Reconsidering Routine Appendectomy in Ovarian Neoplasms: Implications for Diagnostic Staging
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Keywords
Reconsidering Routine Appendectomy , Ovarian Neoplasms, Implications for Diagnostic Staging
Abstract
Dear Editor,
Although the current International Federation of Gynecology and Obstetrics (FIGO) guidelines permit omitting appendectomy if the organ appears macroscopically normal,[1] this "visual-only" assessment lacks diagnostic validity in complex ovarian neoplasms. Preserving the appendix creates a “diagnostic vacuum”, resulting in under-staging and diagnostic uncertainty. Amidst the ongoing debate regarding appendectomy during gynaecological surgeries, the necessity of an appendectomy is often unknown until the final pathology report. [2,3] This letter highlights two scenarios where its absence almost hindered a definitive diagnosis.
Brief Background and Guidelines on the Current FIGO Recommendation on Cancer of the Ovary, Fallopian Tube, and Peritoneum: 2025 Update
In 2025, Renz et al. established the current global benchmark for staging ovarian, fallopian tube, and primary peritoneal cancers,[1] shifting towards selective surgery to minimize morbidity. Under these standards, appendectomy is indicated only for mucinous tumours, pseudomyxoma peritonei, or grossly abnormal appendix (defined by increased diameter, discoloration, or visible nodules). [4] This conservative posture relies on the statistically low rate of occult (microscopical) primary appendiceal tumours in a macroscopically normal appendix. [5]
However, a critical clinical gap exists where intra-operative frozen section is unavailable. Without real-time histology, surgeons are unable to definitively distinguish mucinous from non-mucinous ovarian epithelial tumours during primary surgery. Omitting appendectomy based on a “grossly normal” appearance frequently necessitates a second, avoidable surgery for diagnostic validation and staging if a mucinous morphology is later confirmed. Consequently, lack of immediate diagnostics transforms conservative surgery into a pathway of increased morbidity and delayed staging, often leaving the primary site as “undesignated” when definitive identification is impossible. [4,6,7]
Brief Background of the College of American Pathologists (CAP) Current Cancer Protocol (2024) for the Examination of Specimens from Patients with Primary Tumours of the Ovary, Fallopian Tube, or Peritoneum
The College of American Pathologists (CAP) Cancer Protocol (Version 1.5.0.0, June 2024), aligned with National Comprehensive Cancer Network [NCCN] guidelines, establishes the mandatory framework for pathological evaluation and synoptic reporting of ovarian, fallopian tube, and primary peritoneal neoplasms. Central to this protocol is the requirement that the “Primary Site” (Note C) be explicitly identified. [8] The guidelines acknowledge a significant historical shift in diagnostic practice, where the determination of the primary site was often based simply on the “dominant mass” encountered during surgery. However, the CAP protocol emphasizes that this historical reliance on organ size frequently resulted in extra-ovarian primary sites, such as those originating in the appendix or other gastrointestinal primaries, being mistakenly identified as primary ovarian or peritoneal neoplasms.
The most dangerous diagnostic hurdle in ovarian mucinous neoplasms is the “maturation phenomenon” or “mimicry study,” where metastatic low-grade appendiceal mucinous neoplasm (LAMN) to the ovary histologically mimics a primary ovarian mucinous cystadenoma or carcinoma. [9,10] These cases are often missed without examining the appendiceal source. For the pathologists, the absence of the appendix, the most common site of metastatic origin for most pelvic tumours presents a critical diagnostic and documentation challenge. While CAP technically allows for “undesignated” or “unknown” primary site categories, it strongly advises against their use. Instead, CAP protocol encourages using validated algorithms and criteria such as the Seidman or Yemelyanoava Algorithms, and Hart- Norris Criteria in differentiating primary bilateral ovarian tumours from metastatic ovarian tumours. [11, 12, 13] In the absence of a histological negative from the appendix, pathologists are unable to fulfill the mandate for a primary definitive site with absolute certainty. (Table 1) shows a comparison of recommendations and protocols for Appendectomy in ovarian neoplasms.
References
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