Ovary

• Most are unilateral
• Typically well circumscribed and unencapsulated
• Yellow to tan and soft to firm cut surface
  • May show white fibromatous areas
  • Variable hemorrhage, necrosis and cystic spaces
• Range: 3.0 - 20 cm (mean: 12.8 cm) (Am J Surg Pathol 2022;46:1599)

Contributed by Glenn McCluggage, M.D.

Which of the following is true regarding the ovarian lesion pictured above?

1. It has a poor prognosis
2. It is negative for epithelial membrane antigen (EMA)
3. It is positive for mucicarmine
4. It is typically bilateral
5. Treatment involves local excision with adjuvant chemotherapy

B. It is negative for EMA. This is a signet ring stromal tumor. Answers A and E are incorrect as this is a benign entity for which excision is curative. Answer D is incorrect because the tumor is usually unilateral but may rarely be bilateral. Answer C is incorrect as it is negative for mucicarmine. Given the signet ring cell morphology and cytokeratin expression, there may be concern for a metastatic mucinous carcinoma with signet ring cells (i.e., Krukenberg tumor). However, EMA helps to distinguish between the 2 entities as it is negative in signet ring stromal tumor but positive in Krukenberg tumor.

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Reference: Signet ring stromal tumor

A 32 year old woman without significant medical history presents with abdominal pain. Workup reveals a 2 cm right adnexal mass on ultrasound and she undergoes salpingo-oophorectomy. Histologic examination of the ovarian tumor reveals sheets of cells with crescent shaped nuclei and intracytoplasmic vacuoles. The vacuoles are negative for mucicarmine and periodic acid Schiff (PAS). The cells are positive for inhibin and steroidogenic factor 1 (SF1) but negative for cyclin D1 and epithelial membrane antigen (EMA). Beta catenin shows cytoplasmic expression. What is the likely diagnosis?

1. Adult granulosa cell tumor
2. Brenner tumor
3. Krukenberg tumor
4. Microcystic stromal tumor
5. Signet ring stromal tumor

E. Signet ring stromal tumor. All of the answers above are reasonable considerations for which clinicopathologic and immunohistochemical features should aid towards the diagnosis; however, in contrast to the other options, signet ring stromal tumors should present as a unilateral mass with expression of sex cord markers and negativity for cyclin D1 and beta catenin (membranous positivity only). Answer A is incorrect because adult granulosa cell tumor usually occurs in postmenopausal females who present with estrogenic manifestations. Histologically, multiple growth patterns are common and cells are usually small with coffee bean nuclei, longitudinal nuclear grooves and scant cytoplasm. Answer C is incorrect because Krukenberg tumor also presents in older females, usually as bilateral ovarian masses, with positivity for cytokeratin and negativity for sex cord markers. Answer D is incorrect because microcystic stromal tumor can show signet ring cells along with variably thick collagenous septations and strong nuclear expression of beta catenin and cyclin D1. Answer B is incorrect because Brenner tumor usually shows a nested architecture of transitional type cells embedded in a fibromatous stroma and should be positive for CK7 and EMA.

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Reference: Signet ring stromal tumor