Immunohistochemistry with hematoxylin counterstain.
(A) The lymphoma cells are strongly positive for ALK with a cytoplasmic pattern of staining.
(B) All of the neoplastic cells are strongly positive for CD30 in a membranous and paranuclear, dot-like pattern (target-like).
(C) The neoplastic cells are negative for CD3. Small reactive T cells are positive and serve as an internal control.
(D) The neoplastic cells are positive for EMA (MUC1).
Reproduced with permission from: Ioachim HL, Medeiros LJ. Ioachim’s Lymph Node Pathology, 4th ed, Lippincott Williams & Wilkins, Philadelphia 2009. Copyright © 2009 Lippincott Williams & Wilkins.
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