[Myxoid variant of adrenocortical carcinoma]. / Carcinome corticosurrénalien variante myxoïde : aspects clinico-pathologiques et immunohistochimiques d'une variante rare et agressive.

We report two cases of patients presenting myxoid variant of adrenocortical carcinoma (ACC). This very rare variant is characterized by a tumoral proliferation organized in trabeculae, cords or even pseudo-glands within an acellular myxoid materiel stained by Alcian Blue and negative for PAS. Tumor cells have a small to medium size and have little atypia. Their immunohistochemical profil (positivity of Synaptophysin, SF1, Melan A, Vimentin and Inhibin, with a weak or negative pancytokeratin expression) eliminate the main differential diagnoses (metastasis of a myxoid adenocarcinoma and soft tissue myxoid tumor). Many scoring systems have been proposed in order to evaluate the risk of malignancy of these lesions: the Weiss score seems less efficient to evaluate malignancy in this variant than the reticulinic algorithm or the Helsinki score. Prognosis of myxoid variant of ACC seems worse than classical ACC.