Multicentric reticulohistiocytosis post-COVID-19: a case report.

BACKGROUND: Multicentric reticulohistiocytosis (MRH) stands as a rare and challenging systemic granulomatous disease characterized by its predilection for skin and joint involvement, confounding clinicians with its infrequent presentation and systemic manifestations.

CASE DESCRIPTION: This compelling case presentation unravels the intricate complexity of MRH, exemplifying its unique clinical course. Following mild upper respiratory coronavirus disease 2019 (COVID-19) symptoms, the patient manifested purplish-pink papular lesions on both the skin and mucosa, accompanied by debilitating arthralgias. A diagnostic skin biopsy, a pivotal tool in MRH diagnosis, confirmed the presence of this granulomatous disorder, underlining its systemic impact. Strategic therapeutic intervention involving a combination of steroids and methotrexate demonstrated remarkable efficacy, culminating in the resolution of symptoms within 3-month. The absence of malignancy upon thorough screening further amplifies the perplexing nature of MRH.

CONCLUSIONS: This seminal case not only bridges the realms of rare systemic disorders but also marks the first known instance of MRH emerging post-COVID-19. It underscores the imperative consideration of MRH in analogous scenarios and provides invaluable insights into the nuanced interplay of MRH symptoms, diagnosis, and therapeutic strategies following viral triggers. This comprehensive exploration enriches our scientific understanding, offering nuanced perspectives on the manifestations and intricate dynamics of MRH in the context of post-viral sequelae.