Anaplastic Transformation of Papillary Thyroid Cancer in the Retroperitoneum

Figure 2

Microscopic examination of the retroperitoneal mass. There were sheets of undifferentiated cells with no papillary architecture seen ((a) 100x). The malignant cells had rhabdoid features with abundant granular eosinophilic cytoplasm, eccentric, vesicular nuclei, and prominent nucleoli. Mitoses were readily identified ((b) 400x).

(a)

(b)