Introduction: The study of a hernia sac rarely provides the evidence of a primary or metastatic malignant epithelial tumor.
Methods: We have reviewed our institutional experience with malignant epithelial tumors found in a hernia sac with the purpose of evaluating cases present/manifesting in the sac, gross appearance, histologic type, primary tumor sites, staging, and patient outcome.
Results: A total of 8,435 adult patients underwent inguinal, femoral, umbilical or abdominal hernia repair in our hospitals. Twelve (0.14 %) patients had a malignant epithelial tumor in the hernia sac. Only one of these tumors was primary and the rest metastatic. Six out of twelve tumors (50.0 %), all of them metastatic, were discovered after hernia repair (0.07 %). The mean age of the 12 patients was 68.7 ± 15.2 years (range 43-90 years). Eight patients were male (66.7 %). Six tumors were located in inguinal (50.0 %), five in umbilical (41.7 %), and one in abdominal (8.3 %) hernia sacs. Gastrointestinal cases comprised 50.0 % and gynaecologic cases 25 % of tumors. In three cases (25.0 %) the hernia sac showed no gross abnormalities. All tumors were found in an advanced stage of development and ten patients died. Mean survival of these patients after hernia repair was 275.1 ± 376.4 days (range 6-1,095 days; median 68 days).
Conclusions: Gravity, inflammatory oncotaxis, and chemotactic agents are probably operative phenomena in the development of metastatic lesions in hernia sacs. Routine microscopic evaluation of hernia sacs is not justified by the high cost. It should be reserved for selected cases based on the gross findings. Since subtle lesions may be overlooked on gross examination, particular caution should be taken with the examination of hernia sacs from older patients.