Discussion
The mechanisms underlying the annular appearance of LC remain unknown; however, an immune reaction against tumor cells may be associated with this phenotype. Previous cases of the skin metastasis of breast cancer showed annular erythema4-6. The underlying mechanisms have been explained as follows: i) tumor cell embolization into the blood and lymph vessels result in local blood congestion and edema, leading to patches of homogeneous erythema centered around emboli; ii) emboli consisting of tumor cells are attacked by cytotoxic T-cells and emboli resolve; iii) blood congestion and edema are sequentially released from the center to the edge of erythema, resulting in the development of the annular appearance of erythema. In the present case, blinatumomab, which may cause an immune reaction against tumor cells, was administered. Immunosuppression may have been induced by the rapid decrease in cytotoxic T-cells immediately after the initiation of the 4th course, leading to tumor cell embolization and the development of patches of homogeneous erythema as LC. Immediately after this condition, the number of anti-tumor cytotoxic T-cells may have increased and these cells may have attacked tumor emboli located in the center of LC, resulting in the annular appearance of erythema temporally.
The present case provides evidence to support the potential involvement of immune-modulating drugs in the phenotype of annular erythema through cytotoxic T-cell reactions against tumor cells. Oncologists and dermatologists need to consider characteristic cutaneous adverse events, particularly in patients treated with immune-modulating drugs.
Acknowledgment: None
Statement of Ethics: The study protocol was approved by The Ethics Committee of The Jikei University School of Medicine and the patient provided written informed consent.
Consent statement: Written informed consent was obtained from the patient to publish this report in accordance with the journal’s patient consent policy.
Data Availability Statement: Additional data sharing is not applicable to this article due to ethical restrictions.