Figure 2.
Morphologic and immunophenotypic patterns of differentiation in individual patients. (A) Monocytic differentiation of leukemic cells. At diagnosis, blasts in this patient were small to intermediate in size with round nuclei and small amounts of cytoplasm and were negative for monocytic markers (CD11b, CD14, and CD64) by flow cytometry. At day 14 postinduction, leukemic cells showed morphologic findings characteristic of monoblasts/promonocytes, with increased cell size, folded nuclei, and increased cytoplasm with cytoplasmic vacuolization. Flow cytometry showed expression of CD11b, CD14, and CD64, as well as increased expression of CD33, consistent with monocytic differentiation. (B-C) Granulocytic differentiation of leukemic cells. (B) At diagnosis, blasts in this patient were small to intermediate in size with round nuclei and small amounts of cytoplasm without prominent cytoplasmic granulation. (C) At day 14, many cells (35% by manual differential) were larger in size with increased cytoplasm and prominent azurophilic cytoplasmic granules (arrow). Also present were blasts (12.5% by manual differential) that resembled those seen at diagnosis (arrowhead). A BM biopsy performed on day 30 postinduction (not shown) showed a normal BM aspirate differential count with 0% myeloblasts. (D) Day 21 aspirate smear from a patient showing both monocytic differentiation, with large cells with folded nuclei and abundant cytoplasm (block arrow) as well as granulocytic differentiation, with cells showing prominent cytoplasmic granulation (arrow). (E-G) A case with delayed differentiation, apparent at day 21. (E) At diagnosis, blasts were intermediate in size with oval nuclei, multiple distinct nucleoli, and small amounts of cytoplasm. (F) At day 14, blasts showed similar morphologic features, without evidence of differentiation. (G) At day 21, blasts showed increased size, more abundant cytoplasm, and prominent cytoplasmic granulation. (H) A patient with persistent AML, without evidence of differentiation. Blasts showed similar morphologic features at all timepoints. (A-H) Wright stain, original magnification ×1000; acquired on an Olympus BX53 microscope with an Olympus DP73 camera, using Olympus cellSens standard software. APC, allophycocyanin; Dx, diagnosis; PE, phycoerythrin; PerCP, peridinin-chlorophyll protein complex; SSC-A, side scatter–area.

Morphologic and immunophenotypic patterns of differentiation in individual patients. (A) Monocytic differentiation of leukemic cells. At diagnosis, blasts in this patient were small to intermediate in size with round nuclei and small amounts of cytoplasm and were negative for monocytic markers (CD11b, CD14, and CD64) by flow cytometry. At day 14 postinduction, leukemic cells showed morphologic findings characteristic of monoblasts/promonocytes, with increased cell size, folded nuclei, and increased cytoplasm with cytoplasmic vacuolization. Flow cytometry showed expression of CD11b, CD14, and CD64, as well as increased expression of CD33, consistent with monocytic differentiation. (B-C) Granulocytic differentiation of leukemic cells. (B) At diagnosis, blasts in this patient were small to intermediate in size with round nuclei and small amounts of cytoplasm without prominent cytoplasmic granulation. (C) At day 14, many cells (35% by manual differential) were larger in size with increased cytoplasm and prominent azurophilic cytoplasmic granules (arrow). Also present were blasts (12.5% by manual differential) that resembled those seen at diagnosis (arrowhead). A BM biopsy performed on day 30 postinduction (not shown) showed a normal BM aspirate differential count with 0% myeloblasts. (D) Day 21 aspirate smear from a patient showing both monocytic differentiation, with large cells with folded nuclei and abundant cytoplasm (block arrow) as well as granulocytic differentiation, with cells showing prominent cytoplasmic granulation (arrow). (E-G) A case with delayed differentiation, apparent at day 21. (E) At diagnosis, blasts were intermediate in size with oval nuclei, multiple distinct nucleoli, and small amounts of cytoplasm. (F) At day 14, blasts showed similar morphologic features, without evidence of differentiation. (G) At day 21, blasts showed increased size, more abundant cytoplasm, and prominent cytoplasmic granulation. (H) A patient with persistent AML, without evidence of differentiation. Blasts showed similar morphologic features at all timepoints. (A-H) Wright stain, original magnification ×1000; acquired on an Olympus BX53 microscope with an Olympus DP73 camera, using Olympus cellSens standard software. APC, allophycocyanin; Dx, diagnosis; PE, phycoerythrin; PerCP, peridinin-chlorophyll protein complex; SSC-A, side scatter–area.

Close Modal
This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal