Blastic Plasmacytoid Dendritic Cell Neoplasm: Report of Three Cases.

An 80 year-old-man was admitted to our institution on December 2006. He referred the occurrence of skin lesions since January 2005, when a diagnosis of extranodal B-cell non-Hodgkin lymphoma was made and treatment with conventional chemotherapy was performed, but without achieving any response. At our evaluation he presented leukocytosis (144 × 10⁹/L) associated with purplish, firm nodules on the trunk, arms and face. Peripheral blood and bone marrow aspirate showed the presence of blast cells with a lymphoid appearance, granular periodic acid-Schiff (PAS) positivity and a high expression of CD33, CD4, and CD56. He was treated with AML-like therapy, but died of disease progression.

A 79-year old woman was admitted in December 2006 with a 2-month history of anemia, splenomegaly, and weight loss of 10 kg in the last year. Laboratory tests were as follows: Hb, 41 g/L; leukocytes, 2.5 × 10⁹/L (with 10% of blast cells); platelets, 43 × 10⁹/L. No lymphadenopathy or skin lesions were present. Bone marrow examination revealed 41% of small to medium-sized blast cells without Auer rods or granula and negative reactivity to myeloperoxidase, esterase and PAS. She was treated with an AML-like protocol; she achieved partial response, but died after three months, of disease progression.

A 69-year-old man was admitted to our Institution for cytopenia in June 2009. He referred the occurrence of brownish-purple firm nodules on the trunk since April 2009. At our evaluation he presented pancytopenia; bone marrow aspiration was performed and revealed infiltration by 65% of blasts with reticulated chromatin, evident nucleoli, a vacuolated cytoplasm and pseudopodia-like expansions. The blasts were negative for myeloperoxidase, monocyte esterase and PAS staining. Skin biopsy revealed a dermal infiltration by the same blastic-cell BM population. He underwent AML-like therapy and, although the skin lesions disappeared, 30% blastic bone marrow infiltration persisted.

Morphological revision of these cases, selected for their peculiar immunophenotype reported in the following Table, revealed the same cytological features and cytochemical reactivity in cases 2 and 3; case 1 had a lymphoblastic-like morphology and showed PAS positivity, but the lack of cCD3 was not consistent with the diagnosis of ALL. All the cases were FLT3-ITD+. We suggest that a correct modern panel of MoAb with a careful morphological examination could help to pose the diagnosis of BPDCN, which typically affects older patients and is characterized by poor prognosis.

No relevant conflicts of interest to declare.