Endocrine · Year 2 · from Endocrine

Case 1: Papillary Thyroid Carcinoma

Patient Demographics

  • Age: 35 years
  • Sex: Female
  • Occupation: Pediatric nurse

Chief Complaint

"I found a lump in my neck while putting on a necklace."

History of Present Illness

A 35-year-old woman noticed a painless lump in the right side of her neck 2 weeks ago while adjusting her necklace. She has no symptoms of hyperthyroidism or hypothyroidism. She denies dysphagia, hoarseness, or neck pain. She has no history of head or neck radiation. She reports that her aunt had thyroid cancer in her 40s. The lump has not changed in size since she first noticed it.

Physical Examination

  • Vital Signs: BP 118/74 mmHg, HR 72 bpm
  • General: Healthy-appearing woman in no distress
  • Neck:
  • 1.5 cm firm, non-tender nodule in right thyroid lobe
  • Nodule moves with swallowing
  • Fixed to underlying tissue
  • Left thyroid lobe normal
  • Single 1 cm firm, non-tender lymph node in right level VI (central) compartment
  • Voice: Normal

Workup

  • Laboratory Studies:
  • TSH: 1.8 mIU/L (normal)
  • Calcitonin: Normal (rules out medullary thyroid cancer)
  • Ultrasound Thyroid:
  • Right lobe: 1.6 cm hypoechoic nodule with irregular margins, microcalcifications, and taller-than-wide shape (highly suspicious features)
  • Left lobe: Normal
  • Right central neck: 1.2 cm lymph node with loss of fatty hilum, microcalcifications
  • TI-RADS 5 (highly suspicious)
  • Fine Needle Aspiration (FNA):
  • Thyroid nodule: Bethesda VI - Malignant (papillary thyroid carcinoma)
  • Lymph node: Positive for metastatic papillary thyroid carcinoma

Diagnosis

Papillary thyroid carcinoma with central compartment lymph node metastasis

Treatment

  1. Surgical resection:
  • Total thyroidectomy (nodule >1 cm with confirmed malignancy)
  • Central neck lymph node dissection (confirmed metastasis)
  • Consider lateral neck dissection if suspicious lateral nodes
  1. Post-operative:
  • Levothyroxine replacement with TSH suppression (goal TSH 0.1-0.5 mIU/L for intermediate risk)
  • Radioactive iodine (I-131) ablation for intermediate/high-risk patients
  1. Monitoring:
  • Serum thyroglobulin (tumor marker) - should be undetectable after total thyroidectomy/RAI
  • Anti-thyroglobulin antibodies
  • Neck ultrasound every 6-12 months initially
  1. Prognosis: Excellent - >95% 10-year survival for papillary thyroid cancer

Clinical Pearl

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy (80-85% of cases). Ultrasound features that increase suspicion for malignancy include hypoechogenicity, microcalcifications (psammoma bodies), irregular margins, taller-than-wide shape, and extrathyroidal extension. The TI-RADS (Thyroid Imaging Reporting and Data System) standardizes nodule evaluation and FNA recommendations. While PTC frequently metastasizes to lymph nodes, this does not significantly worsen prognosis in most patients. Thyroglobulin serves as an excellent tumor marker after total thyroidectomy, as it should only be produced by thyroid tissue.

Clinical Image

Ultrasound image showing a hypoechoic thyroid nodule with irregular margins and microcalcifications, features suspicious for papillary thyroid carcinoma.

Image Source: Radiopaedia - "Papillary thyroid carcinoma" License: CC BY-NC-SA 3.0 URL: https://radiopaedia.org/cases/papillary-thyroid-carcinoma-2

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