Primary Hematopoietic and Lymphoid Tissue ›› Thymus ›› Abnormal

T-cell Lymphoblastic Leukemia/Lymphoma (T-ALL)*

Click Here for Full Size

Microscopic Features:
  • 3-4x larger than a mature RBC
  • High nuclear to cytoplasmic ratio
  • Round Nucleus with immature chromatin (not clumped)
  • Prominent nucleoli
  • Cytoplasm is scant, light blue in colorĀ and lacks granules
Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
  • PB: None
  • BM: None
  • LN: None
May Resemble: Differential Diagnoses:

If in blood, bone marrow or tissue:
T-Lymphoblastic leukemia/lymphoma (T-ALL)
B-Lymphoblastic leukemia/lymphoma (B-ALL)

Classic Immunophenotype:
  • CD3+ (cytoplasmic)
  • CD7+
  • TdT+
  • CD1a (variable)
  • CD2 (variable)
  • CD5 (variable)
  • CD4 (variable)
  • CD8 (variable)
Cartoon Image:

Click and drag
for direct comparison

  • Can arise from thymus (Anterior Mediastinum). Remember the mnemonic for Anterior Mediastinal lesions/masses: 4 Ts (Thymoma, Terrible Lymphoma such as T-lymphoblastic lymphoma, Thyroid neoplasms, and Teratoma or other germ cell neoplasms)

Content Editors/Website Administrators:
Hooman H. Rashidi, MD; John C. Nguyen, MD