system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 75-year-old woman comes to the physician because of a 3-month history of involuntary weight loss and a painless lump on her neck. Physical examination shows a firm, irregular swelling on the right side of the neck. Ultrasonography of the thyroid gland shows a 2-cm nodule with irregular margins and microcalcifications in the right thyroid lobe. A biopsy of the thyroid nodule is performed. Which of the following changes would be most consistent with anaplasia?
assistant
Negative staining of tumor cells for thyroglobulin