Sarcomatous change can occur in the tissues of the müllerian system, including the endometrial stroma and myometrium. Mixed müllerian sarcomas may include elements not native to the genital tract such as cartilage or bone (heterologous type). Sarcoma of the uterus, whether primary or occurring secondary to a preexisting ﬁbroid, is a relatively rare disease. Of all malignancies of the female genital tract, sarcomas represent less than 5% of uterine malignancies, or roughly 1 of 800 smooth muscle tumors, with a prevalence of 0.67 per 100,000 women older than 20 years. The incidence of sarcomatous degeneration of a myoma is less than 1%. It has been found in ages from childhood to many years after menopause. There appear to be no genetic pattern, and though sarcomas are reported more often in black women, there is no racial predisposition. Leiomyomas have been proposed as risk factors for these tumors as have estrogen and obesity, though evidence is lacking. The use of oral contraceptives is associated with a reduced risk.
These tumors grow with surprising rapidity. Even in children, tumors have been observed that were larger than a pregnant uterus at term. The grave prognosis of such a tumor, even when treated with radical surgery, makes it advisable to cut open all leiomyomas at the time of their removal and submit all surgical specimens for histologic evaluation. A sarcoma is most apt to appear at the center of the larger tumors. It is easily recognized on cross sections, as it is soft and meaty and lacks the ﬁrm, characteristic whorled appearance of a myoma. Inadequate blood supply is often responsible for a central necrosis or hemorrhage.
Sarcomas may originate in any part of the uterus that contains mesodermal tissue, but whether the tumor is a mural or endometrial sarcoma, whether it derives from connective tissue of the endometrium, endocervix, or blood vessels or develops from muscle cells of the myometrium or myoma cells, and whether it may be classiﬁed as spindle cell or round cell or mixed cell sarcoma, its invasive and metastatic tendencies are seemingly the same. Size and extent of the tumor are more important, as far as the prognosis is concerned, than is its location or its histologic classiﬁcations.
The diagnosis may be difﬁcult in many cases and is not necessarily ﬁnal until the pathologist has rendered the verdict after extensive examination of the tumor postoperatively. Because of technical difﬁculties, biopsy specimens examined by the frozen-section technique are seldom helpful.
A primary sarcoma arising directly from the uterine body may easily be mistaken for a benign submucous ﬁbroid. At times, it may be impossible to differentiate the spindle cell sarcoma from a benign cellular ﬁbroid without resorting to microscopic examination, which will reveal the presence of mitoses in the case of the former.
Occasionally, uterine polyps show sarcomatous degeneration. When this has occurred, the only treatment is that of radical panhysterectomy.
The “grape” sarcoma or sarcoma botryoides is very rare. It consists of multiple, soft, berrylike formations, varying in size from that of a pea to that of an olive. This tumor carries a grave prognosis and occurs almost exclusively in young children. Clusters of tumor masses arising from the cervix or the vagina may present them-selves at the introitus, or they may be extruded by hemorrhage. In view of the rapid growth of the neoplasm, a very early and radical hysterectomy with extensive pelvic node dissection offers the only hope of survival. On the occurrence of vaginal bleeding in any young child, the possibility of this serious neoplasm must not be overlooked.