Anaplastic carcinoma of the thyroid with sclerohyaline nodules.

Sclerohyaline nodules, resembling deposits of amyloid, were noted in 3 cases of anaplastic thyroid carcinoma (ATC). All 3 patients were elderly, and 2 had good outcomes. Histologically, the nodules were dispersed throughout typical areas of ATC and formed the dominant histologic feature in these areas. The nodules were paucicellular and surrounded by both ATC and chronic inflammatory cells, including prominent numbers of eosinophils. Other areas of the stroma had a more keloidal appearance with minor myxoid foci. The hyaline nodules were negative for calcitonin, amyloid A, type IV collagen, and laminin. We regard these nodules as a response of the extracellular matrix to infiltrating ATC.