A 28-year-old woman undergoes laparoscopic removal of a left ovarian cyst. Intraoperatively, the surgeon identifies a mature cystic teratoma (dermoid cyst) filled with sebaceous material and hair. During careful dissection, a fleshy nodule projecting from the cyst wall—marked as **D** in the diagram—is identified. Which of the following best describes the clinical significance of the structure marked **D**?

Explanation

## Why option 1 is right The structure marked **D** is the Rokitansky protuberance (mamillary process)—a characteristic fleshy nodule projecting from the cyst wall of a mature cystic teratoma. This nodule is the area from which teeth, bone, cartilage, hair follicles, and other tissues derived from all three germ layers preferentially arise. Critically, the Rokitansky protuberance is the site most at risk for malignant transformation (occurring in 1–2% of cases, usually squamous cell carcinoma in post-menopausal women), and it is therefore the area that must be carefully sampled during histopathologic examination. Understanding this anatomic landmark is essential for both surgical technique and pathologic assessment. ## Why each distractor is wrong - **Option 2**: While the cyst wall is indeed thick and fibrous, the Rokitansky protuberance is not simply the fibrous capsule itself. It is a specific fleshy nodule within or projecting from the wall, and recurrence is primarily related to incomplete cystectomy of the epithelial lining, not to the protuberance alone. The recurrence rate is 3–15% after cystectomy, but this is not the primary clinical significance of the protuberance. - **Option 3**: The sebaceous material filling the cyst cavity is produced by sebaceous glands (ectoderm-derived) distributed throughout the cyst wall, not specifically from the Rokitansky protuberance. The protuberance is the site where organized tissues (teeth, bone) arise, not the primary lipid-secreting region. - **Option 4**: While the cyst does have a blood supply, the Rokitansky protuberance is not itself a vascular pedicle. It is a tissue nodule, not a vascular structure. The ovarian blood supply (ovarian artery/vein) supplies the entire ovary and cyst, but this is not the defining feature of the protuberance. **High-Yield:** The Rokitansky protuberance is the nodule where teeth and bone arise within a dermoid cyst—always sample it histologically because it is the site of malignant transformation risk (1–2%, usually SCC in women >50 years). [cite: Robbins Pathologic Basis of Disease 10e Ch 22; Williams Gynecology 4e Ch 35]