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Case 104 - Discussion

Hematopathology Case

  • IHC: CD20+. CD79a+, CD5+, BCL2+, Cyclin D1+, BCL6-, CD10-.

  • Cytogenetics: Positive for t(11;14)(q13;q32) and t(8;14) involving c-Myc gene.

  • Diagnosis: blastoid mantle cell lymphoma.

  • The patient was found to lymphoma infiltration in peripheral blood, spinal fluid, skin, and cervical lymph node later. He died 2 weeks later.

  • Personal note: The tumor cells in this cases show blastoid morphology with "monotonous medium sized cells, round or irregular nuclei, and fine chromatin". The major differential diagnosis based on the morphology should include Burkitt lymphoma, blastoid mantle cell lymphoma, and lymphoblastic lymphoma.

Mantle Cell Lymphoma
 

The Key Features

  • Architecture: monomorphic lymphoid proliferation with a vaguely nodular, diffuse or mantle zone growth pattern;

  • Cytology: small to medium size, slightly irregular nuclear contours, resembling centrocytes; No neoplastic transformed cells resembling centroblasts, immunoblasts, or paraimmunoblasts;

  • Hyalinized small vessels commonly present;

  • CD5+, BCL1+, CD43+, CD10-/+, BCL6-;

  • t(11;14)(q13;q32), IGH@/BCL1 fusion gene.

 

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 histiocytes 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+, Cyclin D1-.

  • Marginal zone lymphoma: more clear cytoplasm, more irregular nuclear contour, Cyclin D1-.

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;

  • SOX11: very sensitive and specific, even positive in BCL1- cases;

  • CD10-/+, BCL6-, CD23-/+.

CYTOGENETIC STUDIES

  • t(11;14)(q13;q32), 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.
  • Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. World Health Organization classification of tumours. Lyon (France): IARC Press; 2001.