T-cell papulosis associated with B-cell malignancy: a distinctive clinicopathologic entity.

BACKGROUND: A distinctive eruption referred to as 'insect bite-like reaction' or 'eosinophilic dermatosis of haematological malignancy' has been described during the course of haematological B-cell malignancies (BCM). However, its clinical evolution, histopathological features and pathogenesis remain unclear. OBJECTIVES: To characterize this eruption and to investigate its pathogenesis and relationship with the underlying BCM. METHODS: In this multicenter retrospective study of the French Study Group on Cutaneous Lymphomas, 37 patients with a BCM and a cutaneous eruption consisting in chronic and/or recurrent papules, papulo-vesicles and/or nodules were included. Clinical, histopathological, immunohistochemical and molecular data were reviewed. RESULTS: No significant insect bite history or seasonal predominance was recorded. Patients had pruritic papules (81%), papulo-vesicles (43%) and nodules (38%), often predominated in the head and neck region (84%), without complete remission periods in most cases (57%). The predominant associated BCM was chronic lymphocytic leukaemia (73%). Histological and immunohistochemical review showed a dense dermal lymphocytic infiltrate predominantly composed of T lymphocytes (100%), with frequent eosinophils (77.6%); a perivascular and periadnexal (most often folliculotropic) pattern (77.6%), sometimes suggestive of a folliculotropic mycosis fungoides; clusters of tumour B cells were identified in 47% of cases using appropriate phenotyping markers. In 10/14 cases (71.4%) tested for B-cell IgH gene rearrangement, a B-cell clone was identified in skin lesions (identical to the blood clone in nine cases), whereas no T-cell clone was present. CONCLUSION: We propose the denomination 'T-cell papulosis associated with B-cell malignancy' (TCP-BCM) for this distinctive eruption. Although resulting in various histopathological pictures, it can be easily recognized by clinicians and may be identified by informed pathologists relying on some key features. An extravasation of tumour B cells with skin-homing properties associated with a secondary, predominant, T-cell immune reaction could explain the clinicopathologic aspect and the prolonged regressive and recurrent course of the disease.

[Eosinophilic dermatosis associated with hematological disorders: A clinical, histopathological and immunohistochemical study of six observations]. / Dermatose éosinophilique associée aux hémopathies : étude clinique, histopathologique et immunohistochimique de six cas.

BACKGROUND: Eosinophilic dermatosis of hematologic disease (EDH) or insect bite-like reaction is a pruritic dermatitis described mostly in patients with chronic lymphocytic leukaemia (CLL). We describe six patients with the disorder in association with CLL and other blood dyscrasias. PATIENTS AND METHODS: We reviewed the medical records of patients with EDH seen between 2004 and 2009 in our department and re-examined histological slides. RESULTS: Mean age at dermatosis onset was 75.6 years and the sex ratio was 1. There were three CLL, two mantle-cell lymphomas and one MALT-type lymphoma. The dermatitis was quite polymorphic, with erythematous papules, wheals and plaques. The initial skin lesions appeared at the same time as or after the diagnosis of haematological neoplasm. Their reappearance heralded relapse of the blood disease in three cases. Histologically, all lesions had a dense dermal infiltrate of small, mostly CD4+ T-cells, with numerous eosinophils. In three patients, there was marked folliculotropism, resembling folliculotropic T-cell lymphoma. In most cases, EDH disappeared after appropriate chemotherapy for the blood disorder. DISCUSSION: Our cases show that the clinical expression of EDH is quite polymorphic. Its appearance may precede relapse of or may indicate prompt search screening for blood dyscrasia. The most efficient treatment of this dermatosis appears to be specific chemotherapy for the blood dyscrasia. There is reason to believe that a population of T-helper 2 (Th2) lymphocytes, reactive to malignant B-cells, induces tissue eosinophilia, mainly through production of interleukin (IL)-5, among other cytokines. Eosinophils appear to be the main effector cells.