| Abstract|| |
Granular acute lymphoblastic leukemia (G-ALL) may mimic the diagnosis of acute myeloid leukemia due to the presence of cytoplasmic granules found in the lymphoblasts. This rare variant is commonly seen in children but may occur in adults also. We report a case of G-ALL in an adult female patient.
Keywords: Granular acute lymphoblastic leukemia, leukemia, lymphoblast
|How to cite this article:|
Anand H, Tyagi S. Granular acute lymphoblastic leukemia in an adult patient. Indian J Pathol Microbiol 2008;51:116-7
| Introduction|| |
The presence of azurophilic granules in the blast cells of a leukemia patient is described as a characteristic feature of acute myeloid leukemia, which contains myeloperoxidase and help in differentiating myeloid from lymphoblastic leukemia. Rarely, these intracytoplasmic azurophilic granules may be observed in acute lymphoblastic leukemia and may lead to misdiagnosis.  The clinical significance of granular acute lymphoblastic leukemia (G-ALL) is not known clearly. Granular ALL has been found commonly in children, but sometimes may be observed in adults  . We describe a case of G-ALL.
| Case History|| |
A 30-year-old female presented with pyrexia and loss of appetite for 1 month. General physical examination revealed pallor, hepatomegaly (2 cm), splenomegaly (3 cm) and bilateral cervical lymphadenopathy, which was nontender and 1 x 1 cm in size.
Her hemogram revealed bicytopenia with Hb - 5.4 gm/dl, total leucocyte count (TLC) - 20x10 3 /µl and platelets 20x10 3 /µl.
Peripheral smear stained with May-Grunwald-Giemsa show high TLC with 90% lymphoid blasts. Approximately 22% of these blasts showed coarse intracytoplasmic granules [Figure - 1].
Bone marrow aspirate and imprint smear show cellular aspirate with 94% lymphoblasts of FAB L2 morphology and 6% mature lymphocytes. Intracytoplasmic coarse granules were also observed in 13% of blasts in the bone marrow. On studying the cytochemistry, these granules were negative for myeloperoxidase, Sudan black B, non-specific esterase, specific esterase, acid phosphatase and showed block positivity for periodic acid-Schiff's stain (PAS) [Figure - 2]. Immunophenotyping done on bone marrow aspirate showed CD-10 and CD-19 positivity in the blasts and were negative for CD-13 and CD-33.
| Discussion|| |
One of the main accepted morphological criteria to diagnose acute myeloid leukemia (AML) is the presence of cytoplasmic granules. Granules in the lymphoblasts are a relatively uncommon morphologic finding.
However, granular ALL in children have been reported in large study by Pediatric Oncology Group (POG) Granular ALL was identified in 56 out of the 1252 cases, more commonly in FAB L2 subtype of acute leukemia (4.5%). , Overall frequency of granular ALL ranges from 1.7% to 7% of all ALLs.  According to this study cases with granular ALL were found to have a worse prognosis regardless of other risk factors, immunophenotype or FAB subtype. According to another study performed on children by Aieop Cooperative Group for Cytology of Acute Leukemias, out of 531 cases, 21 cases (4%) had granular blasts and immunophenotype of common ALL;  however, they did not find any prognostic significance of this entity. Another study was performed at St. Jude Children Research Hospital in which 5 out of 66 patients (7%) were found to have granular ALL. 
The index case showed block positivity for PAS and negativity for nonspecific esterase and acid phosphatase. The positivities for nonspecific esterase and acid phosphatase have also been described in the previous studies. 
A single case report of T-cell granular ALL with immunophenotypes of CD-2, CD-3, and CD-7 has also been described.  A rare case of granular acute lymphoblastic leukemia (ALL) in a 45-year-old woman with a history of multiple myeloma has also been reported.  However, its importance and also correlation with FAB subtype remains uncertain. The practical implication of granular lymphoblasts in ALL lies in the fact that it may cause diagnostic confusion with AML.
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Department of Haematology, 1st Floor IRCH Building, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2]