patients. Elevated preoperative TSHR mRNA values did not correlate with histologic follow-up of malignancy in our study.
Category: Endocrine

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 43, Tuesday Afternoon


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