Submitting Author: Zhao, Weiqiang (John), MD PhD
Institution: Wexner Medical Center at the Ohio State University
Additional authors:Gerard Lozanski, Arwa Shan'ah, Amy Gewirtz
Session: Extramedullary manifestations of myeloid neoplasms

A 70 yr old male without previous significant medical history until August 2012 developed symptoms of URI and was given a course of antibiotics. Around the same time he noted bloody diarrhea for one day and underwent a colonoscopy without significant findings. He continued to be persistently fatigued and was unable to work. He had 10 lb. weight loss, anemia (WBC 1.9; HGB 7.2; and Platelet 98) and “blasts” in the peripheral blood. Performance status: Karnofsky scale 80 (ECOG grade 1) Performs normal activity with effort.

Left iliac crest bone marrow biopsy (0.2x0.8 cm), aspirate, and peripheral blood smear:

Microscopic examination:

PB smear shows a leukopenia with circulating blasts characterized as medium sized cells with immature chromatin, prominent nucleoli, and minimal cytoplasm. No Auer rods are seen. There is an absolute neutropenia and occasional reactive lymphocytes. There is a marked normocytic anemia with 1+anisocytosis, 1+ ovalocytes, and occasional polychromasia. There is a mild thrombocytopenia with unremarkable morphology.

BM (0.2 x0.8 cm) is hypercellular (90%) with diffuse marrow involvement by a mononuclear cell population and blasts. The blasts were characterized as medium-sized cells with immature chromatin, indistinct nucleoli, and minimal amounts of cytoplasm. No Auer rods are seen. Mild dysplasia (<10%) is noted in the mature granulocytes consisting of nuclear hyposegmentation.

Flow cytometric analysis demonstrates increased blasts (44% of the total events) that express HLA-DR, CD123, CD56, CD7, and cMPO (16%) with a subpopulation with aberrant cCD79a expression (10%).

Cytochemical stain shows the blasts are negative for NSE.

Immunostains on the bone marrow biopsy show these leukemia cells are negative for MPO, granzyme B and CD68, but positive for CD4 and CD43.

46,XY[19]/4n[1]

None.

BPDCN is a very rare (< 100 cases reported) acute leukemia, and less than 100 cases reported word wide. The patient presented with no skin lesion or lymphadenopathy but possible bowel obstruction (diarrhea and blood but negative by colonoscopy). The patient was in remission after the treatment with Decitabine. The current bone marrow biopsy (2 months later) shows 60% cellularity, basts 8%, and platelet 199. Ref: WHO 2008 Classification (Ch6:145-147): AML and Related Precursor Neoplasms

Blastic plasmacytoid dendritic cell neoplasm

Case 346