Laboratory Studies
No laboratory studies are necessary for the diagnosis of benign lymphangioendothelioma (BLAE).
Imaging Studies
Imaging studies usually are not helpful in diagnosing flat lesions. Because the tumor is so uncommon, suggesting an appropriate imaging modality is difficult.
Other Tests
No other tests are necessary.
Procedures
Biopsy of the suspect lesion is required for diagnosis.
Histologic Findings
The striking features of benign lymphangioendothelioma are the thin-walled endothelial-lined spaces that are interspersed between strands of collagen. Flat lesions may exhibit only this feature, whereas more nodular lesions may have a central collection of multiple complex vascular spaces (see the image below).
Overview of a histologic section from a tumor depicting dilated vascular spaces interspersed between collagen fibers and a more central accumulation of many complex vascular spaces.
More superficial channels are dilated, whereas at the periphery and deeper, the channels are slitlike. The spaces are usually empty or they may contain proteinaceous material, but they usually do not have abundant red blood cells (see the image below).
High-power view showing dilated vascular channel with innocent endothelial cells.
The endothelial cells are not large or otherwise atypical. Occasionally, a hobnail pattern is seen, suggesting some relationship to targetoid hemosiderotic hemangioma and related tumors. Extravasated red blood cells, hemosiderin, and plasma cells, which are 3 markers for Kaposi sarcoma, are not observed. Less differentiated accumulations of tumor cells are not found.
The endothelial cells stain positively for lymphatic markers such as podoplanin (D2-40), LYVE-1, and PROX-1. Staining for human herpesvirus type 8 is negative, excluding the diagnosis of Kaposi sarcoma. The cells are also variably positive for factor VIII, Ulex europaeus agglutinin I, CD31, and CD34. The staining patterns are too variable to be of diagnostic importance and one should rely primarily on the lymphatic stains. [14, 15] See the images below.
High-power view showing lymphatic endothelial cells in a hematoxylin and eosin–stained section.
High-power view showing lymphatic endothelial cells stained positively with podoplanin.
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Erythematous nodule with macular component at the periphery.
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Overview of a histologic section from a tumor depicting dilated vascular spaces interspersed between collagen fibers and a more central accumulation of many complex vascular spaces.
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High-power view showing dilated vascular channel with innocent endothelial cells.
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High-power view showing lymphatic endothelial cells in a hematoxylin and eosin–stained section.
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High-power view showing lymphatic endothelial cells stained positively with podoplanin.
