Adult T cell lymphoma / leukaemia, ATLL

Definition

A peripheral T-cell neoplasm caused by the human T-cell leukaemia retrovirus, type 1. (HTLV-1).

Synonyms

Epidemiology

 ATLL is endemic in Japan, the Caribbean and Central Africa. Sporadic cases of ATLL occur elsewhere. The median of onset of ATLL is 55 years.

Clinical features

 Patients present with generalised lymphadenopathy. The skin is most commonly involved, followed by lung, liver, gastrointestinal tract and CNS.

Clinical variants:

• acute leukaemia ATLL manifests as a markedly raised WBC with eosinophilia, skin rash, generalised lymphadenopathy, hepatosplenomegaly and hypercalcaemia, with or without lytic bone lesions. Opportunistic infections with Pneumocystis carinii and Strongyloides are common.

• lymphomatous ATLL is characterised by generalised lymphadenopathy without leukaemia.

• chronic ATLL is associated with an exfoliating skin rash and limited numbers of atypical circulating white cells

• smoldering ATLL shows a normal WBC with <5% circulating neoplastic cells, cutaneous and pulmonary lesions. There is usually a long latent period before progression to an acute form.

Histopathology

•  The acute and lymphomatous variants show pleomorphic medium to large pleomorphic lymphoid cells with coursely clumped chromatin and distinct nucleoli. Nodal involvement is diffuse with effacement of the architecture. Lymph nodes may show sinuses dilated with neoplastic cells; there may be an eosinophilia. Marrow infiltration is patchy. The skin shows dermal infiltration with Pautrier-like microabscesses. Variants:

  • anaplastic large cell type: there are large/giant cells with lobulated ("flower cells") or round nuclei, fine chromatin and one or two nucleoli. The cells are CD30-positive1.

• The chronic and smoldering variants have smaller neoplastic cells with minimal pleomorphism. The skin shows a sparse dermal infiltrate with hyperkeratosis. In some cases, the lymph nodes closely mimic Hodgkin lymphoma with paracortical infiltration by small lymphocytes and Reed-Sternberg-like cells. The RS-like cells are EBV-positive and express CD15 and CD30. These cases usually show rapid progression.

• Angioimmunoblastic T-cell lymphoma (AILT)-like.

Immunohistochemistry

†: fresh frozen tissue only

Prognosis

This is an aggressive type of lymphoma with a poor prognosis.

References

0 World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.

1 Karube K, Suzumiya J, Okamoto M, et al. Adult T-cell lymphoma/leukemia with angioimmunoblastic T-cell lymphomalike features: Report of 11 cases. Am J Surg Pathol 2007; 31:216-23

This page last revised 17.2.2007.

©SMUHT/PW Bishop