A Practical Approach to the Diagnosis of Common Hematopoietic and Solid Tumors of Childhood
Case 5 -
Anaplastic Large Cell Lymphoma of T/null-cell Phenotype, Systemic Type (ALK-Positive), Monomorphic Variant
D. Ashley Hill, M.D.
Mihaela Onciu M.D.
A15-year-old boy presented with three-week fever, not
responding to antibiotics, and isolated left inguinal lymphadenopathy. An excisional lymph node biopsy
was performed. The excised inguinal lymph node measured 2.5 cm in greatest dimension. No additional
disease was identified at staging work-up.
Within the enlarged lymph node the architecture was
subtotally effaced by a lymphoid tumor with diffuse growth pattern and interfollicular distribution. At
low magnification the tumor had a "starry-sky" appearance imparted by frequent "tingible-body"
macrophages scattered throughout the infiltrate. The relatively monotonous tumor cells were
predominantly large, with irregular nuclear outline and abundant pale amphophilic cytoplasm. Frequent
mitotic figures were noted.
- Burkitt lymphoma
- Diffuse large B-cell lymphoma
- Peripheral T-cell lymphoma, unspecified
- Anaplastic large cell lymphoma, monomorphic variant.
Immunophenotypic Findings (Immunohistochemistry):
The tumor cells were
strongly and diffusely positive for CD45, CD43, CD30, ALK, and EMA, weakly positive for CD3 and CD45RO,
and negative for CD20. The latter stain highlighted the small residual normal follicles, and the
interfollicular (paracortical) growth pattern of this neoplasm.
RT-PCR positive for the NPM-ALK fusion transcript. Conventional cytogenetic analysis: positive for the
Anaplastic large cell lymphoma of T/null-cell phenotype,
systemic type (ALK-positive), monomorphic variant.