A histopathologic study on the effects of radiofrequency thermotherapy on malignant tumors of the lung.

Malignant cells are thermosensitive but this does not fully explain the wide-spread pathologic changes observed in solid cancers following local therapy with radiofrequency heating. The histopathology of human malignant tumors after radiofrequency thermotherapy reveals not only the expected degeneration of tumor cells, but significant changes in the tumor's stroma as well. Stromal blood capillary walls are massively infiltrated with round cells and undergo degenerative changes leading to necrosis and obliteration of the tumor's vascular supply. Extensive infiltration of the stroma with the host's round cells occurs. Following focal necrosis and rupture of the stroma, pools of lymphocytes establish direct contact with heat damaged malignant cells leading to further destruction of persisting tumor. The histologic signs of the generalized breakdown of lung tumors consequent to radiofrequency heat-therapy bear close resemblance to lesions in acutely rejecting organ allografts.