Hand-foot syndrome (HFS), also known as palmoplantar erythrodysesthesia or acral erythema, is a known adverse effect of chemotherapeutic agents that most commonly presents as palmoplantar dysesthesia and erythematous plaques localized to the palms and soles. Paclitaxel is an uncommon cause of HFS and is notable for its unique presentation on the dorsal hands and feet. We present an unusual case of paclitaxel-induced HFS localized to the dorsal hands of a 66-year-old man with metastatic angiosarcoma. Early identification and management of HFS is critical to allow for continuation of chemotherapy while improving patient quality of life.

The histopathologic characteristics of reactions caused by the many novel anticancer agents are under-recognized. We report a case of a 67-year-old female with locally advanced metastatic breast cancer, who initially presented with an extensive reticulated erythematous patch on the trunk caused by intravascular metastases confirmed by a skin biopsy. Owing to disease progression, she was started on ixabepilone, a mitotic inhibitor. While receiving ixabepilone, another skin biopsy was obtained and initially interpreted as extramammary Paget's disease. However, the biopsy showed metaphase arrest of numerous keratinocytes in the basilar and suprabasilar epidermis. Atypical epithelial cells were only present in the intravascular spaces similar to the initial biopsy. Given the temporal association between the initiation of ixabepilone therapy and the epidermal mitotic arrest, a diagnosis of chemotherapy reaction to ixabepilone was rendered. Ixabepilone is an analog of epothilone, a microtubule stabilizer causing mitotic arrest of the cell cycle approved for the treatment of metastatic and locally advanced treatment-resistant breast cancer. The demonstration of epidermal mitotic arrest caused by ixabepilone is without precedent. The case emphasizes the importance of considering a chemotherapy reaction in the histologic differential diagnosis of epidermal mitotic arrest in a cancer patient receiving chemotherapy.

5-Fluorouracil (5-FU) is an antineoplastic agent that is used topically to treat actinic keratoses. Although topical 5-FU frequently causes irritant contact dermatitis at the site of application, distant skin reactions are rare and could relate to accidental transfer or systemic absorption of the drug. We present a patient who developed a painful scrotal dermatitis after applying the topical cream to actinic keratoses on his chest. Upon discontinuation of topical 5-FU, the reaction resolved over a four-week period with oral prednisone and topical betamethasone ointment. The patient was re-challenged with topical 5-FU one year later and again developed scrotal pain and erythema similar to the initial reaction. Scrotal dermatitis is a rare adverse effect of topical 5-FU therapy that can be associated with significant distress and disruption of daily activities.

Regorafenib is a second-generation multikinase inhibitor that is approved for the treatment of metastatic colon cancer and advanced gastrointestinal stromal tumors. Hand-foot skin reaction, alopecia, and oral mucositis are well-established side effects of this medication. Herein, we discuss a 60-year-old woman who developed a lobular and septal granulomatous panniculitis after six months of therapy with regorafenib. Biopsy demonstrated focal lobular and septal granulomatous inflammation admixed with septal fibrosis and lobular lymphohistiocytic infiltrate associated with fat necrosis. To our knowledge, regorafenib-induced panniculitis has not been previously described. Increased awareness of this presentation can facilitate more timely diagnosis and treatment.