Invasive Streptococcus agalactiae septic arthritis as an initial presentation of tonsillar carcinoma.

Invasive group B streptococcus (GBS) infection causes substantial morbidity and mortality among adults, but only in the last three decades has the role of GBS as a serious pathogen in the nonpregnant adult been better defined. It has been found that one or more serious underlying medical conditions predisposing to infection can be identified in almost all adults with invasive GBS disease. We report a 64-year-old man who had tonsillar carcinoma presenting with right knee GBS septic arthritis. In view of the rarity of invasive GBS infections in healthy non-pregnant adults, and its association with serious underlying conditions, high case fatality rates, and the need for higher doses of penicillin used in treatment, clinicians need to exercise vigilance when dealing with this disease.