This patient has been treated with the rectal tumor resection, hyperthermic intraperitoneal chemotherapy (HIPEC), and chemotherapy for the colorectal disease. FNAs of the neck have demonstrated papillary thyroid carcinoma.

Further thyroidectomy and neck dissection has been performed: 

MICROSCOPIC DESCRIPTION: 1-3. Sections show unremarkable parathyroid tissue admixed with adipocytes. There are no atypical features. 4. The tumor is a conventional papillary thyroid carcinoma comprising papillae and cords of columnar cells within fibrotic stroma. Tumor cells have crowded, overlapping nuclei with irregular nuclear borders, grooves and chromatin clearing. Lymphovascular invasion is present. Perineural invasion is not seen. Tumor extends into surrounding fat but there is no invasion of skeletal muscle. Tumor is within 0.5 mm of the posterior margin. A 1 mm focus of papillary carcinoma is also seen in the left lobe away from the main tumor focus. The remaining thyroid is unremarkable. A small area of normal parathyroid tissue is seen on the right side. 5. Sections show seven of ten lymph nodes with metastatic papillary carcinoma, 1-7 mm in size. Extranodal extension is not present. 6. Sections show one of sixteen lymph nodes with metastatic papillary carcinoma, 13 mm in size. Extranodal extension is not present. 7. Sections show one of six lymph nodes with metastatic papillary carcinoma, 10 mm in size. Extranodal extension is not present. 8. Sections show six of nine lymph nodes with metastatic papillary carcinoma, 2-13 mm in size. Extranodal extension is not present. 9. Sections show six lymph nodes with no evidence of malignancy.

DIAGNOSIS: Papillary thyroid carcinoma - Arising in left mide lobe - 15 mm maximum dimension - Lymphovascular invasion present - Narrowly clear of margins - No invasion of strap muscles - Separate 1 mm focus within left lobe, clear of margins - 15 of 47 lymph nodes with metastatic carcinoma, 1-13 mm in size, no extranodal spread; (central 7/10, 2A 1/16, 3 1/6, 4 6/9, 5 0/6). Small amount of normal parathyroid tissue.