- Design
- Case series with immunohistochemical and molecular profiling
- Population
- 4 women aged 34–48 with vulvovaginal epithelioid mesenchymal tumours
- Primary outcome
- Morphological, immunophenotypic and molecular features; recurrence
- Effect
- 2 of 4 with germline BAP1 variants; no recurrence over 8 months to 15 years
A case series described four cases of a vulvovaginal mesenchymal tumour in women aged 34 to 48, arising in the vagina or the Bartholin gland region and measuring 25 to 55 mm.
The tumours were well circumscribed, made up of epithelioid and some spindle cells with abundant glassy, granular eosinophilic cytoplasm resembling decidua, with prominent vessels and mild lymphoid infiltrate. All were diffusely positive for oestrogen and progesterone receptors, CD63 and vimentin. Two showed loss of BAP1 staining and carried inactivating germline BAP1 variants. All had copy-number loss at 14q and/or 17q and MAPK pathway alterations. None recurred over 8 months to 15 years.
The main diagnostic risk is mistaking this for decidualised stroma, an epithelioid smooth muscle tumour or another epithelioid neoplasm.
The clinical point is the germline link: BAP1 loss in such a tumour should prompt referral for genetic assessment, given associated risks of uveal and cutaneous melanoma, mesothelioma and renal cell carcinoma.
- Consider this entity for a circumscribed vulvovaginal tumour with deciduoid epithelioid cells.
- Add BAP1 immunohistochemistry to the panel.
- Recommend genetic referral when BAP1 staining is lost.
- Note that none of the four recurred, which may inform the clinical message.
Why it matters
A small vulval mass may be the first sign of a cancer predisposition syndrome affecting the whole family.
Don't overread it
Four cases define an entity; they cannot give its true behaviour or how often it is germline-associated.
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