Similar histologic features and immunohistochemical staining in microcystic and macrocystic lymphatic malformations

Background: Lymphatic malformations are benign but potentially life-threatening lesions mostly found in the head and neck. They can be classified into two types: microcystic and macrocystic. Microcystic lesions are more difficult to treat. In this study, we describe the histologic features and expression of lymphatic endothelial markers in microcystic and macrocystic lymphatic malformations and correlate clinical data with histologic and immunohistochemical data. Methods and Results: This is a retrospective study of clinical data and tissue specimens which were collected from 18 children who underwent surgical excision of lymphatic malformations. The clinical data were analyzed with descriptive statistics. Microcystic and macrocystic lesion specimens were examined with Movat pentachromic stain and immunohistochemistry for lymphatic endothelial markers. Patients with microcystic lesions were more likely to have mucosal involvement, recurrence, and higher stages of disease, compared with those with macrocystic lesions. Microcystic and macrocystic lesions stained similarly with Movat pentachromic stain and for lymphatic endothelial cell markers. Conclusions: Although microcystic and macrocystic lesions have different clinical behavior, they have indistinguishable histological features and immunohistochemical staining for markers of lymphatic endothelium. These findings suggest that both microcystic and macrocystic lesions are derived from similar tissue but may behave differently based on their anatomic microenvironment.