A lymph node biopsy shows large pleomorphic cells in a sinusoidal distribution (see image). Which of the following would support a diagnosis of anaplastic large cell lymphoma (ALCL)?
Variable positivity with CD30
Positivity for Epstein-Barr virus
Positivity for cytotoxic granule-associated proteins such as TIA-1
Dim nuclear PAX5 positivity
Answer : C Positivity for cytotoxic granule-associated proteins such as TIA-1
Diffuse and strong CD30 positivity is required for diagnosing anaplastic large cell lymphoma (ALCL). Other lymphomas, both B-cell and T-cell, may express some CD30.
Epstein-Barr virus is not associated with ALCL.
ALCL frequently expresses cytotoxic granule-associated proteins such as TIA-a.
ALCL is a T-cell lymphoma. Expression of B-cell markers such as PAX-5 in malignant cells supports the diagnosis of a B-cell lymphoma.