SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.
ALCL is a T-cell lymphoma consisting of lymphoid cells that are usually large with abundant cytoplasm and pleomorphic, often horseshoe-shaped nuclei. Most cases express cytotoxic granule-associated proteins.
The majority are positive for the anaplastic lymphoma kinase (ALK) protein.
Grade is T-cell (5) unless pathologist specifically designates as a B-cell (see G2 rule).
Note: This neoplasm has a small cell variant. (See below.)
Anaplastic large cell lymphoma, ALK-positive (ALCL, ALK+) frequently involves both lymph nodes and extranodal sites.The most commonly involved extranodal sites include skin, bone, soft tissue, lung, and liver. Involvement of the GI system and CNS is rare. Mediastinal disease is less frequent than in Classical Hodgkin lymphoma
Bone marrow involvement occurs in approximately 10-30% depending on the tests performed. The small cell variant may have a leukemic presentation with peripheral blood involvement.
Patients often have B-symptoms, especially high fever.
The immunophenotyping is vital in differentiating this neoplasm from large B-cell lymphoma with immunoblastic/plasmablastic features expressing ALK protein, rhabdomyosarcoma, and inflammatory myofibroblastic tumors.
Definitive Diagnostic Methods
Bone marrow biopsy
T-cell receptor (TCR) genes are clonally rearranged
t (2;5) (p23;q35)
Positive/Negative: EMA, granzyme B, perforin, TIA-1