Inflammatory oncotaxis after testing the skin of the cancer patient

A case is presented in which a patient with Dukes C adenocarcinoma of the sigmoid colon subsequently developed a soft tissue metastasis at the site of a marked delayed type hypersensitivity response to the commonly used skin test antigen Dinitrochlorobenzene (DNCB). A possible cause and the implications of this rare occurrence are discussed. It is concluded that the inflammatory response to DNCB and the subsequent metastasis in this patient were causally related. Physicians who utilize skin testing in cancer patients should be aware of the possibility of "inflammatory oncotaxis" with the development of metastatic lesions in unusual places.