Different Predilection of the Anatomic Distribution of Extra-Lymphoid Involvement in T-Lymphoblastic Lymphoma and B-Lymphoblastic Lymphoma of Childhood
Micah Will, Liqun Yin, Xiayuan Liang. University of Colorado Denver School of Medicine, Aurora, CO
Background: Lymphoblastic lymphoma (LBL) is relatively uncommon compared to lymphoblastic leukemia. LBL may exist with or without a leukemic phase and in some cases may present with extra-lymphoid involvement. Extra-lymphoid presentation may cause a diagnostic challenge if it is not suspected as the differential diagnosis for small round blue cell tumors in children is broad. The characteristic distribution of extra-lymphoid involvement of LBL has not been fully elucidated. We examined a series of pediatric patients with LBL between 1991 and 2011 at our institution.
Design: 43 cases of LBL (23 B-LBL and 20 T-LBL) at Children's Hospital CO were evaluated. All patients were < 20 years of age. Extra-lymphoid involvement is defined as the presence of a tumor mass or tumor cells outside lymph nodes, thymus, spleen, or tonsils. Bone marrow (BM) and cerebrospinal fluid (CSF) involvement was counted separately from extra-lymphoid involvement. The differences of age, sex, and anatomic distribution of extra-lymphoid tumors are compared between B-LBL and T-LBL.
Results: 1) B-LBL tended to occur in the head, bone, and BM more frequent than T-LBL. 2) T-LBL tended to involve body cavities (pleural/pericardial effusion and CSF) and GU system more often than B-LBL. Due to small sample size, only the difference in pleural/pericardial effusion and BM involvement reached statistical significance (p = 0.0183 and p = 0.0281).
|# of cases||23||20|
|Mean age (y)||9.3||11.3||0.2288*|
|Extra-lymphoid involvement||14/22 (63.6%)||9/20 (45.0%)||0.1001♠|
|Head||5/14 (35.7%)||1/9 (11.1%)||0.2082♠|
|Bone||5/14 (36.7.8%)||0/9 (0%)||0.0595♠|
|Soft tissue||3/14 (21.4%)||1/9 (11.1%)||0.4830♠|
|Breast||1/14 (7.1%)||1/9 (11.1%)||0.6403♠|
|GU||1/14 (7.1%)||3/9 (33.3%)||0.1470♠|
|GI||1/14 (7.1%)||0/9 (0%)||0.6087♠|
|Skin||2/14 (14.3%)||1/9 (11.1%)||0.6680♠|
|Pleural/pericardial effusion||1/14 (7.1%)||5/9 (55.6%)||0.0183♠|
|BM+||13/20 (65.0%)||6/20 (30.0%)||0.0281♠|
|CSF+||2/21 (9.5%)||4/20 (20%)||0.3073♠|