[471] Angioimmunoblastic T-Cell Lymphoma: Dermatopathological Features in a Series of 40 Cases.

Jose Cardoso, Emma Benton, Kikkeri Naresh, Ayoma Attygalle, Manuel Rodriguez, Miguel A Piris, Socorro M Rodriguez-Pinilla, Werner Kempf, Alistair Robson. St. John's Institute of Dermatology, London, United Kingdom; Imperial College Hospital, London, United Kingdom; Royal Marsden Hospital, London, United Kingdom; University College Hospital, London, United Kingdom; Spanish National Cancer Institute, Madrid, Spain; University Hospital Zurich, Switzerland

Background: Angioimmunoblastic T-cell lymphoma (AIL) is a systemic peripheral T-cell lymphoma with frequent skin involvement. Cutaneous manifestations are quite variable and frequently non-specific, the most common being a rash mimicking a drug eruption or a viral illness. Papulonodular, urticarial and purpuric lesions are also described. The dermatopathological features are correspondingly variable and in many reported cases they received little attention.
Design: Forty cases of cutaneous involvement by AIL were assessed dermatopathologically, with regard to the morphological and immunophenotypical features.
Results: Sixteen cases had a granulomatous pattern, varying from small granulomas to marked involvement suggestive of infection. Seventeen had a relatively non-specific superficial and deep perivascular infiltrate. In 16 cases there was often striking, usually localised, permeation of the eccrine glands, although syringotropism proper was uncommon. In only 7 cases were there prominent or easily identifiable eosinophils. In 18 cases cytological atypia was mild or minimal.
In most infiltrates the neoplastic cells had a peripheral CD4-positive T-cell phenotype. In 20/21 cases and 14/16 cases there were immunopositive cells for PD-1 and CXCL13, respectively, but these were almost always a minority, often just a few cells being positive. Similarly, CD10 was positive in 14/25 cases but in a substantial number of cells in only 2 cases. Epstein-Barr RNA (EBER) was positive in 12 of 30 cases tested, again usually in only a few cells. Four cases had a clearly malignant B-cell population. In at least 3 cases the cutaneous proliferation was of different lineage to the nodal neoplastic cells.
Conclusions: In cutaneous involvement by AIL, the diagnosis of lymphoma may be missed due to little atypia, the "non-specific" pattern of the infiltrate and/or conspicuous granulomas. Furthermore, in cases of evident lymphoma, the frequent absence of the typical AIL signature viz. eosinophil-rich CD10-positive EBER-positive infiltrate can lead to the correct diagnosis being overlooked.
Category: Dermatopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 109, Wednesday Afternoon

 

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