Frozen Section on a Small Ovarian Mass
A 34-year-old woman undergoes laparoscopy for a 6 cm right ovarian mass found on ultrasound. Intraoperatively the mass is smooth, cystic, and adherent to the pelvic sidewall; the contralateral ovary is normal. The surgeon requests a frozen section to decide between cystectomy and staging. The frozen section shows a cystic lesion lined by a single layer of cuboidal to columnar cells with mild atypia, hobnail cells, and a fibromatous stroma; no destructive invasion, no back-to-back glands, and no necrosis are seen. The permanent sections, available 4 days later, show the same features with focal mild nuclear atypia but no invasion. The patient is anxious about cancer and asks whether she needs a second surgery.
1. Give the differential diagnosis for the frozen-section findings and state the most likely diagnosis.
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The differential for a cystic ovarian lesion with cuboidal/columnar lining, hobnail cells, and fibrous stroma includes serous cystadenoma, serous borderline tumor, clear cell carcinoma, endometriotic cyst, and a small well-differentiated Sertoli-Leydig or other sex cord-stromal tumor. The absence of destructive invasion, back-to-back glands, and necrosis, together with a single epithelial layer and a fibromatous wall, favors a benign serous cystadenoma with hobnail change or a serous cystadenofibroma. Clear cell carcinoma is a consideration because hobnail cells are characteristic, but it would show atypia, mitoses, and invasive architecture. The frozen section cannot fully exclude a borderline tumor because sampling is limited, so the permanent sections and adequate sampling are decisive.
2. How should the frozen-section result be communicated to the surgeon, and what is the intraoperative decision framework?
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The pathologist should state explicitly that the frozen section shows a benign-appearing cystic lesion with no evidence of invasion but that borderline or malignant change cannot be excluded on limited sampling. The surgeon should weigh ovarian preservation in a 34-year-old against the risk of underdiagnosis. A reasonable approach is cystectomy with careful inspection of the capsule and submission of the entire cyst wall for permanent sections, avoiding spillage; if the mass is adherent or ruptured, staging or at least peritoneal washings and biopsy of the adherent area may be warranted. The judgment call is to avoid overcommitting to staging on a benign frozen section while not dismissing the possibility of a borderline tumor.
3. The permanent sections confirm a benign serous cystadenoma. What follow-up and counseling are appropriate, and what is the role of the adherent pelvic sidewall?
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Because the lesion is benign, no staging or adjuvant therapy is needed. The patient should be counseled that the cyst was benign, that recurrence after complete cystectomy is uncommon, and that she should have clinical follow-up with ultrasound if symptoms recur. The adherence to the pelvic sidewall raises the question of adhesions or endometriosis rather than malignancy; the surgeon should have documented whether the adherence was lysed and whether the capsule was intact. If the cyst ruptured during surgery, the risk is chemical peritonitis and adhesion formation, not tumor spread, because the lesion is benign. The key point is that the final diagnosis, not the intraoperative appearance, drives management.