Diagnosis of a Rare Form of Leukemia at a Glance Thanks to Pathognomonic Skin Lesions
A 77-year-old man presented for investigation of violaceous papules that had suddenly appeared on his chest, abdomen, and back 6 months earlier. The patient displayed B symptoms, was underweight (BMI 18.2 kg/m2), and his blood count showed leukocytosis (29/nL), anemia (Hb 11.8 g/dL), and thrombocytopenia (78/nL). Examination of a biopsy sample revealed medium-sized to large blastic, occasionally plasmacytoid infiltrates that were positive for CD4, CD43, and CD56 and weakly positive for CD123. The Ki-67 proliferation index was elevated (80–90%). We diagnosed blastic plasmacytoid dendritic cell neoplasia, a rare form of myeloid neoplasia that arises from precursors of the plasmacytoid dendritic cells and is often first manifested by the occurrence of cutaneous papules. The prognosis is poor, with mean survival of 12–14 months. Staging revealed the presence of enlarged cervical and mediastinal lymph nodes, and examination of a bone biopsy sample showed infiltration by atypical CD123-positive cells. There were no abnormal findings on fluorescence-activated cell sorting analysis. We prescribed off-label chemotherapy with azacitidine and venetoclax, to which the papules were responding at the time of writing.
Dr. med. Ines Bertlich, Prof. Dr. med. Alexander Enk, Dr. med. Ferdinand Toberer, Hautklinik Universitätsklinikum Heidelberg,
Conflict of interest statement: The authors declare that no conflict of interest exists.
Translated from the original German by Christine Rye.
Cite this as: Bertlich I, Enk A, Toberer F: Diagnosis of a rare form of leukemia at a glance thanks to pathognomonic skin lesions.
Dtsch Arztebl Int 2020; 117: 732. DOI: 10.3238/arztebl.2020.0732