What is this dark structure in the center of this biopsy of a thyroid nodule?
A. Foreign body
B. Artifact
C. Psammoma body
D. Area of necrosis
E. Collection of fungal organisms
The structure at the center of this image is a psammoma body. Psammoma bodies are lamellated, calcific structures commonly seen in papillary carcinomas, such as this papillary carcinoma of the thyroid. The exact underlying cause or mechanism of psammoma bodies is not well understood. However, some studies have shown that in papillary thyroid carcinoma, psammoma bodies are associated with a lower disease-free survival and an overall worse prognosis.
-Kristine Krafts, MD, is an Assistant Professor of Pathology at the University of Minnesota School of Medicine and School of Dentistry and the founder of the educational website Pathology Student.
Lablogatory 
Nice way of spreading knowledge