Category: Thyroid

Monitor: 15

15 - A RARE CASE OF AGGRESSIVE FOLLICULAR VARIANT PAPILLARY THYROID CARCINOMA WITH NRAS MUTATION

Friday, Apr 26
11:00 AM – 11:30 AM

Objective :

We present a case with a lumbar spine (LS) mass found during evaluation of lower back pain. Further assessment revealed metastatic follicular variant papillary thyroid carcinoma (FVPTC) with NRAS mutation.


Methods :

NA


Results :

A 61 year old male with lower back pain presented with worsening lumbar pain. MRI demonstrated an epidural mass at spinal levels L2-L4. CT Chest/Abdomen/Pelvis redemonstrated this 8.4x4.9x6.0cm mass at the L3 pedicle/left paraspinal musculature effacing the spinal canal. An enlarged left thyroid lobe was noted with multiple nodules deviating the trachea. The patient underwent L2-L4 laminectomy and partial tumor resection with pathology consistent with metastatic thyroid carcinoma. The largest tumor fragment measured 4x3cm (Positive TTF-1, CK7, and thyroglobulin). Fine needle aspiration (FNA) of a hypoechoic calcified 1.7cm left thyroid nodule was suspicious for follicular neoplasm on cytology and molecular testing with Thyroseq V2 revealed NRAS mutation. Subsequently, the patient underwent external beam ration therapy to the LS. He then underwent total thyroidectomy which demonstrated a 2.0cm FVPTC, which was encapsulated and invasive within the left thyroid lobe with at least 6 foci of capsular transgression, and more than 4 foci of lymphovascular invasion. Molecular testing revealed NRAS mutation on both thyroid and spinal tumor. Four months after his lumbar surgery, a repeat MRI of the LS showed persistent disease with enlargement of the epidural mass to 8.1x7.9x5.8 cm with severe central canal stenosis. He was started on high dose dexamethasone in preparation of treatment with I-131. A pre-treatment  I-131 whole body dosimetry scan revealed uptake in the L1-L3 vertebral body, remnant thyroid tissue.  He received 202 mCi of I-131 and post I-131 MRI showed significant decrease in size of the dominant lumbar expansile lesion to 4.4x5.6x5cm with significant improvement. However, the patient developed an ischemic stroke, which was complicated by brainstem herniation, and deceased.


Discussion :

The pathology and tumor biology of this FVPTC appeared seemingly indolent for such an aggressive presentation of metastatic FVPTC. Despite that NRAS mutations are known to be less aggressive, the clinical course of the cancer presented more like a  dedifferentiated thyroid cancer. This rare case demonstrates that while molecular testing has greatly advanced our approach towards managing thyroid cancer, observing the natural course of the tumor and using strong clinical acumen is central.


Conclusion :

We have presented an aggressive FVPTC with NRAS Mutation with LS metastasis and emphasized on the importance of using clinical judgment in conjunction with molecular testing. 

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Esra Kalkan

Fellow
Icahn School fo Medicine at Mount Sinai Beth Israel

Clinical Fellow

Michael Via

Attending Physician
Icahn School of Medicine at Mount Sinai Beth Israel

PD at Icahn School of Medicine at Mount Sinai Beth Israel Endocrinology Program.

Sophia Hu

Attending Physician
Icahn School of Medicine at Mount Sinai Beth Israel

Attending Physician at Icahn School of Medicine at Mount Sinai Beth Israel Endocrinology Department

Pinar Smith

Clare H. Bryce