Post-chemotherapy Changes in Bone Marrow in Acute Leukemia With Emphasis on Detection of Residual Disease by Immunohistochemistry

Abstract

Introduction In acute leukemia, the leading cause of treatment failure is disease relapse leading to a low level of complete remission and short overall survival. Post-chemotherapy marrow examination gives vital clues regarding treatment response and marrow regeneration. Aim We aimed to study the histomorphological changes in post-chemotherapy bone marrow in acute leukemias, monitor residual disease by immunohistochemistry (IHC) on trephine biopsy, and correlate survival status. Method This study was a prospective clinical study. A total of 155 post-induction cases (acute myeloid leukemia [AML] - 68 and acute lymphoblastic leukemia [ALL] - 87), from January 2014 to December 2015, were included with a follow-up of 4-28 months. A detailed histomorphology was studied in all cases. IHC was applied in 88 cases of post-induction marrow, which showed morphologic suspicion of an increase in blasts. Observations Post-induction marrow was hypercellular in 55.9% of AML and normocellular in 56.3% of ALL. Regenerative hematopoiesis was noted in 37.4% of AML and 88.5% of cases of ALL. Marrow serous atrophy and stromal edema were associated with delayed recovery of counts and their recovery duration ranged from one to five months. Twenty-seven bone marrow aspirates were unsatisfactory, and their trephine biopsies were showed remission in 20 cases and stromal changes in nine cases. In addition, trephine biopsy picked up residual leukemic blasts in four cases in which aspirate showed remission status. Post-induction marrow IHC with scattered positivity for blasts showed sustained remission in 96% cases, and in those with clustered positivity, 28.6% showed residual disease, and 7.2% showed relapse at the end of the study period. The median survival duration was 13, 3, and 12 months for cases with sustained remission, residual disease, and relapse, respectively. There was a statistically significant difference in median survival of patients in the three groups (sustained remission, residual disease, and relapse) (p=0.000). Conclusion We conclude that histomorphology augmented by IHC on trephine biopsy gives valuable information regarding post-chemotherapy changes and residual disease status. Bone marrow trephine biopsy is an important tool to assess the remission status of patients with acute leukemia.

Keywords: acute leukemia; bone marrow regeneration; dyspoiesis; histomorphology of bone marrow; post-induction chemotherapy; remission; residual disease; serous atrophy; stromal changes; trephine biopsy.

Figure 1. Post-induction marrow histomorphological features

(a) Case of AML, post-induction day 28 bone marrow biopsy showing hypercellularity with regenerating hematopoiesis (H&E, 400x). (b) Case of ALL, post-induction day 28 bone marrow aspirate showing dyserythropoiesis - in the form of nuclear budding (yellow arrow), binucleate form (red arrow), and karyorrhexis (green arrows) (Leishman stain, 400x), inset shows megaloblastic erythroid colonies (Leishman stain, 400x). (c) Case of ALL, post-induction day 29 bone marrow biopsy showing dysmegakaryopoiesis- clustering of megakaryocytes and small hypolobated forms (H&E, 400x). (d) Case of ALL, post-induction day 28 bone marrow biopsy showing serous atrophy change (H&E, 400x). Inset highlight the serous atrophy in the AB PAS stain at pH 2.5 (AB PAS at pH 2.5, 400x).

Figure 2. Post-induction bone marrow stromal changes

(a) Case of ALL, post-induction day 28 bone marrow biopsy showing marrow fibrosis (H&E, 400x). Insets showing the marrow fibrosis highlighted by Masson trichrome stain (400x). (b) Case of AML post-induction day 19 bone marrow biopsy showing stromal edema (H&E, 1,000x). (c) Case of AML post-induction bone marrow biopsy showing marrow necrosis (H&E, 100x). (d) Case of AML post-induction bone marrow biopsy showing increased hemosiderin-laden macrophages (H&E, 1,000x). Inset showing these macrophages are highlighted by Perls’ stain (Perls’ stain, 400x).

Figure 3. Patient’s disease status at the end of the study period (AML)

Figure 4. Patient’s disease status at the end of the study period (ALL)

Figure 5. Post-induction marrow immunohistochemical features

(a) Post-induction bone marrow biopsy showing scattered and small cluster (two to three cells/cluster) (arrow) of large cells (H&E, 400x). (b) These cells were scattered positivity for CD34 (IHC, 400x). (c) Post-induction bone marrow showing clusters of large cells (H&E, 400x). (d) These cells were clustered positivity for CD34 (IHC, 400x).

Figure 6. Median survival duration of post-induction categories in relation to final marrow status