Histopathological criteria for uterine sarcomas have greatly evolved over the last few years. As per a large series with 127 cases including carcinosarcomas, the most common uterine sarcoma were leiomyosarcoma and carcinosarcoma [9] (Fig. 30.1). However, leiomyosarcomas and endometrial stromal sarcomas accounts for 66–23 %, respectively, of all uterine sarcomas after excluding carcinosarcomas, with all of the other subtypes being exceedingly rare. According to most recent and largest series (n = 419) in Norway on uterine sarcomas from 1970 to 2000 using 2003 WHO classification by Abeler and colleagues (excluding carcinosarcomas), 62 % were leiomyosarcomas, 20 % were ESSs, and 18 % were rare subtypes including undifferentiated sarcomas (6 %), adenosarcomas (5.5 %), sarcoma, not otherwise specified (NOS) (4.5 %), rhabdomyosarcoma (<!%), giant cell sarcoma (<!%), and perivascular epithelioid cell tumor (PEComa; <1 %) [10].

According to a published series, the median ages reported ranges from 48 to 57 years for leiomyosarcoma, 57 to 67 years for carcinosarcomas, 42 to 51 years for ESSs, and 58 to 66 years for adenosarcomas [5]. In a review of 208 patients with leiomyosarcomas from the Mayo clinic, only 41 % were postmenopausal [11]. Thus, many patients with carcinosarcoma are postmenopausal at the time of diagnosis, whereas patients with leiomyosarcoma, ESS, or undifferentiated sarcoma may be pre- or postmenopausal at the time of diagnosis. This would have potential implications in terms of fertility for these patients.

Genetic factors have been suggested to play a role, as incidence is twice as high among black women compared to white women. This race-specific incidence pattern is reversed in endometrial carcinoma, in which the incidence among white women is three times higher than that among black women [5, 12]. In a series by Zelmanowicz et al., women with carcinosarcoma are more likely to be of African American descent than those with endometrial adenosarcomas (among 453 patients and controls, 28 % versus 4 %, p = 0.001) [8]. Then, Brooks et al. reported that the age adjusted incidence of uterine sarcomas in African American women was twice that of controls. The age-adjusted incidences of leiomyosarcomas for black and white women, respectively, were 1.5 and 0.9 per 100,000. Similarly, those for carcinosarcoma in black and white women, respectively, were 4.3 and 1.7 per 100,000 [13].

The development of the basic understanding of uterine sarcoma has been slow. The majority of cases are felt to be sporadic, with no specific etiology, and most have complex karyotypes [14]. However, specific chromosomal translocations have been identified in an increasing number of uterine sarcomas, resulting in fusion genes that are constitutive and involve activation of transcription factors [5, 15].

The most common presenting symptom of uterine sarcomas is abnormal uterine bleeding (pre- or postmenopausal bleeding), and is nearly universal in those with carcinosarcoma, but may occur in as few as 40 % of those with leiomyosarcomas [1, 5, 6]. (Table 30.2).

Carcinosarcomas usually occur in an older age group; most patients being postmenopausal. The frankly malignant variants grow rapidly and at physical examination, 50–95 % of patients have enlargement of the uterus with 50 % of patients having protrusion of a polypoidal lesion through the endocervical canal. In advanced cases, presentation maybe similar to that of ovarian cancer with pleural effusion, ascites, and adnexal masses. Uterine curettage usually detects malignant tissue in the uterus, as it is a lesion that arises in the endometrium (unlike true uterine sarcoma that often does not have an endometrial component).

Uterine enlargement and a presumptive diagnosis of uterine leiomyomas, leiomyomas are nearly universal findings in patients with leiomyosarcoma. They usually present in women above 40 years of age and majority of these tumors arise de novo, with less than 5 % arising from malignant transformation of an existing leiomyoma. Occasionally, the presentation may be that of hemoperitoneum due to tumor rupture, extrauterine extension, or metastases such as persistent cough, back pain, and ascites [27] Berchuck et al. reported that in 14 patients with leiomyosarcomas undergoing dilatation and curettage, a prehysterectomy diagnosis was made in only 8 (31 %).

Endometrial stromal sarcoma usually presents between 40 and 55 years of age. Again, the most common presenting symptom is abnormal uterine bleeding with some women presenting with pelvic pain and/or dysmenorrhea but as many as 25 % of them may be asymptomatic. In a report by Memorial Sloan-Kettering Cancer Center, endometrial stromal sarcoma was diagnosed as an incidental finding in 42 % of cases [28]. Some cases have been reported in women with ovarian polycystic disease, after estrogen use, or tamoxifen therapy. At presentation, extrauterine pelvic extension, most commonly involving the ovary, is found in up to one-third of patients. Thus, when evaluating an ovarian tumor microscopically consistent with an endometrial stromal tumor, it is important to exclude a prior history of uterine endometrial stromal tumor and to suggest inspection of the uterus, as the latter are far more common.

Preoperative endometrial assessment with either office Pipelle or dilation and curettage (D&C) under anesthesia are limited in the evaluation and correct diagnosis of uterine sarcomas; however, it is the investigation of choice in women who presents with abnormal uterine bleeding. Diagnosis of carcinosarcoma is usually confirmed, or at least suggested, at the time of endometrial assessment, but leiomyosarcomas are rarely diagnosed before hysterectomy. In a series by Bansal et al. [29], invasive tumor was diagnosed in 86 % cases of uterine sarcomas on preoperative endometrial sampling and 64 % out of them had correct histology as compared with final histopathology. However, 70 % of cases in his series were carcinosarcomas with only four leiomyosarcomas, two endometrial sarcomas, and eight other sarcomas diagnosed on final histology. Diagnosis of carcinosarcoma may be missed because endometrial biopsy/curettage does not adequately sample both the epithelial and stromal components of the tumor; however, appropriate preoperative referral is usually made because of the presence of a malignancy, and staging is accomplished at the time of hysterectomy. Conversely, most leiomyosarcomas are diagnosed after hysterectomy at the time of histological review of the surgical specimen. This has been highlighted in a GOG study reported by Major et al. [30] where fewer patients with leiomyosarcoma were referred to a higher centre than those with carcinosarcoma (301 carcinosarcomas, 59 leiomyosarcomas, and 93 endometrial stromal sarcomas).