The aim of our review was to identify the current information with regard to the pathogenesis and malignant transformation of adenomyosis. The current literature was reviewed by searching MEDLINE/PubMed, using the following keywords: adenomyosis, myometrium, stromal cells, malignant transformation, pathogenesis, etiology, genome-wide and microarray. Early signs of the development of adenomyosis are considered to be the penetration of stromal cells into the inner layer of the myometrium. Adenomyosis smooth muscle cells are developed, possibly, through a remodeling pathway via reactivation of coelomic epithelial cells as a result of estrogen-induced epithelial mesenchymal transition. Smooth muscle cell hyperplasia and hypertrophy are a reflection of a reaction of the surrounding tissue. The development of adenocarcinoma arising from adenomyosis is a relatively rare occurrence. In our literature review, to date, 44 cases of malignant tumors arising from adenomyosis have been documented. Studies reporting results of genetic abnormalities, epigenetic changes, monoclonal expansion, mutational analysis and the inactivation of specific tumor suppressor genes are very few in this field. In conclusion, adenomyosis can be a precursor of some carcinomas. The exact molecular mechanisms that lead to the malignant transformation are poorly understood.