SEROSAL REACTION IN CHRONIC GASTRIC-ULCERS - AN IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL-STUDY

Aim-To study the serosal reaction in gastrectomy specimens with benign chronic peptic ulcers. Methods-Gastrectomy specimens were fixed in ne utral buffered formalin and paraffin wax, and examined using immunohis tochemical and ultrastructural techniques. Results-Nine of the 22 (41% ) cases examined showed reactive hyperplasia of the serosal cells. The cells were predominantly spindle-shaped and were positive on staining with Cam 5.2, AE1/3 and for vimentin. Eight of nine were also positiv e for smooth muscle actin and five for desmin. Ultrastructural analysi s of these cells suggests that they may be myofibroblastic in nature. Conclusions-These results support the concept of ''multipotential'' su bserosal cells which may differentiate into surface serosa or, in the reactive state, modulate the thin cytoskeletal filaments and become mo re myofibroblastic. Particular care should be taken not to confuse the se reactive serosal cells with carcinoma or smooth muscle tumours in e ndoscopic biopsy specimens.