Squamous cell carcinoma of the uterine cervix--a review with emphasis on prognostic factors and unusual variants.

Although the incidence of squamous cell carcinoma of the cervix has declined in recent years, it remains the most common type of cervical cancer in our society. In this review, the salient pathologic features of squamous cell carcinoma are discussed. Early invasive, International Federation of Gynecology and Obstetrics (FIGO) stage la carcinoma has been a source of controversy in diagnosis and therapy for many years. Specific requirements must be met in order to make this diagnosis. Most importantly, the cervical conization specimen must be handled properly, so that the features of tumor dimensions, vascular involvement, and completeness of excision can be correctly evaluated. Important diagnostic and prognostic pathologic findings of early invasive carcinoma are discussed. The risk of lymph node metastasis in lesions with depths of invasion up to 3 mm is less than 1%. This risk increases significantly with deeper levels of invasion. In the area of frankly invasive squamous cell carcinoma of the cervix, certain pathologic features have been shown to be clinically relevant. These include the extent of local disease, cell type, and the presence of vascular or lymphatic invasion. Regarding cell type, it is critical to distinguish between poorly differentiated small cell squamous carcinoma and small cell undifferentiated carcinoma, as the prognosis for these tumors may differ. Finally, several rare but pathologically distinct variants of squamous cell carcinoma of the cervix are reviewed, with emphasis on differential histologic features. As they often have different natural histories than typical squamous cell carcinoma, correct diagnosis of these lesions is vital.