Anaplastic large cell lymphoma, ALK+

Clinical

 • First 3 decades of life, M>F

 • Often nodal + extranodal sites (MC are skin, bone, soft tissue, lungs, liver)

 • BM involvement often subtle

 • Small cell variant can have leukemic presentation

 • Some isolated skin - may be indolent

 • Most present w advanced stage + B symptoms

Histology

 • Variable number of cells w horseshoe- or kidney-shaped nuclei, sometimes w eosinophilic hof (Hallmark cells)

 • Donut cells (nuclear pseudoinclusions)

 • Multinucleated cells, wreath-like

 • Nucleoli can be seen but are usually not eosinophilic/inclusion-like

 • May grow in LN sinuses and resemble metastatic tumor

 • Lymphohistiocytic pattern: mixed w reactive histiocytes, neoplastic cells often around vessels

 • Small cell pattern: small to medium w irregular nuclei, sometimes fried-egg morphology, but still has hallmark cells around vessels

 • Hodgkin-like pattern: mimics NS CHL

 • Composite pattern: more than one

 • Rare cases are hypocellular/spindled



Dr. Laura Brown @lauraebrown



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