Sections show diffuse infiltration by a highly cellular malignant neoplasm composed predominantly of large atypical cells arranged in sheets and diffuse aggregates. The tumor cells exhibit moderate to abundant cytoplasm and markedly pleomorphic nuclei with irregular contours, vesicular chromatin, and variably prominent nucleoli. Mitotic activity is increased, including atypical mitotic figures. A variable admixture of small reactive inflammatory cells is present in the background.
Immunohistochemical studies demonstrate that the tumor cells are positive for CD3, and CD30, and negative for CK, CD20, ALK, TdT, CD15, and CD138. The Ki-67 labeling index is about 70%.
Left fronto-parietal skull bone lesion.
Two soft tissue with bone fragments measured 6.5x5x2.5 cm and 3x2.5x1.5 cm, totally embedded.
Lt. Fronto-parietal skull bone lesion: