Grey Zone Lymphomas: Lymphomas with Intermediate Features
Table 2
Common and distinguishing features of BL, DLBCL, and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL (BCLu-DLBCL/BL).
BL
DLBCL
BCLu-DLBCL/BL
Common features
Age
Young children and less frequent young adults
Less frequent in children but frequent in adults of all age groups
Mainly diagnosed in adults
Gender
Male predominance
No real predominance
Localization
Often extranodal (jaw and iliac region)
Nodal and extranodal
Often extranodal (no predominant region) often widespread disease leukemic presentation is possible
Morphology
Frequent mitotic figures and apoptosis often with starry sky pattern
Frequent mitotic figures and apoptosis may be present
Frequent mitotic figures and apoptosis often with starry sky pattern resembling BL
Immunophenotype
CD10, BCL-6 positive, BCL-2 negative
“BL immunophenotype” (CD10, BCL-6 positive, BCL-2 negative) may be present
Variable depending on morphologic features (see text)
Genetic and molecular features
Typical IG-MYC fusion, simple karyotype
Typical IG-MYC fusion may be present
Often non-IG-MYC fusion complex karyotype
Distinguishing features
Morphology
Medium-sized blastic cells with basophilic cytoplasm, no inflammatory background, sometimes cohesive growth pattern Small nucleoli at the periphery, mitotic rate always very high (Ki67 )
Pleomorphic large blastic tumor cells, often inflammatory infiltrate, mitotic rate variable
Genetical and molecular features
Typical cMYC fusion with IG light or heavy chain locus, simple karyotype More complex karyotypes possible (sign of progression)
Other types of cMYC fusions can be present (other than IG as a partner), complex karyotype possible
Combination of BCL2 and/or BCL6 breaks possible (so-called “double or triple hit lymphomas”)
