Evaluation of the Relationship Between Adenosarcoma and Carcinosarcoma and a Hypothesis of the Histogenesis of Uterine Sarcomas

Abstract

The terminology of uterine sarcomas is confusing and has been inconsistently applied. The relationships among the various types of uterine sarcomas are unknown. To elucidate the relationship between carcinosarcoma (malignant mullerian mixed tumor) and adenosarcoma, a series of 26 consecutive endometrial carcinosarcomas was evaluated for the presence of an adenosarcoma-like component. Four of 26 carcinosarcomas (15%) had an adenosarcoma-like component. The clinical and pathologic features of these tumors were otherwise similar to ordinary endometrial carcinosarcomas. A histogenetic schema for uterine sarcomas is proposed, interrelating endometrial stromal sarcomas, adenosarcomas with and without sarcomatous overgrowth, and poorly differentiated sarcoma not otherwise specified. Although most carcinosarcomas are accepted as being metaplastic or sarcomatoid carcinomas, it is suggested that the carcinomatous component of 8% to 16% of carcinosarcomas arise within, or in the endometrium adjacent to, an adenosarcoma. This latter group is then integrated into the histogenetic schema. Observations based on our data and the limited data in the literature that support this hypothesis include: 13% of endometrial carcinosarcomas have gross and microscopic features of collision tumors, 13% have an adenosarcoma-like component, 16% have a low-grade stroma, and approximately 8% are biclonal indicative of a collision tumor. The most parsimonious interpretation of these data indicates that approximately 8% to 16% of endometrial carcinosarcomas arise because of malignant transformation of the epithelial component within, or in the endometrium adjacent to an adenosarcoma.

A practical approach to the diagnosis of mixed epithelial and mesenchymal tumours of the uterus

“…27 A small percentage of uterine malignancies with a malignant epithelial and mesenchymal component may be true collision tumours (for example, an endometrioid adenocarcinoma admixed with a lowgrade endometrial stromal sarcoma or a leiomyosarcoma) or arise as a result of malignant transformation within the epithelial element of an adenosarcoma (see below). 28 Whether these represent true carcinosarcomas or collision tumours remain not clear.…”

“…The latter is usually a low-grade endometrioid carcinoma. 28 The stromal component, which is typically low grade, is composed of spindled and/or round cells with scant cytoplasm, but rarely can be high grade. Intraglandular protrusions of stroma and the manner in which the stromal cells, which often resemble endometrial stromal cells, concentrate around or beneath the glandular elements ('periglandular cuffing') are characteristic (Figure 8).…”

Role of p53 Pathway Alterations in Uterine Carcinosarcomas (Malignant Mixed Müllerian Tumors)

“…This divergence occurs late during tumorigenesis because a limited number of CSs are collision tumors [53]. It is worth pointing out that approximately 8-16% of all uterine CSs may arise in the endometrium adjacent to an adenosarcoma [54]. …”

Genomic aberrations in carcinomas of the uterine corpus

“…These biphasic or mixed epithelial-mesenchymal tumors were formerly classified among the uterine sarcomas. More recently, however, a consensus seems to have formed that, because of their features, these tumors are best described as metaplastic carcinomas, that is, as primarily epithelial malignant tumors that also contain elements indicative of sarcomatous differentiation (Seidman and Chauhan, 2003).…”