Uterine precursor lesions in patients with incidental nodal lymphangioleiomyomatosis: A report of 4 cases

Uterine sections from 6 patients with incidental nodal lymphangioleiomyomatosis (LAM) were examined for LAM lesions by screening these sections with cathepsin K immunohistochemistry (IHC) stains. The hysterectomy specimens were all concurrent with the lymph node dissections in which the nodal LAM was discovered. In 4 of 6 patients microscopic lesions of pre-LAM were identifi ed and confi rmed by IHC staining for HMB-45 and beta-catenin. All lesions were grossly inapparent and also inapparent by routine hematoxylin and eosin stains. Three variants of pre-LAM lesions were identifi ed. None of the pre-LAM lesions had an associated lymphatic proliferation. It is proposed that these pre-LAM lesions gave rise to the incidental nodal LAM lesions. Furthermore, it is suggested that the absence of an associated lymphatic proliferation associated with these lesions may be a factor in the attenuated potential for spread and the only rare association of these nodal lesions with pulmonary LAM. Research Article