BACKGROUND:Several studies have attempted to investigate the association of thermal difference between malignant tumors and inflammatory benign lesions. In this work, we evaluated whether thermal heterogeneity of solid tumors in the stomach constitutes a marker for the diagnosis of benign, preneoplastic, and malignant lesions. STUDY:A thermistor probe was used that attached to the distal end of a long and steerable, 3fr-thermography catheter passed through the biopsy channel of the gastroscope and came in touch with the stomach epithelium to measure temperature differences (DeltaT) between normal tissue and various types of lesions. The method was applied in 8 patients with benign hyperplastic gastric lesions, 19 patients with gastritis, 9 patients with peptic ulcer, 7 patients with dysplasia and 11 patients with gastric adenocarcinoma. RESULTS:Progressive changes in DeltaT between hyperplastic gastric lesions, gastritis, ulcer, dysplasia and adenocarcinoma were observed (P < 0.001). Statistical analysis showed that DeltaT greater than 1.7 degrees C, constitutes a crucial point for the diagnosis of malignancy, in stomach lesions, with sensitivity (72%) and specificity (94%). CONCLUSIONS:These findings suggest that the detection of DeltaT, between normal tissue and neoplastic lesions, could be useful in clinical practice for the differential diagnosis of stomach lesions, even in the early stages.