Focally ulcerated mucosal fragments infiltrated by malignant tumor composed of sheets of dissociated undifferentiated large and intermediate size malignant cells. Anaplasia and mitoses are marked.
CD20 shows diffuse positive staining.
CD3 stains many reactive cells.
CK is negative.
S-100 protein is negative.
CD56 is negative.
Ki-67 LI is about 30% in hot spots.
Referred paraffin block for immunostaining of biopsy from Rt. Oropharyngeal mass involving Rt. Tonsil and base of tongue.
One referred paraffin block & one HX&E stained slide coded 3689-26. Sections immunostained for CD20, CD3, CD56, S-100, Synaptophysin, S-100 and Ki-67.
Rt. Oropharyngeal mass, biopsy and immunostaining, referred paraffin bloc for review: