Cancer to the inguinal nodes from an unknown primary site

Three cases of metastatic cancer to inguinal lymph nodes from unknown primaries are presented. All three patients had exhaustive workups which produced no primary lesions. There were two cases of metastatic squamous cell carcinoma and one of melanoma. A review of the literature shows that it is unusual to have metastatic disease without detectable primary lesions to the inguinal lymph nodes. Furthermore, and more importantly, these cases open discussion of recent concepts of tumor biology. Based on these newer concepts, suggestions are made concerning the examination and treatment of these unusual lesions.