Near-Tetraploid/Tetraploid Acute Myeloid Leukemia: Morphologic, Cytogenetic, and Prognostic Features
Julia S Manny, Timothy Pardee, Mark Pettenati, Changlee S Pang. Wake Forest School of Medicine, Winston-Salem, NC
Background: Numerical and structural abnormalities are common in acute myeloid leukemia (AML), but cases with near-tetraploid/tetraploid (NT/T) are very rare. Subsequently, clinicopathologic features of near-tetraploid/tetraploid AML (NT/T-AML) are not well established. A few reports have documented associations with large blast size and unfavorable prognosis based on complex karyotype. To better characterize this entity, we evaluated cases of NT/T-AML assessing morphologic, cytogenetic, and prognostic findings.
Design: We searched our database for NT/T-AML cases from 1991-2011. Bone marrow aspirates and biopsies were examined and available clinical data was reviewed.
Results: Twelve cases were identified, including 11 men and 1 woman, with a median age of 64 years (43-76). Patients presented with signs and symptoms of bone marrow failure (9/12) or myeloid sarcoma (3/12). Predominately large blasts were seen in 7 cases with the remaining cases exhibiting a range of sizes. Additional morphologic features included cytoplasmic blebbing (7/12), cytoplasmic vacuoles (6/12), nuclear contour irregularities (5/12) and hemophagocytosis (1/12). 8/12 cases were classified as AML with myelodysplasia-related changes, 5 of which had an established diagnosis of a myelodysplastic syndrome. Dysplasia at the time of NT/T-AML diagnosis consisted of dyserythropoiesis (7/12), dysmegakaryopoiesis (4/12) and dysgranulopoiesis (3/12). Multiple cytogenetic abnormalities were frequent (10/12) with only 2 cases exhibiting tetraploidy as the sole abnormality. The most common abnormalities included -7 (5/12), -5/5q (3/12) and -12 (3/12). 4 patients with <3 distinct cytogenetic abnormalities independent of ploidy status had a noticeably longer overall survival (OS) (median 21 months) compared to 8 patients with ≥3 abnormalities (median OS 5 months). These 4 patients also lacked -5/5q or -7 abnormalities. Clonal evolution was present in 3 cases, the same cases with myeloid sarcoma. Complete remission (CR) was achieved in 8/12 (67%) patients with the remaining 4 having refractory disease. Median OS was 8 months.
Conclusions: Our study suggests NT/T-AML occurs predominately in older men. The majority of cases demonstrated large blasts with frequent cytoplasmic blebbing or vacuoles. Myelodysplasia with dyserythropoiesis was common prior to or at AML diagnosis. When viewed independently of NT/T status, complex karyotype (≥3 cytogenetic abnormalities) conferred a decreased OS. However, NT/T-AML in this age group had dramatically better CR and median OS than would be predicted based on complex karyotype alone.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 242, Monday Morning