Mediastinal gray zone lymphomas share features of both a mediastinal large B-cell lymphoma and classic Hodgkin's disease.
Synonym: grey zone lymphoma, large B-cell lymphoma with Hodgkin features, Hodgkin-like anaplastic large cell lymphoma
Features:
(1) large anterior mediastinal mass
(2) variable lymphadenopathy of supraclavicular lymph nodes
(3) large pleomorphic B-cells in a fibrous stroma
(4) areas of tumor necrosis common
(5) histology that overlaps between large B-cell lymphoma and Hodgkin's disease
(6) immunophenotype overlaps between large B-cell lymphoma and Hodgkin's disease
Immunohistochemistry:
(1) CD45 frequently positive
(2) CD15 variable
(3) CD30 variable
(4) CD20 usually positive
(5) variable bcl6
(6) ALK negative
(7) often show PAX5, OCT2 and BOB.1
The diagnosis should be suspect with pleomorphic lymphoma that may show:
(1) Hodgkin-like features but usual markers negative and B-cell markers positive
(2) diffuse large B-cell lymphoma features with CD15 and/or CD30 positivity and/or Reed-Sternberg cells
