Skin‐associated lymphoid tissue could be a sign of systemic disease

Abstract

DEAR EDITOR, Kamido et al. reported a 63-year-old woman with Schnitzler syndrome but recurrent erythematous patches even with anakinra treatment. 1 Skin biopsy obtained before anakinra initiation showed an underlying lymphoid follicle with a germinal centre surrounded by plasma cells. Moreover, vascularity with high endothelial venule formation was also seen. The authors concluded it was an inducible skin-associated lymphoid tissue, probably triggered by chronic inflammation.However, given these dermatopathological features are rarely reported in patients with Schnitzler syndrome, as well as the inadequate clinical response to anakinra, an alternative diagnosis should be considered. Of note, these findings are reminiscent of Castleman disease. Germinal centres with surrounding plasma cells and hypervascularity are not only seen in lymph nodes of patients with idiopathic multicentric Castleman disease but could also involve their bone marrow as well as skin. 2 The erythematous skin plaques are usually neither painful nor pruritic, and involve face and trunk. It could precede the development of other systemic features of idiopathic multicentric Castleman disease. 3 Histologically, it may also be reported as 'cutaneous plasmacytosis', which is thought to share a similar pathogenesis with Castleman disease in terms of hypercytokinaemia, in particular interleukin (IL)-6. 4 Although corticosteroid treatment could provide symptomatic relief, its tapering always leads to recurrence of the skin lesions, which happened in the patient reported by Kamido et al., while a recent study suggested the effectiveness of tocilizumab by targeting IL-6. 3