Case 107 - Discussion

Uploaded: 2009-11-17, Updated: 2009-11-17

By flow cytometry assay, the monoclonal B-cell are positive for CD20 bright, CD79a, CD5, and negative for CD23.

Diagnosis: blastoid mantle cell lymphoma involving peripheral blood and CSF.

CASE STUDY

CLINICAL FEATURES

• MCL comprise approximately 3-10% of NHL;
• Age: middle to older age, median age 60 years; M:F=2:1;

• Location: mostly lymph nodes, also spleen and bone marrow; most common extranodal sites, GI tract and Waldeyer's ring;

• Most cases of multiple lymphomatous polyposis of GI tract represent MCL;

• Clinical features: most patients present with stage III or IV with lymphadenopathy,  hepatosplenomegaly; >50% of cases with massive splenomegaly and marrow involvement; >25% cases with peripheral blood involvement that can mimic prolymphocytic leukemia;

• No transformation into large cell lymphoma, but can increase nuclear size, pleomorphism, chromatin dispersal and mitotic activity.

MICROSCOPIC FINDINGS

• Architecture: effacement of lymph node by a monomorphic lymphoid proliferation with a vaguely nodular, diffuse or mantle zone growth pattern, or rarely a true follicular growth pattern;

• Cytology: small to medium size, slightly larger than the normal lymphocytes; slightly irregular nuclear contours, resembling centrocytes but often have slightly less irregular nuclear contours; occasional round nuclei, resembling B-CLL/SLL;  the nuclei have moderately dispersed chromatin with inconspicuous nucleoli;

• No neoplastic transformed cells resembling centroblasts, immunoblasts, or paraimmunoblasts; no pseudofollicles;

• Hyalinized small vessels commonly present;

• Many cases have scattered single epithelioid histocytes with a "starry sky" appearance;

SUBTYPES/VARIANTS

• Blastoid variants: younger age, medium 40 years,

  • Classic type: cells resemble lymphoblasts with dispersed chromatin and a high mitotic rate (>10/10HPF, often >20-30/10HPF);

  • Pleomorphic type: heterogeneous cells with large cleaved to oval nuclei and pale cytoplasm and possible prominent nucleoli.

• Small round lymphocytes: more clumped chromatin, either admixed or predominant, mimicking small cell lymphoma;

• Prominent foci of cells with abundant pale cytoplasm resembling marginal zone cell lymphoma.

DIFFERENTIAL DIAGNOSES

• SLL/CLL: more regular nuclear contour, proliferative center, CD23+, BCL1-.

• Marginal zone lymphoma: monocytoid, clear cytoplasm, BCL1-.

IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS

• Positive for B-cell markers: CD 19, CD 20, CD 22, CD79a;

• Positive for sIgM and sIgD;

• CD5+, BCL2+, FMC7+, CD43+;

• BCL1 (Cyclin D1) positive in all cases, even in CD5- cases;

• CD10-, BCL6-, CD23-.

CYTOGENETIC STUDIES

• t(11;14)(q13;q32), 70-75% cases, IgH-BCL1 fusion gene resulting in over-expression Cyclin D1.

TREATMENT AND PROGNOSIS

• Not indolent, but moderately aggressive. Median survival, 3-5 years.

REFERENCES

• Practical Diagnosis of Hematologic Disorders, Fourth Edition. By Carl R. Kjeldsberg, 2006.

• Swerdlow, S.H., Campo, E., Harris, N.L., Jaffe, E.S., Pileri, S.A., Stein, H., Thiele, J., Vardiman, J.W. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, Fourth Edition. 2008.