PMC3193611_01
(a) Bone marrow biopsy showing more than 90% cellularity. There is partial replacement of normal marrow with blasts (H and E, x100); (b) The blasts have scant to moderate cytoplasm with prominent nucleoli (H and E, x400); (c) Occasional multinucleated dysplastic megakaryocyte was also noted (arrow) (H and E, x400); (d) Blasts showing strong cytoplasmic positivity CD 61, IHC (x400):
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F1
On immunohistochemistry, the blasts were negative for myeloperoxidase (1:150 dilution, 59A5 clone, Novocastra, New Castle, United Kingdom) and leukocyte common antigen (1:100 dilution, Rp2/18 and Rp2/22 clone, Novocastra, New Castle, United Kingdom), but positive for CD 61 (1:100 dilution, 2f2 clone, Novocastra, New Castle, United Kingdom) [Figures 1a-d].
(a) Blasts varying in size from medium to large, having scant to moderate granular cytoplasm, fine nuclear chromatin and single to multiple prominent nucleoli. Occasional larger cells, having abundant cytoplasm and lobated nuclei (arrow) Papanicolaou (x200); (b) Anucleate pale blue shredded cytoplasmic fragments in the background demonstrated better in low cellularity areas MGG (x400); (c) Blasts immunopositive for CD 61 ICC (x400); (d) Bi and multinucleate forms on cytocentrifuge preparation of the CSF specimen; (inset) binucleate cell mimicking megakaryocyte MGG (x400)
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F2
Some of the blasts had a notch in the nuclear membrane; many had nuclear indentations and folds [Figure 2a]. In addition, many anucleate pale blue staining masses were seen in the background, possibly representing shredded and clumped cytoplasmic fragments or giant platelets [Figure 2b]. Immunocytochemistry showed the blasts to be negative for MPO, but positive for CD61 and CD34 (1:100 dilution, QBEnd 10 clone, Dako, Glostrup, Denmark), thus confirming the diagnosis of extramedullary leukemic deposit of AML M7 [Figure 2c]. There were binucleate forms (micromegakaryocytes) and multinucleate forms (immature megakaryocytes) [Figure 2d]. The patient was treated with three cycles of daunorubicin and cytarabin.
(a) Large cell with moderate amount of granular cytoplasm and a single nucleus showing multiple lobations Papanicolaou (x400); (b) Cell having horse shoe shaped nucleus and dusky cytoplasm MGG (x400); (c) Another cell showing nuclear indentation and early lobulation MGG (x400); (d,e,f) Multinucleated cells with abundant cytoplasm and nuclear lobations resembling immature megakaryocytes MGG (x400)
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F3
There were cells which had single nucleus, but with the nucleus showing lobations, indentations and folds, some being horseshoe shaped [Figures 3a-c]. Bi to multinucleated cells reminiscent of megakaryocytes were also noted [Figures 3d-f].