Clinical History
A 55-year-old woman presented with acute posterior neck pain and cervical stiffness. There was no history of trauma. Biochemical analysis was normal, except for a mild increase of erythrocyte sedimentation rate (ESR = 30mm/h). No other clinical impairment, including history of fever, was documented.
Imaging Findings
Cervical en face and lateral radiograms were performed showing mild cervical degenerative discopathy between C5-C6, with subchondral platform sclerosis and irregularity, associated with narrowing of disk space (Fig. 1 a, b). No other changes were noted.
A complementary cervical spine CT was performed. Unenhanced CT confirmed the degenerative changes between C5-C6, but also revealed a retropharyngeal space fluid collection and coarse calcifications located anterior to C1 and C2 (Fig. 2a-d).
Discussion
The longus colli muscle is located in the prevertebral area and consists of three parts: upper oblique, vertical and lower oblique fibres. Acute calcific tendinitis of the longus colli (also known as calcific retropharyngeal tendinitis and calcific prevertebral tendinitis) is a self-limiting inflammatory condition that involves the upper oblique fibres insertion, secondary to deposition of calcium hydroxyapatite crystals at the C1–C3 vertebral level [1]. The exact aetiology of calcium hydroxyapatite crystals deposition is not well known, but repetitive trauma, ischaemia, necrosis and tendinous degeneration are some of the hypotheses mentioned [1, 2].
The true incidence of the disease is still unknown, but it may be a subdiagnosed entity [3].
The characteristic triad of symptoms consists of acute posterior neck pain, neck stiffness and dysphagia or odynophagia. Haematological analysis may show mild elevation of erythrocyte sedimentation rate (ESR) accompanied by low-grade pyrexia and mild leukocytosis. Furthermore, dysphagia, sore throat, limited range of neck motion, pharyngeal oedema, erythema of nasopharynx and neck spasm may be associated with this entity [1].
CT is the gold standard for identifying the presence of oedema and calcific deposition, two determinant findings in establishing the diagnosis of retropharyngeal tendinitis [1, 4, 5].
MRI can show the prevertebral oedema and corresponding fluid effusion, but one will not easily recognize the calcific deposits [4].
On plain radiography the calcium deposition and the prevertebral soft-tissue swelling may also be missed [1, 4].
The most important mimicker of longus colli tendinitis is retropharyngeal abscess [1, 3]. These two entities can be differentiated with a CT examination, revealing the characteristic calcareous deposition at the C1–C3 vertebral level [1, 4-6].
Acute calcific tendinitis of the longus colli muscle tends to be a self-limiting disease [1]. Non-steroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment, but in severe cases, steroids or opioids may be added. Immobilization with soft cervical collar is another useful method to avoid aggravation of symptoms [1].
The symptoms usually begin to resolve within a couple of days from the initiation of treatment and the patients become symptom-free after 1–3 weeks [1].
Knowledge of the characteristic imaging findings of this underreported disease is essential for early diagnosis and differentiation from other acute conditions, namely retropharyngeal abscess, thus avoiding unnecessary invasive procedures [6, 7].
Differential Diagnosis List
Calcific tendinopathy of the longus colli
Retropharyngeal abscess
Retropharyngeal cellulitis
Calcified tendinopathy
Branchial cleft infected cyst
Final Diagnosis
Calcific tendinopathy of the longus colli
