Visseaux LV, et al. - This trial entailed the characterization of distinctive eruption referred to as “insect bite-like reaction”, or “eosinophilic dermatosis of hematologic malignancy. In addition, authors explored its pathogenesis and association with the underlying hematological B-cell malignancies (BCM). The denomination “T-cell papulosis associated with B-cell malignancy” (TCP-BCM) was proposed for this distinctive eruption. Clinicians could easily detect this condition despite its various histopathological pictures. Informed pathologists could detect it via certain pivotal features. The clinicopathological aspect and the prolonged regressive and recurrent course of the disease could be elucidated through an extravasation of tumor B-cells with skin-homing properties associated with a secondary, predominant, T-cell immune reaction.

Methods

• The plot of this research was a multicenter retrospective study.
• Experts analyzed 37 patients with a BCM and a cutaneous eruption in the form of chronic and/or recurrent papules, papulo-vesicles and/or nodules, who were participants of the French Study Group on Cutaneous Lymphomas.
• This study comprised of an appraisal of the clinical, histopathological, immunohistochemical and molecular data.

Results

• Findings did not record any notable insect bite history or seasonal predominance.
• The subjects presented with pruritic papules (81%), papulo-vesicles (43%) and nodules (38%), predominated frequently in the head and neck region (84%), without complete remission periods in maximum cases (57%).
• Data demonstrated that the predominant associated BCM was chronic lymphocytic leukemia (73%).
• The following results were yielded via histological and immunohistochemical review:
• A dense dermal lymphocytic infiltrate predominantly composed of T lymphocytes (100%), with frequent eosinophils (77.6%);
• A perivascular and periadnexial (most often pilotropic) pattern (77.6%), sometimes suggestive of a pilotropic mycosis fungoides.
• In 47% of cases, clusters of tumor B-cells were detected with the aid of appropriate phenotyping markers.
• Researchers detected a B-cell clone in skin lesions (identical to the blood clone in 9 cases) in 10/14 cases (71.4%) tested for B-cell IgH gene rearrangement.
• Meanwhile, the presence of T-cell clone was not found.