The most common histological type of vulval cancer is?
**Core Concept**
Vulval cancer is a rare type of cancer that affects the vulva, the external female genitalia. The most common histological type of vulval cancer is a type of squamous cell carcinoma, which originates from the squamous epithelial cells that cover the vulva.
**Why the Correct Answer is Right**
Squamous cell carcinoma of the vulva typically arises from the keratinizing squamous epithelium of the vulva, which is exposed to chronic irritation and trauma. The pathogenesis of vulval squamous cell carcinoma involves the accumulation of genetic mutations in the p53 and pRb tumor suppressor genes, leading to uncontrolled cell proliferation and tumor formation. The most common location of vulval squamous cell carcinoma is the labia majora.
**Why Each Wrong Option is Incorrect**
**Option A:** Basaloid carcinoma is a rare subtype of vulval cancer that accounts for less than 5% of cases. It is characterized by a distinctive histological appearance and is often associated with human papillomavirus (HPV) infection.
**Option B:** Adenocarcinoma is a type of cancer that originates from glandular epithelial cells, which are not typically found in the vulva. While adenocarcinoma can occur in the vulva, it is a much rarer type of vulval cancer compared to squamous cell carcinoma.
**Option C:** Melanoma is a type of cancer that originates from melanocytes, which are pigment-producing cells found in the skin. While melanoma can occur in the vulva, it is a rare type of vulval cancer compared to squamous cell carcinoma.
**Clinical Pearl / High-Yield Fact**
The mainstay of treatment for vulval squamous cell carcinoma is wide local excision, which involves surgically removing the tumor along with a margin of normal tissue. Radiation therapy and chemotherapy may be used in combination with surgery to treat more advanced cases of vulval cancer.
**Correct Answer:** C.