18. Diffuse large B-cell lymphoma (DLBCL)

Staining: HE and PAS

Overview

Organ: Lymph node (not recognizable)

Description:

The tumor cells form no structures. HE on the left and PAS on the right.

No healthy lymph node tissue is visible. The tumor cells form no structures (like glands or nests). The cells are large and show severe atypia/pleiomorphism, almost anaplastic. The cells resemble centroblasts and are therefore said to be centroblastic in appearance or centroblastoid. There is high mitotic activity (many mitotic figures).

On PAS staining are PAS-positive inclusion bodies in the cytoplasm and nuclei visible, so called Russell bodies and Dutcher bodies, respectively. These inclusion bodies are comprised of immunoglobulin.

Diagnosis: Diffuse large B-cell lymphoma.

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Causes:

• Primary type: mutations in
  • Myc
  • BCL2
  • BCL6
• Secondary type: Richter transformation from CLL, MZL or FL

Theory:

Necrosis is also a common histological finding in DLBCL but it can’t be seen here.