Radiation recall dermatitis in HER 2 positive breast cancer patients triggered by trastuzumab: A rare case report and review of literature.

INTRODUCTION AND IMPORTANCE: Radiation recall dermatitis (RRD) is a localized drug-induced inflammatory skin reaction occurring exclusively in a previously irradiated site months to years after discontinuation of ionizing radiation. The symptoms of RRD can range from mild redness to extensive dermatitis. Antineoplastic drugs such as doxorubicin, docetaxel, paclitaxel, and gemcitabine are most commonly associated with radiation recall reactions. These reactions can also occur with antibiotics and anti-tubercular drugs. CASE PRESENTATION: A 38-years-old woman with hormone receptor-negative, HER2-positive inflammatory breast cancer (right), clinical stage cT4dN1Mx, received neoadjuvant chemotherapy with AC > TH protocol at 3 weeks intervals (Anthracycline-Doxorubicin plus Cyclophosphamide X 4 cycles, then docetaxel plus Trastuzumab X 4 cycles) followed by modified radical mastectomy followed by adjuvant locoregional radiotherapy. She received the 5th cycle and 6th cycle trastuzumab monotherapy just before the start of surgery and radiotherapy, respectively. After 1 month of completion of radiotherapy, during her seventh cycle of Trastuzumab monotherapy, she developed mild edema with erythematous change over the previously irradiated area with fever. A skin biopsy was taken to exclude any recurrence; however, no evidence of malignancy was found. CLINICAL DISCUSSION: We diagnosed it as a case of RRD. We managed her conservatively. Later, she was rechallenged with the same dose in subsequent cycles with systemic steroid coverage, which she tolerated very well, except for the reappearance of mild erythema following each cycle of maintenance dose of Trastuzumab. CONCLUSION: Radiation recall dermatitis is an extremely rare phenomenon; hence, an acquaintance of clinicians with this rare entity is essential for timely diagnosis and appropriate management.

Trastuzumab-induced toxic epidermal necrolysis in a Her-2-positive metastatic breast cancer patient-A rare case report.

Toxic Epidermal Necrolysis (TEN) is a rare, but potentially fatal mucocutaneous reaction, that may occur due to an immunologic response to certain medications. However, TEN triggered by Trastuzumab is extremely rare. Early diagnosis, recognition, and prompt cessation of the offending drugs and initiation of steroid therapy with supportive management are the most important actions for managing TEN. Although rare, it is important to be vigilant about this potential adverse reactions associated with trastuzumab to ensure patient safety and contribute to better outcomes.