Appendix: Surgical Pathology Dissection

Appendix

Simple Appendectomies

The appendix is a common specimen in the surgi-cal pathology laboratory. The dissection of these specimens is not complex, since most appendec-tomies are performed for simple acute appendici-tis. Even so, the appendix is all too often not examined appropriately. Cursory examination of the appendix is a pitfall to be avoided. Instead, develop the habit of thoroughly examining every appendix. Regard every appendiceal specimen as an opportunity to uncover unsuspected patho-logic processes.

The major objectives in dissecting the simple appendectomy specimen are to document the presence or absence of inflammation and to search for incidental neoplasms. These objec-tives are met by examining each component of the appendix—the serosa, wall, mucosa, and lumen— in a sequential manner. Begin by inspecting the outer surface of the appendix and the attached mesoappendix. Inflammatory processes often convert the glistening, smooth, tan serosa into a surface that is dull, shaggy, and discolored. Carefully look for perforations. Small transmural perforations that are not easily seen can some-times be demonstrated by gently infusing forma-lin into the lumen of the appendix using a syringe. Document the dimensions of the specimen, and then section the appendix so that the wall, the mucosa, and the lumen can be evaluated. As illus-trated, bread-loaf the body of the appendix using thin transverse sections, and bivalve the distal 2-cm tip of the appendix using a longitudinal section. Inspect the wall for masses, strictures, edema, and other inflammatory changes. Finally, evaluate the mucosa and the luminal contents for fecaliths, pus, and collections of mucus. If a neoplasm is present, submit a shave margin from the base of the appendix, and be sure to document the size of the tumor, the distance from the tumor to the surgical margin, and the layers of the appendix that are involved. When the lumen is obstructed, attempt to identify the nature of the obstruction, keeping in mind that most tumors of the appendix are discovered in specimens resected for other reasons.

Sections for histologic evaluation should in-clude a transverse section through the base and body and a longitudinal section of the tip. Include a portion of the attached mesoappendix. For a normal-appearing appendix removed by inciden-tal appendectomy, one section each from the base, body, and tip placed into a single tissue cas-sette will suffice. For an inflamed appendix, addi-tional sections may be required to demonstrate points of perforation or luminal obstruction. If a mass or mucocele is present, the entire appendix should be submitted in a sequential fashion. The most proximal section from the base of the appen-dix represents the margin of resection.

Important Issues to Address in Your Surgical Pathology Report on Appendectomies

·   What procedure was performed, and what structures/organs are present?

·   What are the nature and extent of any inflam-matory processes present (e.g., acute appendi-citis, abscess formation, gangrene)? Be sure to mention the presence or absence of perfora-tions and peritonitis.

·            What are the type, grade, size, location, and extent of any incidental neoplasms identified? Is the tumor present at the resection margin?