- Design
- Case series with immunohistochemical and molecular profiling
- Population
- 4 women aged 34–48 with vaginal or Bartholin gland region tumours
- Primary outcome
- Morphological, immunohistochemical and molecular features
- Effect
- All ER/PR-positive; BAP1 loss with germline variant in 2/4; no recurrence (8 mo–15 y)
An American Journal of Surgical Pathology series describes four cases of a mesenchymal tumour the authors name vulvovaginal epithelioid mesenchymal neoplasm with 'deciduoid' morphology. The tumours arose in women aged 34 to 48 in the vagina or Bartholin's gland region, measured 25 to 55 mm, and were solid and well circumscribed.
Microscopically they were made up of epithelioid cells, with fewer spindle cells, carrying abundant granular, glassy eosinophilic cytoplasm, with prominent vessels and a mild lymphoid infiltrate. All were diffusely positive for ER, PR, CD63 and vimentin. Two showed BAP1 loss on immunohistochemistry and carried inactivating germline BAP1 variants. All had copy-number loss on 14q and/or 17q and MAPK pathway alterations. None recurred over follow-up from 8 months to 15 years.
Four cases cannot define behaviour, but the practical point is clear: in an unusual epithelioid vulvovaginal tumour, BAP1 immunohistochemistry is cheap, and loss should prompt referral for germline testing because of the associated risks of mesothelioma, uveal and cutaneous melanoma, and renal cancer.
- Consider this entity for a circumscribed vulvovaginal tumour of epithelioid cells with glassy eosinophilic cytoplasm.
- Expect diffuse ER, PR, CD63 and vimentin positivity without another consistent lineage marker.
- Add BAP1 immunohistochemistry to the work-up of unusual epithelioid vulvovaginal tumours.
- BAP1 loss should prompt referral for germline testing and family counselling.
- None of the four tumours recurred, but behaviour is not yet established.
Why it matters
A diagnosis in a gynaecological tumour can identify a cancer predisposition syndrome affecting the patient and her relatives.
Don't overread it
This is a four-case series; prognosis and the true frequency of germline BAP1 variants are unknown.
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