Fibrinoid necrosis/bursal tissue necrosis; Extensive inflammation in the bursal space; Bursal foreign body reaction/multiple white, hardened caseous-appearing material in the shoulder/hardened, chalklike flakes that represented reactive changes; Shoulder injury related to vaccine administration; Impingement syndrome; Multiple redirections of the needle while injecting the vaccine; Inadvertent injection of influenza vaccine into the subacromial bursa; This literature case was received on 30-Aug-2021 and concerned 51-year-old, female patient.   Literature on surgical management of shoulder injury related to vaccine administration (SIRVA) was limited. This case, described a patient who presented with significant rotator cuff bursitis and bursal foreign body reaction 12 weeks after influenza vaccine administration, managed with arthroscopic surgical intervention after failed conservative management.  The patient's medical history and concomitant medications were not reported.   On an unknown date, the patient was vaccinated with influenza virus vaccine polyvalent (brand not specified; anatomical location: right deltoid, dose, route of administration and indication: not reported). The batch number was not reported. The patient described the experience as being traumatic because of multiple redirections of the needle while injecting the vaccine (explicitly coded as 'Product administration error'). Also, it was reported that, likely inadvertent injection of influenza vaccine into the subacromial bursa happened (explicitly coded as 'Vaccine administered at inappropriate site' and 'Inappropriate route of vaccination').  On an unknown date, over 48 hours after receiving influenza virus vaccine polyvalent, the patient developed severe shoulder pain and weakness. The pain was most pronounced with attempted shoulder elevation.  On an unknown date, 12 weeks after receiving influenza virus vaccine polyvalent, the patient reported 3 months of severe right shoulder pain, that began after a flu vaccination administered into the right deltoid. The patient was evaluated and diagnosed with rotator cuff bursitis and impingement syndrome.  On an unknown date, oral medication consisting of therapeutic doses of nonsteroidal anti-inflammatory drugs were prescribed but did not result in any appreciable benefit. The patient was subsequently treated with a cortisone subacromial injection and referred to physical therapy for rotator cuff-specific exercises. This resulted in only temporary reduction in patient's symptoms, so a magnetic resonance image (MRI) of the shoulder was ordered. The MRI revealed evidence of severe shoulder bursitis with a large volume of fluid and solid-appearing heterogeneous bodies that extended throughout the subacromial space. There was no evidence of rotator cuff tear. On review of the MRI, the patient was sent to the shoulder subspecialty clinic for evaluation. Her physical examination was unchanged from the initial visit. Specifically, the patient had significant evidence of shoulder bursitis and shoulder pain with minimal motion especially when attempted overhead. The patient had limited range of motion as a result of pain; this was most pronounced with attempted forward flexion and/or abduction. Her active elevation, neutral external rotation, and abduction were 90degree, 25 degree and 70 degree, respectively. Patient's external rotation strength was 4/5 and she was neurovascularly intact. No erythema or warmth was noted. The patient had a positive empty can shoulder test. The patient underwent an arthroscopic shoulder debridement, subacromial bursectomy, and intraoperative cultures of the bursal tissue. At the time of surgery, the patient was noted to have extensive inflammation in the bursal space. In addition, the patient had multiple white, hardened caseous-appearing material in the shoulder. This material was distinct from the bursae. These relatively large bodies were evacuated from the shoulder subacromial space and sent for culture and histologic analysis. Next, the rotator cuff was evaluated and noted to be intact. Her glenohumeral joint was evaluated and found to have a normal appearance without any significant abnormality. The patient noted significant relief in her symptoms after surgery. At her 3-month postoperative checkup, her active forward flexion, neutral external rotation, and abduction were 165 degree, 70 degree and 130 degree, respectively. The patient had no pain with shoulder motion in any plane, and her external rotation strength at neutral was 5/5. The patient progressed through physical therapy without significant difficulty. Histologic analysis of the loose bodies was revealed to have reactive changes and with areas of tissue necrosis This was noted to be atypical of synovial or bursal tissue. Cultures were negative for bacterial or fungal growth. Also reported as, our patient had the unique finding of hardened, chalklike flakes that represented reactive changes and fibrinoid necrosis It is likely that this was the resultant effect of inadvertent injection of influenza vaccine into the subacromial bursa.  On an unspecified date, the patient recovered from the events of 'soft tissue necrosis', 'bursitis', 'foreign body reaction', 'impingement syndrome' and 'shoulder injury related to vaccine administration'.  The reporter assessed the events of 'soft tissue necrosis', 'bursitis', 'foreign body reaction', 'impingement syndrome' and 'shoulder injury related to vaccine administration' as related to influenza virus vaccine polyvalent. It is likely that this was the resultant effect of inadvertent injection of influenza vaccine into the subacromial bursa.  The event of 'soft tissue necrosis' was considered to be medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.  In conclusion, SIRVA is an uncommon complication of deltoid vaccine administration that can present with symptoms and imaging that mimic other etiologies of shoulder dysfunction. Failed conservative management could be treated with arthroscopic shoulder debridement of inflamed soft tissue and bone, while obtaining cultures and pathology to rule out infection. In addition, we recommend postoperative physical therapy to achieve functional and symptomatic recovery.  Company comment: A 51-year-old patient was vaccinated with influenza virus vaccine polyvalent, inadvertently administered into the subacromial bursa. Reportedly, it was traumatic experience due to multiple redirections of the needle while injecting the vaccine. Over 48 hours after receiving vaccine, the patient developed severe shoulder pain and weakness. On an unknown date, 12 weeks after receiving influenza virus vaccine polyvalent, the patient reported 3 months of severe right shoulder pain. The patient diagnosed with rotator cuff bursitis and impingement syndrome. In addition, the patient had the unique finding of hardened, chalklike flakes that represented reactive changes and fibrinoid necrosis. Causality was highly confounded by inappropriate administration, however causal role of the vaccine cannot be excluded and is assessed as possibly related. Product administration error and Product administered at inappropriate site are assessed as unrelated per company's conventions. (defaults to related in the safety database for reporting purposes).; Reporter's Comments: The reporter assessed the events of 'soft tissue necrosis', 'bursitis', 'foreign body reaction', 'impingement syndrome' and 'shoulder injury related to vaccine administration' as related to influenza virus vaccine polyvalent. It is likely that this was the resultant effect of inadvertent injection of influenza vaccine into the subacromial bursa.; Sender's Comments: A 51-year-old patient was vaccinated with influenza virus vaccine polyvalent, inadvertently administered into the subacromial bursa. Reportedly, it was traumatic experience due to multiple redirections of the needle while injecting the vaccine. Over 48 hours after receiving vaccine, the patient developed severe shoulder pain and weakness. On an unknown date, 12 weeks after receiving influenza virus vaccine polyvalent, the patient reported 3 months of severe right shoulder pain. The patient diagnosed with rotator cuff bursitis and impingement syndrome. In addition, the patient had the unique finding of hardened, chalklike flakes that represented reactive changes and fibrinoid necrosis. Causality was highly confounded by inappropriate administration, however causal role of the vaccine cannot be excluded and is assessed as possibly related. Product administration error and Product administered at inappropriate site are assessed as unrelated per company's conventions. (defaults to related in the safety database for reporting purposes).