Anaplastic Thyroid Carcinoma

Case presentation

Timeline

• 2022-08-15 FNA: ATC vs PDTC, but need more tissue for confirmation and ancillary testing
• 2022-08-19 Core bx:
  • Gross: Sections show an infiltrative malignant neoplasm composed primarily of plump, epithelioid and spindle cells with pleomorphic nuclei, mitotic activity, and background acute and chronic inflammation. In this tumor component, there is no appreciable nesting, squamous, glandular, or other differentiation. There is, however, a focus of a more well-differentiated neoplasm in nests, cords, and small follicles, a few with colloid, which is morphologically consistent with a follicular neoplasm.
  • IHC: +PAX-8 (nested foci and spindled component strong and extensive) and TTF-1 (nested foci strong and extensive and spindled component more focal). The nested foci are strongly and extensively positive for cytokeratins AE1/AE3 and 8/18 while the spindled component is negative for both cytokeratins.
• 2022-08-21 BRAF PCR: + for c.1799T>A (p. V600E)