The diagnostic challenge of primary adenocarcinoma of the vulva: a case report

Abstract

The diagnosis and classification of primary adenocarcinoma of the vulva is a complicated and understudied area, as this is a rare histological subtype of vulvar cancers. The differential diagnoses include extramammary Paget disease with invasion, adenocarcinoma arising from mammary-like glands, skin adnexal structures as well as Bartholin’s glands in the vicinity. We report a case of extramammary Paget disease which first presented as primary vulvar adenocarcinoma. The patient was a 71-year-old woman who presented with a swelling at the external genitalia. Clinical examination revealed a right vulvar lump, with eczematous features on the overlying skin. The lump was biopsied and was called Paget disease with underlying adenocarcinoma. Subsequently, the patient underwent radical vulvectomy and bilateral groin and pelvis dissection. The resection specimen was reported as extramammary Paget disease, with dermal invasion forming a poorly differentiated adenocarcinoma showing strong HER-2 expression on immunohistochemistry. This case illustrates the diagnostic challenge in the classification of primary vulvar adenocarcinoma. Positivity for HER-2 has been reported in Paget-associated vulvar adenocarcinoma and might offer potentially actionable targets on the selection of therapy, especially in advanced metastatic disease.