Adult T cell Lymphoma leukaemia


Patients with ATLL are most often systemically unwell, with lymph node, hepatic and splenic enlargement, and skin lesions and hypercalcaemia.. Acute forms are most frequent (more that half of cases), but chronic and smouldering presentations also occur. Around two thirds of patients will have circulating abnormal cells.



  • Circulating abnormal lymphocytes are generally present, but may be infrequent
  • Variability of appearance is typical, but generally cells are of medium size with condensed chromatin, cytoplasm is basophilic and relatively abundant.
  • Larger cells may show nucleoli and have a “blast like” appearance
  • Marked nuclear lobation may be seen in some cells and can resemble Sezary cells
  • The classical nuclear appearance resembles a “clover leaf” or “flower” with widely spread individual lobes, but these forms may be infrequent

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Adult T cell leukaemia lymphoma (ATLL)

The film shows fairly typical appearances of ATLL. The variability of cell appearances is shown quite well; overall the most recognisable feature is marked lobation of nuclei (one cell showing separate lobes - the "clover leaf" pattern). Note also the marked cytoplasmic basophilia of the cells. All the cells shown are of medium to large size and the largest cell has an almost "blast like" appearance. The background is difficult to assess on this small field, but platelet count appears low.


The immunophenotype of ATLL is not fully distinctive, but most frequently presents as CD4-expressing T cells with variable and low expression of CD7 and CD3, but bright expression of CD25.



Where the abnormal cells do not circulate, or in difficult cases, the abnormal cells are better detected by biopsy of involved tissues.


Often abnormal with complex change; recurrent abnormalities are described but not unique to ATLL

Genetic testing

Mutations or deletions of tumour suppressor genes CDKN2A (p16), CDK2B (p15), and TP53 (p53) are reported in approximately 50% of ATLL patients.


The disease arises in association with previous exposure to the virus HTLV1 (endemic areas include Japan, the Caribbean, West Africa, and Brazil). Serology for HTLV1 is generally positive, but in difficult cases it may be necessary to look for HTLV1 viral DNA in tumour cells.