5th June 2025

A 55-year-old man presents with several red-purple nodules on his chest, that have developed slowly over the past year.

A 55-year-old man presents with several red-purple nodules on his chest, that have developed slowly over the past year. Lymph node examination is normal as is the rest of the clinical examination. He is originally from North America and works outdoors as a gardener. A biopsy is taken and histology shows diffuse infiltration of the dermis with marginal zone B-cells. Which organism is most commonly associated with this condition?

Select the SINGLE most appropriate option from the list below. Select ONE option only.