Disseminated myofibroblastic papulosis in young individuals - a newly identified entity: a clinicopathological study from a case series of eight patients.

Abstract

Superficial dermal fibroblastic/myofibroblastic proliferation comprises a spectrum of tumours, most of which present as solitary lesions. Generalized forms are exceptionally rare. To describe and analyse a novel entity clinically manifested as disseminated firm papules and histologically characterized by fibroblastic/myofibroblastic proliferation. We conducted a retrospective analysis of eight patients diagnosed between 2010 and 2024, collected from four medical centres. Histopathological review of haematoxylin and eosin-stained sections was performed, alongside available immunohistochemical studies. Whole-exome sequencing was carried out on genomic DNA from three patients, to explore potential genetic causes. The cohort consisted of five female and three male individuals (median age 18 years; range 14-26) presenting with multiple skin-coloured to dark-red papules predominantly on the extremities, buttocks and chest. Histopathology revealed fascicular proliferations of bland spindle cells in the superficial dermis. Immunohistochemically, the lesions were weakly positive for smooth muscle actin and negative for CD68, CD34, desmin and S100 protein, with loss of elastic fibres. No relevant germline driver mutations were detected in peripheral blood DNA. Spontaneous regression occurred in five patients during follow-up. We propose the term 'disseminated myofibroblastic papulosis' for this newly recognized, probably underdiagnosed entity. Given its benign behaviour and frequent self-resolution, a watchful waiting approach after diagnosis is recommended.