Early invasive vulvar squamous cell carcinoma (SCC) with less than 1.0 mm of invasion (FIGO stage IA) has been shown to have a minimal risk of lymph node metastasis and is associated with an excellent prognosis. The prognostic significance of other histologic parameters other than depth of invasion, however, remains controversial. Seventy-eight consecutive cases of vulvar SCC having a depth of invasion of 5.0 mm or less were reviewed and the clinical outcome compared with the type of surgical excision, the presence of concurrent lymph node metastases, the depth of tumor invasion, the tumor thickness, the tumor horizontal spread, the estimated tumor volume, tumor histologic subtype, tumor histologic grade, tumor pattern of invasion, tumor multifocality, presence of perineural invasion, presence of angiolymphatic invasion and the presence of precursor lesions, including the type of vulvar intraepithelial neoplasia and presence of lichen sclerosus. The only histologic feature for predicting concurrent lymph node metastasis was tumor depth of invasion. The 3 most important features of stage IA tumors in predicting tumor recurrence were the depth of invasion, presence of SCC at the surgical margins, and the histologic grade.