Non-squamous cell malignancies of the vulva are a large group of uncommon tumours which, nevertheless, must be considered in the differential diagnosis.
Melanoma is the most common malignancy of the vulva after squamous cell carcinoma.
2-10% of vulval malignancies are malignant melanoma.
Patients most commonly present with a mass which may be painful, bleeding or (rarely) ulcerated. On examination most are pigmented but about one quarter will be amelanotic. Imaging is used to stage regional and distant disease.
Macroscopically the tumour is usually pigmented. Ulceration is present in 5% of cases.
Microscopically there arer three growth patterns:
- Superficial spreading, which spreads radially with a central deep invasive component
- Nodular, which grows deeply relative to the surface size
- Lentiginous or Acral type, the most common in the vulva, which usually consists of spindle shaped cells in the dermis with diffuse involvement of the overlying stroma
Melanoma may contain a diverse family of cells, including pleomorphic epitheliod cells, dendritic cells and spindle shaped cells. Immunohistochemistry is usually positive for S100, melan A and HMB-45.
Bartholin Gland Carcinoma
This uncommon tumour arises from the epithelium of the Bartholin glands. It usually occurs in women over the age of 50. There is an equal split of squamous cell and adenocarcinoma. Adenoid cystic carcinoma is found in 15% of cases.
The tumour may resemble a Bartholin cyst clinically. About 1 in 5 cases will have metastases to the ipsilateral inguinal nodes.
Skin Appendage Malignancies
The vulva may develop malignancies of the skin appendages (sweat glands, hair follicles) which are homologous to their development in other sites of skin
A very rare sarcoma that occurs in females under 10 years. In the vulva it normally presents as a solid mass with pain, bleeding and ulceration. Histopathology shows spindle cells and evidence of striated muscle differentiation is usually present microscopically or with immunohistochemistry.
This sarcoma is seen more often in the vagina where it has a classical grape like appearance.
A very rare sarcoma that usually afflicts adults. They grow rapidly and cause local symptoms.
Proximal-type epitheliod sarcoma
This tumour is related to the epitheliod sarcoma of the extremities. When it occurs centrally the vulva is a common site. It metastasises early and recurs locally.
Lymphoma of the vulva is very rare. The vulva may, very rarely, be involved in leukaemia.