COVID-19 vaccine-associated ganulomatous mass mimicking a sarcoma: a case report.

Several studies have previously documented the development of complications stemming from injection with one of the various COVID-19 vaccines. No study, however, has discussed the spontaneous development of a soft tissue mass shortly after a COVID-19 vaccine injection. We report on 66-year-old female with concerns of a growing shoulder mass, 2 weeks after receiving a COVID-19 vaccine booster. Initial work-up with X-ray and MRI was concerning for a soft tissue neoplasm, specifically a soft tissue sarcoma. Subsequent ultrasound guided biopsy demonstrated a benign granulomatous lesion. No further management was required as the lesion spontaneously resolved during a 3-month follow-up period.