Review Question - QID 101351

This patient's clinical presentation is consistent with T-cell acute lymphoblastic leukemia (ALL). Pre-T-cells express the CD2 surface marker.

ALL is a neoplastic proliferation of leukocytes in the bone marrow. Two subtypes exist: B-cell (B-ALL, more common) and T-cell (T-ALL, less common). Both diseases typically present with recurrent infections, bleeding, fatigue, hepatosplenomegaly, and lymphadenopathy. Unlike B-ALL, T-ALL classically presents with a mediastinal mass. A mediastinal mass might be suspected as responsible for this patient's shortness of breath (compression of the trachea) and transient facial edema (superior vena cava syndrome). Recall that pre-B-cells express surface markers CD10, CD19, and CD20 while pre-T-cells express surface markers CD2, CD3, CD4, CD5, CD7, and CD8.

Attarbaschi et al. found that mediastinal masses in T-ALL have no prognostic relevance though patients with T-ALL frequently present with unfavorable features at diagnosis. These patients are considered to have a higher risk to relapse. Recently, the outcomes of this ALL subtype has been improved by intensified chemotherapy, which was previously a very poor prognosis.

Young et al. review the detection of childhood cancers including leukemias and lymphomas. Leukemia may present early on with nonspecific symptoms similar to those of a viral infection but should be suspected if these symptoms persist or are seen in association with abnormal bleeding, bone pain, lymphadenopathy or hepatosplenomegaly. Lymphoma may present as a painless mass (most commonly in the neck) as well as generalized symptoms including fever and weight loss.

Illustration A depicts a bone marrow aspirate from a child with T-ALL. Illustration B depicts a peripheral blood smear of a child with ALL.

Incorrect Answers:
Answers 2-4: These are pre-B-cell surface markers. The patient's presentation is more consistent with T-ALL.

Answer 5: CD16 is a natural killer (NK) cell surface marker.