Session: SAT 429-448-Thyroid Neoplasia & Case Reports
Poster Board SAT-442
Clinical Case: A 63-year-old male with a history of recurrent lung cancer, treated with lobectomy and chemotherapy, was noted to have a right lower pole thyroid nodule on follow up CT of chest, and referred to Endocrinology. He had no history of thyroid dysfunction, radiation exposure, and never felt any mass in his neck. Clinically, the nodule was firm on palpation and mobile on deglutition. Review of CT scans did not reveal any significant interval change in size of the thyroid nodule in 15 months. Thyroid US revealed a complex, predominantly hypo echoic lesion measuring 1.8 cm within the right lower pole, along with multiple similar lesions measuring up to 1cm in the mid and upper poles of the left thyroid lobe. An US-guided FNAB of the right lobe nodule was performed. As the cytology was suspicious for malignancy, the patient had resection of the right thyroid lobe. Surgical pathology confirmed metastaic adenosquamous lung carcinoma. A PET scan done later revealed no uptake. Oncology intends to follow without any further intervention at this time.
Cytology: Suspicious for malignancy without nuclear clearing, inclusions, or papillary architecture. Immunohistochemical staining was negative for p63, which was positive in the lung tumor.
Surgical pathology: Frozen section revealed squamoid lesion, favoring metastatic squamous cell carcinoma. The lesion showed cystic architecture with atypical squamoid cells lining the cystic spaces. These cells showed focal p63 positivity, but were negative for TTF-1 and CK5/6. Focal papillary architecture was noted; however, overt cytologic features of papillary thyroid carcinoma were not identified. Margins were negative for tumor. Second opinion from JPC was adenosquamous carcinoma involving adenomatoid nodule.
Conclusion: Though the thyroid gland can be a site of metastases, especially in a patient with a prior history of malignancy, this case is unusual as there was no significant interval change in size by CT in 15 months and the nodule was metabolically inactive by PET scan.
Nothing to Disclose: RCB, SY, RP, AB, SM, AL
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