Molecular Profiling of 50 734 Bethesda III-VI Thyroid Nodules by ThyroSeq v3: Implications for Personalized Management.

CONTEXT: Comprehensive genomic analysis of thyroid nodules for multiple classes of molecular alterations detected in a large series of fine needle aspiration (FNA) samples has not been reported. OBJECTIVE: To determine the prevalence of clinically relevant molecular alterations in Bethesda categories III-VI (BCIII-VI) thyroid nodules. METHODS: This retrospective analysis of FNA samples, tested by ThyroSeq v3 using Genomic Classifier and Cancer Risk Classifier at UPMC Molecular and Genomic Pathology laboratory, analyzed the prevalence of diagnostic, prognostic, and targetable genetic alterations in a total of 50 734 BCIII-VI nodules from 48 225 patients. RESULTS: Among 50 734 informative FNA samples, 65.3% were test-negative, 33.9% positive, 0.2% positive for medullary carcinoma, and 0.6% positive for parathyroid. The benign call rate in BCIII-IV nodules was 68%. Among test-positive samples, 73.3% had mutations, 11.3% gene fusions, and 10.8% isolated copy number alterations. Comparing BCIII-IV nodules with BCV-VI nodules revealed a shift from predominantly RAS-like alterations to BRAF V600E-like alterations and fusions involving receptor tyrosine kinases (RTK). Using ThyroSeq Cancer Risk Classifier, a high-risk profile, which typically included TERT or TP53 mutations, was found in 6% of samples, more frequently BCV-VI. RNA-Seq confirmed ThyroSeq detection of novel RTK fusions in 98.9% of cases. CONCLUSION: In this series, 68% of BCIII-IV nodules were classified as negative by ThyroSeq, potentially preventing diagnostic surgery in this subset of patients. Specific genetic alterations were detected in most BCV-VI nodules, with a higher prevalence of BRAF and TERT mutations and targetable gene fusions compared to BCIII-IV nodules, offering prognostic and therapeutic information for patient management.

MOLECULAR PROFILE AND CLINICAL OUTCOMES IN DIFFERENTIATED THYROID CANCER PATIENTS PRESENTING WITH BONE METASTASIS.

Objective: Differentiated thyroid cancer patients uncommonly present with bone metastasis as the initial manifestation. Their molecular profile is largely unknown. The aim of this study was to evaluate the histopathology, molecular profiles, and response to radioactive iodine therapy in these patients. Methods: Eight patients presented with symptomatic bone metastasis from an unknown primary tumor. We identified these patients by performing a retrospective chart review. Pathology slides were reviewed and the molecular analysis of 112 thyroid cancer-related genes was performed on bone metastasis specimens using targeted next-generation sequencing. Results: These patients presented with long bone fractures, spinal cord compression, or intractable bone pain. Histopathologic analysis of the bone and thyroid tumor specimens revealed follicular variant of papillary carcinoma in 7 patients and tall cell variant papillary carcinoma in 1 patient. Primary tumor size ranged from 0.4 to 7.5 cm. All patients received high dose radioiodine therapy following thyroidectomy. Molecular analysis revealed telomerase reverse transcriptase (TERT) mutations in 7 (88%) tumors, 4 (50%) contained co-occurring TERT and RAS GTPase gene (RAS) mutations, 2 had isolated TERT mutations, and 1 had TERT and proto-oncogene B-Raf (BRAF) V600E mutations, respectively. Tumors carrying RAS, TERT, or a combination of these mutations were radioiodine-avid, with predictable tumor response and reduction in serum thyroglobulin levels. One patient with radioiodine-refractory disease harbored BRAF and TERT mutations. Conclusion: These results demonstrate that differentiated thyroid cancers presenting with bone metastasis independent of the primary tumor size have a high prevalence of TERT mutations, frequently coexisting with RAS mutations. This molecular signature may predict a favorable response to radioiodine therapy. Abbreviations: BRAF = proto-oncogene B-Raf; DNA = deoxyribonucleic acid; DTC = differentiated thyroid cancer; FV = follicular variant; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; RAS = Ras GTPase gene; TERT = telomerase reverse transcriptase; TG = thyroglobulin.

Utility of ultrasound-guided fine-needle aspiration of parathyroid adenomas for localization before minimally invasive parathyroidectomy.

OBJECTIVE: To determine the sensitivity and specificity of ultrasound (US)-guided fine-needle aspiration (FNA) and measurement of parathyroid hormone (PTH) in the aspirate (FNA/PTH) as a preoperative localization procedure. METHODS: The study group consisted of 34 consecutive patients with primary hyperparathyroidism. The FNA/PTH estimations in these patients were compared with those from 13 proven thyroid nodules. All patients underwent US study of the neck, which suggested the presence of a solitary adenoma in 30 patients and of hyperplasia in 2; no adenoma or hyperplasia could be visualized in 2 patients. Thirty-two patients underwent FNA/PTH, which yielded a mean PTH level of 22,060.0 +/- 6,653.0 pg/mL. This result was significantly different (P<0.001) from the mean PTH level in 13 thyroid nodules (9.0 +/- 1.0 pg/mL). RESULTS: On the basis of the FNA/PTH results, 28 patients with suspected adenomas underwent minimally invasive parathyroidectomy (MIP), and 2 patients are awaiting a surgical procedure. Of these 28 patients, 27 had more than a 50% decline in intraoperative PTH level after removal of the suspected adenoma, confirming surgical success. In 1 patient, multigland hyperplasia was discovered during the operation. The 2 study subjects with US findings of suspected hyperplasia underwent 4-gland surgical procedures. All patients treated surgically continued to have normal serum calcium levels 6 to 18 months postoperatively. CONCLUSION: Primary hyperparathyroidism is caused most commonly by a solitary adenoma and less commonly by multigland hyperplasia of the parathyroid glands. Surgical resection is the only curative therapy. MIP has become a frequently used strategy, but there are limitations to current preoperative localization techniques. We conclude that US-guided FNA is a useful technique that facilitates MIP, with a high degree of specificity (95%) and sensitivity (91%).