1. Longus colli tendinitis mimicking a retropharyngeal abscess in a 12 year old girl.
CA Hilditch1, S Biswas2, S Mathur1
1. Departments of Neuroradiology
Lancashire Teaching Hospitals NHS Foundation Trust
Preston, UK
2. The Walton Centre, NHS Foundation Trust
Liverpool, UK

2. Purpose
To demonstrate the diagnostic dilemma caused by a rare case of longus colli tendinitis presenting as a retropharyngeal abscess with unique imaging features

3. Case report: Clinical
A 12 year old girl with no significant past medical history presented to the emergency department complaining of severe neck pain
On examination:
Marked restriction of neck movements with severe pain
Pyrexia
Redness and swelling of the left side of the neck
Mild trismus and swallowing difficulty due to pain
Blood biochemistry showed raised inflammatory markers and a neck ultrasound demonstrated reactive lymphadenopathy

4. Plain film
Plain films of the neck show some prevertebral soft tissue swelling but no evidence of calcification

5. Ultrasound
Ultrasound scanning of the neck showed reactive lymphadenopathy only

6. Axial & Coronal T2W MRI Neck
Urgent neck MRI showed an inflammatory collection in the left prevertebral soft tissues, confined to the left longus colli muscle

7. MRI Neck T1W
Add images in best plane showing ?3 tiny enhancing lesions
Irregular thick walled fluid collection in the left longus colli muscle

8. MRI Neck T1+C
Fat saturated T1 post contrast MRI showed a large irregular rim enhancing inflammatory mass in the prevertebral soft tissues within the left long colli muscle

9. Initial diagnosis
Retropharyngeal abscess

10. Further investigations & management
Surgical neck exploration
No drainable abscess identified
Biopsy of the post nasal space
Reactive hyperplasia
Commenced on IV antibiotics
Remained an inpatient for 10 days

11. Clinical improvement and discharged home with a course of oral antibiotics

12. Follow-up MRI at 1 month
Axial fat saturated T1 pre and post contrast demonstrates marked improvement with some mild residual enhancement in the left longus colli muscle

13. Longus colli tendinitis
Acute calcific tendinitis of the longus colli muscle is a rare condition that causes severe neck pain (1).
Calcium hydroxyapatite crystals are deposited causing acute inflammatory changes in the muscle.
Benign condition that usually mimics more serious causes of acute neck pain such as retropharyngeal abscess, meningitis and infectious spondylitis (2).

14. Longus colli tendinitis
Classic imaging findings of calcification in the prevertebral soft tissues on CT and plain film may not be present (3).
Longus colli tendinitis can present with a retropharyngeal effusion/fluid collection which can mimic retropharyngeal abscess (4, 5)
To our knowledge this is the first case diagnosed in a child and with a fluid collection displaying a thickened irregularly enhancing wall confined to the longus colli muscle
Longus colli tendinitis is an important condition to recognise as it can be treated conservatively and usually will resolve with symptomatic treatment after 1 to 2 weeks.
Early diagnosis can prevent unnecessary invasive management or investigations such as neck surgery and biopsy
Longus colli tendinitis can have a range of imaging appearances and should be suspected in cases of lesions confined to the longus colli muscle
Tissue from which sites?
Is muscle a key target?

15. Longus colli tendinitis; classic imaging findings (6)
Foci of amorphous calcification within the superior fibres of the longus colli tendon are typical. Non contrast enhanced CT is the imaging modality of choice.
Images taken from; OFFIAH CE, HALL E. Acute calcific tendinitis of the longus colli muscle: spectrum of CT appearances and anatomical correlation. British Journal of Radiology 2009 June;82(978):e121.

16. Take home points
Longus colli is a rare condition which can mimic serious causes of neck pain and stiffness
Classic calcifications in the superior fibres of the longus colli muscle tendon may not be present
The finding of a retropharyngeal fluid collection smoothly enlarging the retropharyngeal space should prompt the radiologist to search for calcifications in the longus colli tendon (4)
The diagnosis should be considered when there is absence of compelling imaging or clinical evidence of acute bacterial infection (4)
Early recognition can prevent unnecessary invasive surgery
The condition usually settles within weeks with conservative management with anti-inflammatory medications

17. References
1) Estimable K, Rizk C, Pujalte GGA. A rare case of neck pain: acute longus colli calcific tendinitis in a possibly immunocompromised individual. Journal of the American Board of Family Medicine : JABFM 2015 January;28(1):
(2) Shin D, Ahn C, Choi J. The Acute Calcific Prevertebral Tendinitis: Report of Two Cases. Asian Spine Journal 2010 December 1;4(2):
(3) Kang C, Son ES, Kim DH, Jang H. Acute Longus Colli Tendinitis without Calcification. Journal of the Korean Orthopaedic Association 2015 June 1;50(3):
(4) Eastwood JD, Hudgins PA, Malone D. Retropharyngeal effusion in acute calcific prevertebral tendinitis: diagnosis with CT and MR imaging. American Journal of Neuroradiology 1998 October 1;19(9):1789.
(5) Ronak Rahmanian, Chris Diamond. Calcific Tendonitis of the Longus Colli Muscle: A Noninfectious Cause of Retropharyngeal Fluid Collection. Case reports in otolaryngology 2014;2014:
(5) OFFIAH CE, HALL E. Acute calcific tendinitis of the longus colli muscle: spectrum of CT appearances and anatomical correlation. British Journal of Radiology 2009 June;82(978):e121