Initial unsolicited report received from the literature on 23 May 2018. This case is linked to 2018SA144034, 2018SA144049, 2018SA144061, 2018SA144069, 2018SA144075, 2018SA144105, 2018SA144628, 2018SA144597, 2018SA144797, 2018SA144618, 2018SA144640, 2018SA145180, 2018SA145155, 2018SA141516, 2018SA144697 (same literature). The following is verbatim from the article: Sterile abscess formation may rarely complicate immunization with vaccines containing aluminum adjuvants. Such reactions may exhibit a delayed response following immunization of several weeks, and may occur only after multiple doses of the vaccine have been previously received without incident. An awareness of this phenomenon may be helpful for those health care providers involved with the immunization of children. Sterile abscess formation following immunization with aluminum-containing vaccines, followed by the first systematic review of both the literature and the Vaccine Adverse event reporting system (VAERS) database. VAERS ID for this case is 295254-1. This case involves a 17-month-old female patient who was vaccinated with dose of DIPHTHERIA, TETANUS AND NOS PERTUSSIS VACCINE (DTP) (Batch number, expiration date, dose, route was not reported) in left leg (left thigh) on an unspecified date during a pediatric well baby visit. The patient's medical history was not reported. She had no history of constitutional symptoms or trauma. Concomitant medications were not reported. On an unspecified date, 10 days following the vaccination, the patient presented to the emergency department with acute onset of inability to bear weight on her left leg. Physical examination demonstrated a fullness with measured asymmetry to her left thigh. Laboratory and diagnostic findings included CBC results - white blood cell count of 12,300; with 32 neutrophils, 49 lymphocytes, 9 monocytes and 10 eosinophils. She had elevated creatine phosphokinase (CPK) and minimal elevation of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Sedimentation rate was 12, and C-reactive protein was minimally elevated. Radiographs of the left femur demonstrated soft tissue swelling, but no osseous abnormality. MRI demonstrated myositis involving the vastus medialis, vastus intermedius and vastus lateralis muscles with edema and a central serpigenous collection of fluid. Culture of the fluid revealed no growth. Following intravenous gadolinium there was prompt hyperemic enhancement of the muscles, with an area of low signal representing the abscess and surrounding ring enhancement. There was no mass identified and the marrow had normal signal characteristics. Post contrast image showed the long length of the myositis surrounding the shaft of the femur with a central area of nonenhancement representing the sterile abscess, surrounded by the ring enhancement. Patient was diagnosed with sterile abscess. On an unspecified date, the patient was hospitalized. Corrective treatment was not reported. On an unspecified date, the patient recovered from the events. The patient was discharged from the hospital without receiving antibiotics or invasive surgical intervention. With conservative therapy, the pediatrician reported that the patient returned to normal activity within seven days. Documents held by sender: none. Sender's Comments: This case concerns an infant who developed sterile abscess and myositis in her left thigh 10 days after being vaccinated with DTP vaccine at that site. The time to onset is compatible. There is, however, no information regarding patient's medical condition at the time of vaccination. Lab tests point towards a possible allergic etiology but the same has not been established with allergic testing for aluminum. Based upon the reported information, the role of the vaccine cannot be assessed.