Squamous cell carcinoma
Squamous cell carcinoma is a type of cervical carcinoma that can be classified by the stage at which it is caught. At the early stage, it is called microinvasive carcinoma, whereas later on, it is invasive carcinoma.
Microinvasive carcinoma is an early stage of invasive cervical cancer with virtually no risk of lymph node metastases. It is defined as squamous carcinoma that has invaded less than 3mm in depth through the basement membrane. The mean age is in the 40s, which is younger than frankly invasive carcinoma, and older than dysplasia. Usually, patients will be asymptomatic, and the cervix appears normal on routine pelvic examination. It is usually diagnosed during investigation for an abnormal pap smear Microscopically, microinvasive carcinoma resembles severe dysplasia with small, irregular tongues of squamous epithelium penetrating through the basement membrane, though to a depth of less than 3mm.
Invasive squamous cell carcinoma is when there is invasion of more than 3mm through the basement membrane. The incidence of this type of cancer has dramatically decreased due to the introduction of pap smear screening, though it still remains the second most frequent female genital malignancy in North America, and 1st worldwide. After a steady decline over the years, the incidence is now increasing. Approximately 90% of cases can be associated with HPV, especially types 16 and 18, though other factors are largely unknown. Virtually all carcinomas arise from dysplasia, with a transit time of 10-15 years. Shorter transit times have been reported, and are often associated with immunodeficiency states.
Grossly, there are focal indurations, shallow ulcers and elevated, friable granular areas early on. In advanced cases, the appearance may be endophytic (ulcerated, nodular) or exophytic (polypoid, papillary). Microscopically, one can see sheets and cords of malignant squamous cells infiltrating through the basement membrane and into the underlying soft tissue. Cells are usually large and may or may not show keratinization. At later stages, the ability of pap smears to detect carcinoma is limited, as blood, necrotic debris and inflammatory cells may obscure malignant cells. If carcinoma is suspected, a biopsy is necessary.
Invasive squamous cell carcinoma of the vulva is associated with vulvar intraepithelial neoplasia (VIN) and Human papillomavirus (HPV; especially type 16), or may be associated with lichen sclerosus. Overall, this malignancy is very uncommon (3% all female genital cancers), but is the most common subtype of vulvar carcinomas. Symptoms include a mass lesion, pruritus, burning, pain, and bleeding.
Grossly, an exophytic mass or endophytic ulcerated lesion is visible, and may have variable colour (red, white or brown). The labia majora and minora are involved. Microscopically, malignant squamous epithelium can be found in the dermis], and lymphatic invasion may be seen. Microinvasive squamous cell carcinoma has < 1.0mm invasion.
Diagnosis is made by incisional or excisional biopsy and microscopic examination. Microinvasive and verrucous neoplasms have an excellent prognosis, especially when confined to the vulva and without metastases.