Benign lymphangioendothelioma (BLAE) (also known as acquired progressive lymphangioma) is an uncommon vascular tumor that is of importance primarily because it can be confused histologically with Kaposi sarcoma (KS) or angiosarcoma.[1, 2] Jones et al first described the tumor as acquired progressive lymphangioma and later as benign lymphangioendothelioma.[3]
Benign lymphangioendothelioma is a proliferation of lymphatic endothelial cells that stain positively for CD31, CD34, podoplanin (D2-40, a lymphatic marker), LYVE-1, and PORX-1.[4, 5] Benign lymphangioendothelioma is not associated with preexisting vascular malformations or lymphedema. Although the lesion rarely is identified during infancy, some suggest it is a hamartoma that first becomes apparent during adolescence or young adult life; the development of benign lymphangioendothelioma is possibly triggered by hormonal changes.
In most instances, the cause is unknown. Trauma has often been blamed,[6] but a reliable connection has never been established. A reactive process versus tumoral etiology is suggested in some literature.[7] In one patient, femoral arteriography was proposed to be a trigger.[8] One case has been reported in association with HIV/AIDS.[9]
Benign lymphangioendothelioma is rare; fewer than 30 cases have been reported.
No racial predisposition is reported.
Males and females are affected equally.
Benign lymphangioendothelioma can affect patients ranging from age 17-90 years (median age 54 y).[1]
Inform patients they have a rare (though benign) vascular tumor that is poorly understood, and annual screening is recommended.
A single, asymptomatic, slowly expanding patch, plaque, or nodule usually manifests during adolescence or young adulthood.[10] Congenital lesions have been reported. A single example of a giant variant has also been described.[11]
Flat to slightly elevated, slowly expanding, red-brown lesions that resemble a bruise may be observed. Occasionally, a red-brown dermal nodule or a skin-colored subcutaneous mass may be observed, either within the patch or alone (see the image below).[12, 13]
 View Image | Erythematous nodule with macular component at the periphery. |
No laboratory studies are necessary for the diagnosis of benign lymphangioendothelioma (BLAE).
Imaging studies usually are not helpful in diagnosing flat lesions. Because the tumor is so uncommon, suggesting an appropriate imaging modality is difficult.
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).
View Image | Overview of a histologic section from a tumor depicting dilated vascular spaces interspersed between collagen fibers and a more central accumulation o.... |
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).
View Image | 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.
View Image | High-power view showing lymphatic endothelial cells in a hematoxylin and eosin–stained section. |
View Image | High-power view showing lymphatic endothelial cells stained positively with podoplanin. |
Once the diagnosis is established, no treatment is necessary. Solitary nodules can be excised; occasionally, local recurrence is observed. If more extensive patches and plaques are cosmetically disturbing but too large to excise, they can be treated with a laser. However, because benign lymphangioendothelioma is relatively free of blood, the usual absorption characteristics that are importance in hemangiomas and vascular malformations are less important, and an individually tailored approach with test areas is recommended.
Because of the rarity of BLAE, many dermatopathologists or surgical pathologists may seek additional evaluation of the specimen from other pathologists. Additionally, appropriate consultations as necessary for surgical treatment.
Complications are usually only those associated with surgery and laser treatment, such as scarring and pigmentary change.
Because of the histologic confusion at times between BLAE, angiosarcoma, and Kaposi sarcoma, annual follow-up to assess for recurrence is recommended.
As this is a rare condition, no specific medical therapy has been shown to be reliably effective. Systemic corticosteroids were reported to be effective in one case.
Erythematous nodule with macular component at the periphery.
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.
High-power view showing dilated vascular channel with innocent endothelial cells.
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.
Erythematous nodule with macular component at the periphery.
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.
High-power view showing dilated vascular channel with innocent endothelial cells.
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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