A 46-year-old woman undergoes an abdominal hysterectomy for a "fibroid" uterus. The surgeon requests a frozen section on the tumor, which is deferred because of the lesion's degree of cellularity. Which of the following criteria will be used by the pathologist in determining benignancy versus malignancy in permanent sections?
"Fibroids" of the uterus are among the most common abnormalities seen in uteri. They arise in the myometrium, submucosally, subserosally, and midwall, both singly and several at a time. Sharply circumscribed, they are benign smooth-muscle tumors that are firm, gray-white, and whorled on cut section. Their malignant counterpa, leiomyosarcoma of the uterus, is quite rare in the de novo state and arises even more rarely from an antecedent leiomyoma. Whereas cell pleomorphism, tissue necrosis, and cytologic atypia per se are established criteria in assessing malignancy in tumors generally, they are impoant to the pathologist in uterine fibroids only if mitoses are also present. Regardless of cellularity or atypicality, if 10 or more mitoses are present in 10 separate high-power microscopic fields, the lesion is a leiomyosarcoma. If five or fewer mitoses are present in 10 fields with bland morphology, the leiomyoma will behave in a benign fashion. Problems arise when the mitotic counts range between three and seven per 10 fields with varying degrees of cell and tissue atypicality. These equivocal lesions should be regarded by both pathologist and clinician as "gray-area" smooth-muscle tumors of unpredictable biologic behavior. Founately, the gray-area leiomyoma of the uterus is rarely seen. Thus mitoses are the most impoant criteria in assessing malignancy in smooth-muscle tumors of the uterus. Reference: Robbins & Cotran Pathologic Basis of Disease, 9edition
Mitotic rate
Cell pleomorphism
Cell necrosis
Nucleus-to-cytoplasm ratio
miscellaneous