Concanavalin A-binding histiocytes in Hodgkin's disease. A predictor of early relapse.

Staining with Concanavalin agglutinin (Con A) reveals a far greater number of macrophage-histiocytes (M-H) in paraffin sections than any other staining method. With Con A staining, the shapes of stromal M-H are clearly visualized, thus enabling a study of their morphologic variations. Con A staining patterns were also unchanged in specimens left at room temperature for 24 to 28 hours before fixation. The appearance of Con A-binding histiocytes was studied in tumors, recurrent as well as original, of 18 patients with biopsy-proven early relapse (within 26 months of diagnosis), and compared with those of 26 patients who were in complete remission (lasting 48 months at the minimum). The early-relapse patients were diagnosed from 1977 through 1984, and all received intensive combination chemotherapy. The relapse-free patients were treated in various manners, and included six patients diagnosed in the 1960s who were treated with radiation alone. Three forms of Con A-binding histiocytes were easily recognized: medium-sized cells similar to those seen in reactive follicles, characterized by uniform nuclei and distinct, abundant cytoplasm (Type A); cells of varying size and shape with altered cytoplasm, rarefied and ragged with indistinct cell borders, or globular (Type B); and large cells, stellate or spindling (Type C). Large numbers of Type A cells were present in all tumors of the relapse-free patients but were virtually absent in the original and recurrent tumors of the early-relapse group. Conversely, Type B cells were rare in the relapse-free group, but were the most common type in the patients with early relapse. Type C cells were not seen in the former group, but were present in the latter. These observations suggest that the morphologic variations of Con A-binding histiocytes in Hodgkin's disease are associated with tumor behavior. Con A staining, which can best depict stromal histiocytes in paraffin sections, may be used to identify patients at a high risk of early relapse.