BRACHIAL PLEXOPATHY SECONDARY TO ANAPLASTIC THYROID CARCINOMA

Document Type

Conference Proceeding

Publication Date

7-17-2025

Publication Title

J Gen Intern Med

Keywords

C reactive protein, aged, anaplastic thyroid carcinoma, brachial plexus, brachial plexus neuropathy, breast cancer, cancer patient, case report, cervical spine, clinical article, colorectal cancer, complication, conference abstract, diagnosis, differentiated thyroid cancer, dysphagia, epidural space, female, flexible laryngoscopy, genetic screening, human, lung metastasis, MRI scanner, neck dissection, neck tumor, nuclear magnetic resonance imaging, paresthesia, radiotherapy, range of motion, shoulder pain, thyroid papillary carcinoma, thyroidectomy, total thyroidectomy, transverse process, weakness

Abstract

CASE: A 68-year-old female with past medical history of cervical, uterine, and colorectal cancer status post respective treatments was diagnosed with papillary thyroid cancer and underwent total thyroidectomy with left neck dissection in late 2023. Radio ablative iodine treatment was completed in early 2024. Five months following radio ablation, the patient presented to her primary physician with acute neck and left shoulder pain associated with numbness and weakness. Symptoms subsequently progressed to complete loss of range of motion of her left shoulder. CT neck revealed an ill-defined necrotic soft tissue mass in the left neck extending posteriorly into the anterior scalene, surrounding the common carotid almost to the bifurcation, and abutting the transverse processes of C5-C7 with cortical erosions. Lab work demonstrated elevated CRP (21.2 mg/dL) and ESR (65mm/Hr). Due to intermittent dysphagia, a flexible laryngoscopy was obtained which showed a medialized left arytenoid, likely from mass effect. MRI results revealed a large infiltrative left neck mass involving the left brachial plexus, neck musculature, and cervical vasculature. Osseous tumor infiltration of the cervical spine and epidural space, without mass effect on the spinal cord. Unfortunately, biopsy of the area revealed anaplastic thyroid carcinoma. Genetic testing revealed a BRAF mutation. Aligning with patient care goals, she transitioned to hospice care. IMPACT/DISCUSSION: Breast cancer, lymphoma, lung cancer, and head and neck tumors are the most common causes of neoplastic brachial plexopathy. This remains a rare complication of malignancy with only 0.43% of cancer patients being affected; Breast and lung metastasis make up 32% and 37% of these cases respectively. There is limited literature discussing brachial plexopathy secondary to papillary thyroid cancer and no current literature, to our knowledge, of anaplastic thyroid cancer-induced brachial plexopathy. This case highlights a rare cause of brachial plexopathy with a clinical presentation atypical for thyroid cancer. This emphasizes the need for clinicians to be aware of rare complications following thyroidectomy in conjunction with patient history. The transformation of papillary thyroid cancer to anaplastic thyroid cancer is rare, yet genetic mutations are hypothesized to be a main driver. Approximately 20% of patients diagnosed with anaplastic thyroid cancer have a history of well-differentiated thyroid cancer. This case highlights the significance of identifying potential genetic drivers of cancer as this can prime clinicians to stay alert to rare clinical presentations. CONCLUSION: Recognize rare causes of brachial plexopathy and symptom presentation Consider genetic drivers in patients with extensive cancer history.

Volume

40

First Page

S162

Last Page

S163

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