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.

Sorafenib is a multi-kinase inhibitor approved for the treatment of renal cell and hepatocellular carcinoma. Adverse cutaneous reactions are a very common side effect of the medication. We report the development of hidradenitis suppurativa (HS) in a patient after initiation of treatment with sorafenib. HS is marked by recurrent deep painful nodules, fluctuant abscesses, and draining sinus tracts most frequently occurring in the groin and axilla. To our knowledge, sorafenib-induced HS in the axillary and inguinal skin folds has not been previously reported.