Copanlisib-Associated Skin Toxicity: A Peculiar Case of Copanlisib-Induced Skin Rash in a Patient with Refractory Follicular Lymphoma

Background: Phosphatidylinositol 3-kinase (PI3K) is an essential target in lymphoid tumors therapy. Copanlisib is a novel class of medication that targets PI3K and used for the treatment of relapsing or refractory B-cell lymphomas. Case Presentation: A 42-year-old woman presents to our hospital for worsening abdominal pain. Examination pertinent for axillary lymphadenopathy, and abdominal ascites. CT chest, abdomen and pelvis reported multiple lung nodules, pleural effusions, extensive retroperitoneal lymphadenopathy, and peritoneal carcinomatosis. Lymph node and bone marrow biopsies confirmed B-cell follicular lymphoma and fluorescent in situ hybridization (FISH) testing was positive for translocation t(14:18). Her disease was refractory to multiple chemotherapy regimens. Thus, initiated copanlisib therapy with a remarkable response, but the patient developed a diffuse maculopapular rash and skin biopsy-proven to be drug rash. Therefore, copanlisib was discontinued. Conclusion: Here, we report a case of a middle-aged woman who developed a rash after the fifth cycle of copanlisib therapy. This case report will create awareness of evolving possible side effects in this novel chemotherapeutic agent.