Classification of cutaneous intravascular breast cancer metastases based on immunolabeling for blood and lymph vessels.

BACKGROUND: Intravascular breast cancer metastases to the skin can have several clinically distinct manifestations. Carcinoma telangiectoides, which presents as an erythematous patch with prominent telangiectasias or lymphangioma circumscriptum-like lesions, is a rare manifestation of cutaneous metastatic breast cancer and has been proposed to spread via dermal blood vessels. Carcinoma erysipelatoides, which presents as an erysipelas-like patch or plaque, has been proposed to spread via lymphatics. Clinical variants with nodular lesions that show tumor cells within vessels and in the extravascular space are seen more commonly. It has not been demonstrated conclusively whether dermal blood vessels or whether dermal lymph vessels are principally involved in these clinically distinct forms of cutaneous breast cancer metastases. OBJECTIVES: We sought to determine if carcinoma telangiectoides affects predominantly dermal blood vessels and if carcinoma erysipelatoides affects predominantly dermal lymph vessels. METHODS: Serial sections of biopsy specimens from patients with a characteristic clinical presentation of carcinoma telangiectoides and carcinoma erysipelatoides were labeled for cytokeratin to identify malignant cells. Subsequently, these sections were labeled for CD31 (a marker for blood and lymph vessels) and podoplanin (a marker for lymph vessels, but not for blood vessels), to differentiate blood vessels from lymph vessels in these sections. RESULTS: Sections from carcinoma telangiectoides showed malignant tumor cells strictly within dermal blood vessels, but not in lymph vessels. In contrast, sections from carcinoma erysipelatoides showed malignant tumor cells strictly in dermal lymphatics. LIMITATIONS: We used typical clinical cases to demonstrate the distinct involvement of blood and lymph vessels in these variants of cutaneous metastatic breast cancer. A larger case series is needed to confirm these findings. CONCLUSIONS: Immunolabeling for CD31 and podoplanin of cutaneous lesions of metastatic breast cancer confirms the spread of tumor cells predominantly via lymphatics in carcinoma erysipelatoides and predominantly via blood vessels in carcinoma telangiectoides.