SQUAMOUS CELL CARCINOMA

Clinical features

• These tumors, when pure, account for at most 0.5% of wndometrial carcinomas; only about 70 cases have been documented. Two-thirds of the patients are postmenopausal (mean age,67 years). The tumors are stage III or IV in one-third of cases. The survical is 70-80% with stage I tumors but only 20-25% with stage III tumors.
• Predisposing factors present in some cases have included chronic pyometra, cervical stenosis, uterina prolapse or inversion, extensive endometrial squamous metaplasia, and a history of pelvic radiation. Human papillomavirus (HPV) has been detected in rare neoplasms.
• Dalrymple and Russell have questioned the validity of Fluhmann's third criterion as it artificially categorizes tumors involving both the endometriium and cervix as cervical in origin, and fails to recognize the possibility of a multifocal squamous cell carcinoma arising in the cervix and the endometrium.

Pathologial features

• The tumors often have a nonspecific gross appearance, but can occasionally have a white, sometimes even condylomatous appearance.
• Many tumors are obviously malignant on histological examination, but others are very well differentiated. In a curettage specimen, the latter can appear as fragments of almost normal-appearing, glycogenated squamous wpithelium devoid of cellular atypia. Hysterectomy in such cases may show myoinvasive, still highly differentiated, squamous cell carcinoma.
• Rare tumors have been interpreted as verrucous carcinomas are the endometrium. Bona fide verrucous carcinomas are much less common than well-differeniated squamous cell carcinomas, which have a surface verrucoid component but an infiltrative, rather than the pushing, deep border of a verrucous carcinoma.
• Some squamous cell carcinomas that have a prominent spindle cell growth of neoplastic epithelial cells are appropriately designated sarcomatoid squamous cell carcinoma.
• Horn et al, found that although four of their eight cases were immunoreactive for p16,only one cantained HPV.