This patient in their 30s described a neck swelling for a number of years. They were of middle eastern extraction and the differential consisted of TB, papillary thyroid cancer metastases and SCC metastases (less likely given the age). Similar lesions in the ipsilateral lobe of the thyroid (see here) suggested thyroid origin, which was confirmed on histology.

Papillary cancer of the thyroid is the most common malignancy of the gland, accounting for approximately 60 – 80% of thyroid neoplasms. It has a tendency to metastasise early to local lymph nodes (50% at presentation c.f. 10% for follicular thyroid cancer), usually to the ipsilateral jugular chain (~90%) and is usually confined to the mid and lower lymph node stations, level 3 and 4 (~75%). In approximately 15% of patients lymph node metastases are the first presentation. Distal haematogenous dissemination is less common than with follicular cancer, seen only in 5 – 10% of patients at presentation.

The lymph nodes tend to have cystic components and usually thick nodular walls with septae (~35%, ~40% and ~60% respectively. Purely cystic nodes are uncommon and more frequent in young patients. Calcification may be seen occasionally as in this case.
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References:
1. Amirsys Statdx.com
2. P. Wunderbaldinger, et al. “Cystic Lymph Node Metastases in Papillary Thyroid Carcinoma” AJR 2002; 178:693-697

Credit: Dr Frank Gaillard