Blastic plasmacytoid dendritic cell neoplasm: challenges in diagnosis and treatment with potential of venetoclax as an alternative to vincristine in high-risk patients—a case report

Abstract

Abstract Background Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and challenging cancer for diagnosis and treatment. Accurate diagnosis plays a crucial role guiding appropriate treatment, typically involving high-intensity lymphoblastic leukemia regimens which typically include vincristine. However, the use of vincristine may be particularly limited in patients with pre-existing neuropathy or individuals at high risk of developing it. Here, we present a case of BPDCN that was initially diagnosed as marginal zone lymphoma (MZL) and subsequently as non-specific T-cell lymphoma, thus highlights the importance of accurate diagnosis and modified treatment. Case presentation A 49-year-old Arab man with a medical history of diabetes, peripheral neuropathy, hypertension, and depression presented with widespread, painless multiple skin lesions. After undergoing a biopsy at another institution, the patient was initially diagnosed with MZL, and received two cycles of bendamustine and rituximab. However, the disease relapsed and was later diagnosed with non-specific T-cell lymphoma, which proved refractory to a single cycle of CHOP chemotherapy. The patient was subsequently referred to our centre, where a comprehensive evaluation revealed BPDCN with a unique finding on bone marrow exam: signet ring plasmacytoid dendritic cells. Due to the patient's pre-existing neuropathy and previous treatment, we administered the Hyper-CVAD regimen with a 50% reduction in vincristine dosage, which resulted in an excellent response. During the second part of cycle one, when new skin lesions started appearing, venetoclax was added to the treatment regimen. Subsequently, we discontinued vincristine due to worsening neuropathic pain and neuropathy-related weakness. Venetoclax was continued in cycle two and led to a complete response. The patient achieved a disease-free state for the first time in disease course, maintaining it for a period of over six weeks before experiencing a relapse. Conclusions Accurate diagnosis is crucial for guiding appropriate treatment. Our case highlights the challenges associated with diagnosis and treatment, as well as the potential of venetoclax as an alternative to vincristine, particularly in patients with pre-existing neuropathy or those at a high risk of developing it. Further research is needed to evaluate the effectiveness of BCL2 inhibitors as a replacement for essential drugs and its potential as a bridging therapy until patients can undergo a stem cell transplant.