Acquired progressive lymphangioma (APL), or benign lymphangioendothelioma, is an unusual entity derived from vascular structures. Clinically and histopathologically it may resemble Kaposi's sarcoma and well-differentiated angiosarcoma, causing a diagnostic problem. We report an individual with APL initially diagnosed with Kaposi's sarcoma who underwent unnecessary laboratory testing. Imiquimod 5% cream stopped the progression of the lesion. Awareness of this rare entity may prevent patients from undergoing excessive testing. Imiquimod may be used as a safe, effective treatment option.