A 71-Year-Old Woman With NTRK Gene Fusion Thyroid Cancer


Jochen H. Lorch, MD, MS: I would like to present a case today of a 71-year-old woman who presented with a painless ball on her neck. She otherwise has a history of hypercholesterolemia, which is well controlled medically. On examination, there is a palpable, nontender, solitary left-to-the-midline neck mass, otherwise unremarkable. The clinical work-up and initial treatment, including laboratory tests, including TSH [thyrotropin] and thyroid globulin antibodies, all of those were normal. An ultrasound of the neck was then performed, which showed a 3.8-cm suspicious mass arising from the left thyroid lobe, and 4 suspicious submandibular lymph nodes, the largest one was 2.2 cm in size. She then had an ultrasound-guided fine needle aspiration, and that confirmed papillary thyroid cancer. A CT scan of the chest, abdomen, and pelvis showed no evidence of distant metastatic disease.

The patient then underwent a total thyroidectomy, with a central compartment neck dissection and left selective neck dissection, which showed a 3.8-cm papillary thyroid cancer rising from the left lobe of the thyroid, with 2 out of 7 positive central compartment lymph nodes, with tumor foci up to 1.3 cm in diameter. There was no external extension, and the stage was thus T2N1M0. She also had a good performance status, which was felt to be a 0.

After this, she underwent treatment with radioactive iodine and received 150 mCi. The whole body scan showed uptake in the neck only, consistent with thyroid remnant, and she was then continued on levothyroxine as is standard of care.

At follow-up at 2 months, her TSH was adequately suppressed at 0.2 mU/L, and thyroglobulin was still elevated at 26 ng/mL. The patient, since she also had some headaches, had an MRI of the brain, which actually revealed multiple small lesions. She then underwent biomarker testing through next-generation sequencing, which revealed an NTRK fusion. The panel was negative for RET mutations, BRAF, NRAS, and KRAS. Treatment with larotrectinib, 100 mg orally twice a day, was initiated.

Transcript edited for clarity.

Case: A 71-Year-Old Woman With Thyroid NTRK Gene Fusion Cancer

Initial Presentation

  • A 71-year-old woman presents with a painless “ball on his neck”
  • PMH: hypercholesterolemia, medically controlled
  • PE: palpable, non-tender solitary left-of-the midline neck mass; otherwise unremarkable

Clinical Workup and Initial Treatment

  • Labs: including TSH, anti-Tg antibodies WNL
  • Ultrasound of the neck revealed a 3.8 cm suspicious mass arising from the left thyroid; 4 suspicious submandibular lymph nodes, largest 2.2 cm in size
  • Ultrasound-guided FNAB of the thyroid mass and the largest lymph node confirmed undifferentiated papillary thyroid carcinoma
  • Chest/abdominal/pelvic CT showed no evidence of distant metastases
  • Patient underwent total thyroidectomy with therapeutic central compartment and left selective neck dissection
    • Pathology: 3.8 cm undifferentiated papillary thyroid cancer arising in left lobe of thyroid, 2 of 7 positive central compartment lymph nodes, largest 1.3 cm, no extra nodal extension
  • StageT2N1M1; ECOG PS 0

Follow-Up and Additional Treatment

  • She was treated with radioactive iodine 150 millicuries
    • Whole body scan showed uptake in neck only consistent with thyroid remnant
    • Added levothyroxine to regimen
  • Follow-up at 2 months TSH 0.2 mU/L; thyroglobulin 26 ng/mL
    • MRI of the brain revealed multiple small lesions
  • Biomarkers testing:NTRK fusion+, RET-, BRAF-, NRAS-,KRAS-
  • Initiated treatment with larotrectinib 100 mg PO BID
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