ALK‐positive large B‐cell lymphoma with strong CD30 expression; a diagnostic pitfall and resistance to brentuximab and crizotinib

Cytomorphological clues for a correct diagnosis of anaplastic lymphoma kinase‐positive large B‐cell lymphoma

“…The cytological features of this entity have not been extensively described with only few case reports in literature. We have tabulated the case reports defining cytological features of ALK + LBCL in Table . Cytologically, the cells are highly atypical, monomorphic and have an immunoblast‐like morphology with abundant cytoplasm, large pleomorphic nuclei and prominent macronucleoli.…”

Diffuse large B-cell lymphoma variants: an update

“…15 CD30 is usually negative, with rare exceptions. 17 c-MYC can be positive by immunohistochemistry, but these tumours do not harbour MYC rearrangement. 15 Cytogenetics and molecular ALK chimaeric proteins resulting from translocations are the main driver of lymphomagenesis.…”

ALK+ large B cell lymphoma presenting as multiple bowel‐obstructing, cytokeratin‐positive tumours

“…Most ALK+ LBCL are CD30‐negative/weak, whereas ALK+ ALCL are strongly and uniformly CD30 positive, making the differential diagnosis theoretically very simple. Nevertheless, as seen in the present case, strong uniform CD30 expression is possible in ALK+ LBCL 6 . Together with an absence of significant expression of common B cell markers (CD20, PAX‐5, CD79a) and strong expression of CD4 and cytotoxic molecules, this may lead to a misdiagnosis of ALK+ ALCL, especially in the presence of an NPM–ALK rearrangement (more characteristic of ALK+ ALCL).…”