CORRESPONDENCE AND CORRECTIONS Granular Acute Lymphoblastic Leukemia with Hybrid Phenotype myeloperoxidase (EM-MPO). Rough endoplasmic reticulum, perinuclear space, Golgi apparatus, clusters of microvesicles, and membranous structures were stained positively with EM-MPO. The cytochemical findings suggested the myeloid nature of the blast cells. Nevertheless, at the same time, the blast cells tested positive for CD 10, CD20, CD38, and terminal deoxynucleotidyl transferase. Furthermore, immunoglobulin gene analysis showed rearranged patterns of JH and JK genes. Immunophenotype and genotype indicated the early B-lymphocyte nature of the blast cells. Considering immunophenotype, genotype, cytochemical features, and electron microscopic findings, this case was diagnosed as hybrid acute leukemia sharing characteristics of both early B-lymphocytes and basophils.2 In this regard, Cerezo and colleagues' also suggested the possibility of mixed-lineage leukemia in some of the granular ALLs. In addition to the case presented, we have experienced several cases of leukemia, including ALL, CML-LC, and AML with similar cytoplasmic inclusions; however, the inclusions were negative for MPO as well as EM-MPO in most cases studied.5 Based on the cytochemical results of the inclusions, it is apparent that the inclusions consisted of acid mucopolysaccharides similar to basophil granules. It is still difficult to explain why such granules appear in various types of ALL and CMLLC; aberrant basophilic differentiation may occur during the development of such types of leukemia. Thus, the possibility of hybrid leukemia should be considered when granular ALL has been sus-
pected. Electron microscopic investigations, particularly EM-MPO, are requisite for the correct diagnosis.
of apparent ALL, the presence of granules may indicate a component of myeloid (basophilic) differentiation (either AMLL or acute myeloblasts leukemia [AML]), requiring electron microscopy (EM) for accurate diagnosis. Their case is complicated by an unusual EM morphologic appearance of the granules, which is not typical of usual basophil granules, and the appearance of ultrastructural myeloper-
oxidase only at relapse. Serial cytogenetic studies were not available, and there was incomplete information to determine conclusively whether the relapse process represents simple recurrence or clonal evolution of the original leukemia. Nevertheless, the case is interesting in light of a recent report of eight cases of AML with basophilic differentiation in this journal by Peterson and associates,2 with accom-
NOBUO TAKEMORI, NAGAHITO SAITO,
M.D. M.D.
NORIKO TACHIBANA, KATSUYUKI HIRAI, RYUICHI ONODERA, MASAYOSHI NAMIKI,
M.D. M.D. M.D. M.D.
Third Department of Internal Medicine Asahikawa Medical College Nishikagura Asahikawa, Japan REFERENCES 1. Cerezo L, Shuster JJ, Pullen DJ, et al. Laboratory correlates and prognostic significance of granular acute lymphoblastic leukemia in children: A Pediatric Oncology Group Study. Am J Clin Pathol 1991;95:526-531. 2. Takemori N, Saito N, Tachibana N, et al. Peculiar hybrid leukemia with basophil granule-like inclusions: Light and electron microscopic study. J Clin Electron Microsc 1987;20:295-317. 3. Kobayasi T, Asboe-Hansen G. Ruthenium red staining of ultrathin sections of human mast-cell granules. J Microsc 1971;93:55-60. 4. Parkin JL, McKenna RW, Brunning RD. Ultrastructural features of basophil and mast cell granulopoiesis in blastic phase Philadelphia chromosome-positive leukemia. J Natl Cancer Inst 1980;65:535546. 5. Takemori N, Saito N, Tachibana N, et al. Cytoplasmic inclusions resembling basophil/mast cell granules in leukemic cells: Light and electron microscopic study. In: Miyazaki T ed. New Aspects in Hematology, Volume 19. Hokkaido University Medical Library Series. Sapporo, Japan: Hokkaido University School of Medicine, 1986, pp 119-138.
The Authors' Reply To the Editor:—In the accompanying letter and a previous article' Takemori and colleagues reported a case of acute lymphoblastic leukemia (ALL) with cytoplasmic granular inclusions on light microscopic, cytochemical, and ultrastructural studies suggesting basophilic differentiation and features at relapse to indicate acute mixed-lineage leukemia (AMLL). They suggest that in some cases
156
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
To the Editor:—We read with great interest the article of Cerezo and colleagues' about granular acute lymphoblastic leukemia (ALL) in children. We previously reported a case of a 19-year-old woman with peculiar acute leukemia with basophil granule-like inclusions.2 The blast cells in this case had abundant cytoplasmic inclusions (i.e., granules) that were stained with methanol-based methylene blue and toluidine blue with distinctive metachromasia and that varied in shape with rounded, oval, or doughnutshaped forms surrounded by halos. The findings of the blast cells as well as the inclusions resembled those of granular ALL. When examined with the electron microscope, the inclusions appeared to be cytoplasmic vacuoles that contained some clusters of microvesicles and membranous structures. Furthermore, all of the cytoplasmic vacuoles could be stained with ruthenium red3 at the electron microscopic level. Stainability of the inclusions for both methanol-based basic dyes and ruthenium red indicated that the inclusions consisted primarily of acid mucopolysaccharides; that is, the inclusions resembled basophil granules in content. Based on ruthenium red stainability and ultrastructural features," some investigators have regarded the complex of clusters of microvesicles and membranous structures seen in Philadelphia-positive ALL and chronic myeloid leukemia in lymphoid crisis (CML-LC) as basophil/mast cell granules. In the case presented, some of the blast cells seen in the subsequent relapse revealed apparent positivity for Sudan black B and electron microscopic
pected. Electron microscopic investigations, particularly EM-MPO, are requisite for the correct diagnosis.
of apparent ALL, the presence of granules may indicate a component of myeloid (basophilic) differentiation (either AMLL or acute myeloblasts leukemia [AML]), requiring electron microscopy (EM) for accurate diagnosis. Their case is complicated by an unusual EM morphologic appearance of the granules, which is not typical of usual basophil granules, and the appearance of ultrastructural myeloper-
oxidase only at relapse. Serial cytogenetic studies were not available, and there was incomplete information to determine conclusively whether the relapse process represents simple recurrence or clonal evolution of the original leukemia. Nevertheless, the case is interesting in light of a recent report of eight cases of AML with basophilic differentiation in this journal by Peterson and associates,2 with accom-
NOBUO TAKEMORI, NAGAHITO SAITO,
M.D. M.D.
NORIKO TACHIBANA, KATSUYUKI HIRAI, RYUICHI ONODERA, MASAYOSHI NAMIKI,
M.D. M.D. M.D. M.D.
Third Department of Internal Medicine Asahikawa Medical College Nishikagura Asahikawa, Japan REFERENCES 1. Cerezo L, Shuster JJ, Pullen DJ, et al. Laboratory correlates and prognostic significance of granular acute lymphoblastic leukemia in children: A Pediatric Oncology Group Study. Am J Clin Pathol 1991;95:526-531. 2. Takemori N, Saito N, Tachibana N, et al. Peculiar hybrid leukemia with basophil granule-like inclusions: Light and electron microscopic study. J Clin Electron Microsc 1987;20:295-317. 3. Kobayasi T, Asboe-Hansen G. Ruthenium red staining of ultrathin sections of human mast-cell granules. J Microsc 1971;93:55-60. 4. Parkin JL, McKenna RW, Brunning RD. Ultrastructural features of basophil and mast cell granulopoiesis in blastic phase Philadelphia chromosome-positive leukemia. J Natl Cancer Inst 1980;65:535546. 5. Takemori N, Saito N, Tachibana N, et al. Cytoplasmic inclusions resembling basophil/mast cell granules in leukemic cells: Light and electron microscopic study. In: Miyazaki T ed. New Aspects in Hematology, Volume 19. Hokkaido University Medical Library Series. Sapporo, Japan: Hokkaido University School of Medicine, 1986, pp 119-138.
The Authors' Reply To the Editor:—In the accompanying letter and a previous article' Takemori and colleagues reported a case of acute lymphoblastic leukemia (ALL) with cytoplasmic granular inclusions on light microscopic, cytochemical, and ultrastructural studies suggesting basophilic differentiation and features at relapse to indicate acute mixed-lineage leukemia (AMLL). They suggest that in some cases
156
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
To the Editor:—We read with great interest the article of Cerezo and colleagues' about granular acute lymphoblastic leukemia (ALL) in children. We previously reported a case of a 19-year-old woman with peculiar acute leukemia with basophil granule-like inclusions.2 The blast cells in this case had abundant cytoplasmic inclusions (i.e., granules) that were stained with methanol-based methylene blue and toluidine blue with distinctive metachromasia and that varied in shape with rounded, oval, or doughnutshaped forms surrounded by halos. The findings of the blast cells as well as the inclusions resembled those of granular ALL. When examined with the electron microscope, the inclusions appeared to be cytoplasmic vacuoles that contained some clusters of microvesicles and membranous structures. Furthermore, all of the cytoplasmic vacuoles could be stained with ruthenium red3 at the electron microscopic level. Stainability of the inclusions for both methanol-based basic dyes and ruthenium red indicated that the inclusions consisted primarily of acid mucopolysaccharides; that is, the inclusions resembled basophil granules in content. Based on ruthenium red stainability and ultrastructural features," some investigators have regarded the complex of clusters of microvesicles and membranous structures seen in Philadelphia-positive ALL and chronic myeloid leukemia in lymphoid crisis (CML-LC) as basophil/mast cell granules. In the case presented, some of the blast cells seen in the subsequent relapse revealed apparent positivity for Sudan black B and electron microscopic
