A microscopic feature of seminoma include all of the following except -
Microscopic features of Seminoma

Sheets of uniform (monomorphic) cells, i.e., seminoma cells,
Sheets are divided into poorly demarcated lobules by delicate septa of fibrous tissue.
Septa is infiltrated with T- lymphocytes.
Sometimes prominent granuloma

Seminoma cell has the following features

Large and round to polyhedral.                            
Distinct cell membrane                                            
Clear or watery appearing cytoplasm.                
A large central nucleus with one or two prominent nuclei.
Cytoplasm contains glycogen.
 Placental alkaline phosphatase and keratin positive.
Gland formation
Lymphocytic infiltration
Monomorphic cells
Destruction of seminiferous tubules