Role of Immunohistology in the Study of Cellular Immunotypes and in Differential Diagnosis

1963, Saltzstein’ suggested pathologic criteria for separating benign inflammatory tumors (pseudolymphomas) from lymphomas of the lung. The criteria for the diagnosis of pseudolymphoma were the presence of a mixed cellular infiltrate (mature lymphocytes predominating), the presence of germinal centers, and regional lymph nodes free of lymphoma. In 1974, Reich et al,’ described five cases of pseudolymphoma, two with solitary masses and three with diffuse interstitial infiltrates, and concluded on the basis of follow-up studies, that unequivocal differentiation of lymphocytic lymphoma vs pseudolymphoma on the basis of light microscopy could not be made. Marchevsky et al3 have also concluded pathologic criteria do not allow prediction of recurrence or progression of disease in patients with lymphoid nod