Clear cell adenocarcinoma arising from a giant cystic adenomyosis: a case report with immunohistochemical analysis of laminin-5 gamma2 chain and p53 overexpression.

We report a case of a clear cell adenocarcinoma arising from a giant cystic adenomyosis, with immunohistochemical analysis of p53 and laminin-5 gamma2 chain overexpression. Microscopically, not only clear cell adenocarcinoma showing myometrial invasion but also single-layered clear cell adenocarcinoma cells lining the cyst wall were observed. Transition from these single-layered tumor cells to papillary proliferative lesions of various degrees was recognized. Moreover, these tumor cells were continuous with minimal atypical cells. Although the tumor cells within the uterus showed a low positive cell ratio for p53, the metastatic foci showed a remarkable p53 overexpression. Laminin-5 gamma2 chain expression was low in papillary proliferation and high in myometrial invasion and metastatic foci. The single-layered tumor cells showing non-invasive proliferation also contained laminin-5 gamma2 chain-positive cells. When non-invasive tumor cells were considered to be at an early stage in tumor progression, some tumor cells had already acquired an invasive feature. p53 overexpression was not related to expression of the laminin-5 gamma2 chain.