Case report of blastic plasmacytoid dendritic cell neoplasm (BPDCN) a rare entity

Abstract

Aim/Background: BPDCN is a rare aggressive haematological malignancy in the elderly, with high frequency of cutaneous and bone marrow involvement and a poor prognosis. Our aims are (1) to increase awareness of this rare entity and (2) discuss the value of different investigation tools in diagnosis and response assessment.Method: A 75-year-old man presented with widespread nodular violaceous rash. Full blood count showed Hb 112 g/L, WCC 16.5×109/L, platelets 162×109/L and circulating blasts. Skin biopsy, bone marrow biopsy and flow cytometry were consistent with BPDCN (CD4+, CD56+, CD38+, CD45dim, CD123bright, negative for lineage markers). He was commenced on induction chemotherapy using a modified acute lymphoblastic leukaemia (ALL) protocol for the elderly.Results: Chemotherapy was well tolerated with complete resolution of skin lesions by day 15. Repeat bone marrow biopsy (day 30) revealed significant reduction but persistence of blasts (9%) detected by flow cytometry.Conclusions: Ancilliary investigations in particular flow cytometry and immunohistochemistry are essential in the diagnosis of BPDCN and to distinguish this from other haematological malignancies. Bone marrow biopsy together with flow cytometry and/or immunohistochemistry to assess remission status should be considered post induction chemotherapy even if cutaneous manifestations have resolved. Aim/Background: BPDCN is a rare aggressive haematological malignancy in the elderly, with high frequency of cutaneous and bone marrow involvement and a poor prognosis. Our aims are (1) to increase awareness of this rare entity and (2) discuss the value of different investigation tools in diagnosis and response assessment. Method: A 75-year-old man presented with widespread nodular violaceous rash. Full blood count showed Hb 112 g/L, WCC 16.5×109/L, platelets 162×109/L and circulating blasts. Skin biopsy, bone marrow biopsy and flow cytometry were consistent with BPDCN (CD4+, CD56+, CD38+, CD45dim, CD123bright, negative for lineage markers). He was commenced on induction chemotherapy using a modified acute lymphoblastic leukaemia (ALL) protocol for the elderly. Results: Chemotherapy was well tolerated with complete resolution of skin lesions by day 15. Repeat bone marrow biopsy (day 30) revealed significant reduction but persistence of blasts (9%) detected by flow cytometry. Conclusions: Ancilliary investigations in particular flow cytometry and immunohistochemistry are essential in the diagnosis of BPDCN and to distinguish this from other haematological malignancies. Bone marrow biopsy together with flow cytometry and/or immunohistochemistry to assess remission status should be considered post induction chemotherapy even if cutaneous manifestations have resolved.