Unilateral psoriasis in a woman with ipsilateral post-mastectomy lymphedema

Psoriasis is a multi-factorial disease with various clinical manifestations. We present a case of unilateral psoriasis associated with ipsilateral lymphedema that developed after mastectomy for breast cancer. A 42-year-old Korean woman was referred to our clinic with a 1-month history of multiple erythematous scaly patches on the right arm, back, and breast and was diagnosed with psoriasis by a skin biopsy. Three years previously, she had been diagnosed with breast cancer (T1N2), underwent a right quadrantectomy and axillary lymph node dissection, and completed adjuvant chemotherapy followed by high-dose adjuvant radiotherapy. She had started rehabilitation therapy on the right arm for secondary lymphedema 30 months previously. Because of the long interval between radiation and psoriasis, we speculated that changes in the local milieu caused by the lymphedema might be a causative factor. We hereby report a rare case of unilateral psoriasis following post-mastectomy lymphedema.