Table 2B. ALK-positive anaplastic large... | American Society of Hematology

Table 2B.

ALK-positive anaplastic large cell lymphoma: morphological variants.

	Common variant	Small cell variant	Lymphohistiocytic variant	Nature	Immuno- phenotype
* ALK expression in the small cells is mostly restricted to the nucleus
Other morphological variants seen infrequently include : a neutrophilic-rich variant, a giant cell variant, a sarcomatoid variant.
Hallmark cells	Numerous	Scattered, perivascular, smaller than in the common variant		Neoplastic	CD30⁺   EMA⁺   ALK⁺
Small cells	Absent	Numerous	Variable	Neoplastic	CD30^–/+   EMA^–/+   ALK⁺*
Histiocytes	Variable	Variable	Prominent	Reactive	CD68⁺

	Common variant	Small cell variant	Lymphohistiocytic variant	Nature	Immuno- phenotype
* ALK expression in the small cells is mostly restricted to the nucleus
Other morphological variants seen infrequently include : a neutrophilic-rich variant, a giant cell variant, a sarcomatoid variant.
Hallmark cells	Numerous	Scattered, perivascular, smaller than in the common variant		Neoplastic	CD30⁺   EMA⁺   ALK⁺
Small cells	Absent	Numerous	Variable	Neoplastic	CD30^–/+   EMA^–/+   ALK⁺*
Histiocytes	Variable	Variable	Prominent	Reactive	CD68⁺