Application of Immunohistochemical Stain for Granulocytic Sarcoma

ABSTRACT

Granulocytic sarcoma is a rare localized tumor composed of granulocytic precusor cells. Granu-locytic sarcoma occurs in a variety of clinical conditions and it is often misdiagnosed histologically. Differential diagnosis frorh lymphoma or nonhematopoietic malignancies such as undifferentiated carcinoma or sarcoma is difficult in the routing histologic examination. An evaluation of clinical and histopathologic features was done on 4 cases of granulocytic sarcoma which were diagnosed at Pusan Paik Hospital from 1988 to 1992. During the period, 282 cases of myelogenous leukemia were diagnosed. Immunohistochemical reaction for lysozyme, myelopero-xidase, leukocyte common antigen, epthelial membrane antigen and cytokeratin was assessed comparing to lymphoma and undifferentiated carcinoma. The histologic features of the granulocytic sarcoma revealed thin nuclear membrane, fine chromatin pattern and one or two small nucleoli. It also often involved the vascular wall and infiltrated the native structures without destruction. Immunohistochemical stain revealed that all(4 cases) of granulocytic sarcoma showed diffuse and strong positivity for myeloperoxidase, and partial but strong positivity for lysozyme. One case of granulocytic sarcoma was negative and 3 cases revealed focal positive reaction for LCA, and all 4 cases was negative for cytokeratin and EMA. In summary, careful observation under light microscopy with immunohistochemical stain for myeloperoxidase, lysozyme, and LCA is helpful in the differential diagnosis of granulocytic sarcoma from malignant lymphoma and cytokeratin and EMA is useful for differential diagnosis from undifferentiated carcinoma.