Streptococcal toxic-shock syndrome due to Streptococcus dysgalactiaesubspecies equisimilis in breast cancer-related lymphedema: a case report

Abstract

BackgroundBreast cancer-related lymphedema often causes cellulitis and is one of the most common complications after breast cancer surgery. Streptococci are the major pathogens underlying such cellulitis. Among the streptococci, the importance of the Lancefield groups C and G is underappreciated; most cases involve Streptococcus dysgalactiaesubspeciesequisimilis. Despite having a relatively weak toxicity compared with group A streptococci, Streptococcus dysgalactiaesubspeciesequisimilis is associated with a mortality rate that is as high as that of group A streptococci in cases of invasive infection because Streptococcus dysgalactiaesubspeciesequisimilis mainly affects elderly individuals who already have various comorbidities.Case presentationAn 83-year-old Japanese woman with breast cancer-related lymphedema in her left upper limb was referred to our hospital with high fever and acute pain with erythema in her left arm. She showed septic shock with disseminated intravascular coagulation. Blood culture showed positive results for Streptococcus dysgalactiaesubspeciesequisimilis, confirming a diagnosis of streptococcal toxic-shock syndrome. She survived after successful intensive care.ConclusionsTo the best of our knowledge, this case represents the first report of Streptococcus dysgalactiaesubspeciesequisimilis-induced streptococcal toxic-shock syndrome in a patient with breast cancer-related lymphedema. Breast cancer-related lymphedema is a common problem, and we must pay attention to invasive streptococcal soft tissue infections, particularly in elderly patients with chronic disease.