Hernia Sac

Hernia sacs are common surgical specimens derived from the frequent repair of inguinal, femoral, abdominal, and umbilical hernias. The sacs usually consist of a small portion of fibroconnective tissue lined by mesothelial tissue.

A hernia sac is essentially a biopsy of the mesothelial abdominal lining and, as such, reveals malignancy in 0.1% to 0.7% of cases. The majority of these patients have a history of malignancy, and the majority of their specimens have grossly abnormal findings. However, there is a subset of these patients without a history of malignancy whose first diagnosis has resulted from the examination of a grossly normal hernia sac specimen. ^,

Approximately 22% of men undergoing inguinal hernia repair are found to have a cord lipoma. It has been questioned whether these are true neoplasms or anatomic variants. There have been 200 cases of liposarcomas of the spermatic cord, and some of these have been discovered during a herna operation. Patient age ranges from 24 to 79 years but with the majority over 60 years of age. Only 0.1% of hernia sac operations yielded an incidental liposarcoma in one study. Liposarcomas are reported to range in size from 0.4 cm to 50 cm, with an average size of 12.5 cm. This is larger than the average cord lipoma (5.5 cm). When a large fatty tumor is received, these specimens should be processed as for other sarcomas and tissue saved frozen for possible ancillary studies.

Occasionally, a groin mass (often an enlarged lymph node) is mistaken clinically for an inguinal hernia. If a lymph node is found, it should be processed as a lymph node biopsy, as the node may be involved by metastatic tumor or infection.

Not infrequently, there will be other findings in hernia sac specimens. Some of the more common ones are listed below. However, findings of clinical significance are very rare.

The value of routinely examining all hernia sacs microscopically has been questioned due to the rare occurence of findings that change clinical management (<1% in multiple studies). If the surgeon documents that the tissue removed is grossly normal, some institutions may choose to not require pathologic evaluation or only require gross evaluation. Such a policy should be written and agreed upon by the pathology department and the institution's medical staff.