Acute calcific tendinitis of the longus colli muscle: spectrum of CT appearances and anatomical correlation

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1 The British Journal of Radiology, 82 (2009), e117 e121 CASE REPORT Acute calcific tendinitis of the longus colli muscle: spectrum of CT appearances and anatomical correlation C E OFFIAH, BSc, FRCS, FRCR and E HALL, MB, ChB Barts and the London Hospitals NHS Trust, The Royal London Hospital, Whitechapel, London E1 1BB, UK ABSTRACT. Calcific tendinitis of the longus colli muscle is a retropharyngeal inflammatory process of the named prevertebral muscle that can present acutely with debilitating symptoms. The cross-sectional imaging appearances of this rare condition, although rather specific, can be somewhat misleading. This is, in part, due to a lack of familiarity with the normal anatomy and pathology of the prevertebral space, as well as the variation in the imaging appearances that can be found. Definitive radiological diagnosis is often paramount to avoid unnecessary and potentially dangerous intervention. Three cases of acute calcific tendinitis of the longus colli muscle are presented, with the salient anatomy and variation in CT appearances described. Received 5 March 2008 Accepted 3 June 2008 DOI: /bjr/ The British Institute of Radiology Calcific tendinitis of the longus colli muscle is a retropharyngeal inflammatory process that affects the named cervicothoracic prevertebral musculature. The cross-sectional imaging appearances, although often confirmatory of the diagnosis, can be somewhat misleading in this sporadically reported and rarely encountered condition. Occasionally, a more sinister neoplastic aetiology is suggested by ill-informed radiologists and clinicians for what is, in fact, a benign condition that commonly settles with conservative management despite its rather debilitating symptoms. Some of the misdiagnosis of this condition on cross-sectional imaging usually CT relates to the variations in retropharyngeal appearance that can occur at imaging. Three cases of acute calcific tendinitis of the longus colli muscle identified on CT imaging are presented along with their correlative clinical presentations and subsequent outcome, which demonstrate the variability of imaging appearances from subtle, through to moderate, and finally very marked that should assist in alerting the radiologist to the potential diagnosis. Case 1 A 37-year-old woman presented to the Emergency Room with a 10-day history of neck pain and stiffness, moderate discomfort on swallowing and occipital headache. Limited neck movement was noted on examination and the occipital region and posterior neck were found to be tender. The patient denied any history of trauma and there was no evidence of current or recent upper respiratory tract infection. Despite this, she was found Address correspondence to: C E Offiah, Barts and the London Hospitals NHS Trust, The Royal London Hospital, Whitechapel, London E1 1BB, UK. curtis.offiah@bartsandthelondon. nhs.uk to have a low-grade pyrexia of 37.5 C. Inspection of the oropharynx demonstrated some excess pooling of saliva that obscured satisfactory posterior visualisation. Full blood count and blood biochemistry were unremarkable. Given the clinical presentation and examination findings, a contrast-enhanced CT of the neck was performed (Figure 1). This revealed small flecks of globular calcification in the right longus colli muscle predominantly at the C2 C3 level; the muscle was swollen and oedematous throughout most of its extent and a small retropharyngeal effusion was evident. A diagnosis of acute calcific tendinitis of the longus colli was made and the patient treated conservatively with non-steroidal antiinflammatory drugs and physiotherapy. The patient s symptoms resolved completely over the course of 2 weeks, at which point she was subsequently discharged from further follow-up. Case 2 A 66-year-old woman presented to the accident and emergency department 2 weeks after a low-velocity road traffic accident in which she was the front-seat passenger and sustained a mild whiplash injury; she complained of neck pain, dysphagia and odynophagia, which had developed slowly over the 2-week period. Limited neck movement was noted on examination but there was no point tenderness over the cervical spine. She was apyrexial and her cardiorespiratory examination was unremarkable. Nevertheless, she was referred to the general medical physician on call, who was concerned about possible vertebral artery dissection injury resulting from the whiplash injury, and so a CT angiogram of the neck vessels and circle of Willis was undertaken (Figure 2). The extracranial and intracranial anterior and posterior circulations were normal; specifically, there was no evidence of dissection abnormality of the e117

2 C E Offiah and E Hall Figure 1. Acute calcific tendinitis of the right longus colli muscle. (a d) on bone and soft-tissue algorithms with a sagittal (right parasagittal) reformat on bone windows demonstrating a small focus of calcification related to the superior tendon fibre location of the right longus colli muscle. (c) A small retropharyngeal space effusion is noted. extracranial vertebral arteries. However, a moderatesized focus of amorphous calcification was demonstrated in the right longus colli muscle centred on the C1 C2 level, which was associated with some oedema and local mass effect on the overlying oropharyngeal mucosa. A diagnosis of calcific tendinitis of the right longus colli muscle was made. The patient was discharged to outpatient follow-up with conservative treatment; her symptoms had completely resolved by the time of her 6-week follow-up appointment. Figure 2. Acute calcific tendinitis of the right longus colli muscle. (a,b) on soft-tissue and bone windows obtained as part of a CT angiographic study on a patient with neck pain a few days after a minor whiplash injury. There is a large focus of globular amorphous calcification in the location of the superior tendon fibres of the right longus colli muscle. Local mass effect on the right side of the posterior wall of the oropharynx is present as a result of the concomitant swelling. e118

3 Case report: Acute calcific tendinitis of the longus colli muscle Figure 3. Acute calcific tendinitis of the left longus colli muscle. (a d) on soft-tissue and bone algorithms. The relationship of the calcification to the superior tendon fibres is well demonstrated at this level. The large area of prevertebral amorphous calcification is evident slightly more inferiorly (b,d) and is quite marked in comparison to Case 1 (see Figure 1). Case 3 A 51-year-old man presented to his general practitioner (GP) with a 3-day history of worsening neck pain and the feeling of a lump in the left side of his throat with some hindrance to swallowing, particularly of solid foods. There was no recent history of upper respiratory tract infection and no relevant past medical history. The GP could find no abnormality on examination of the oropharynx. The patient was referred to the Ear Nose and Throat service, who confirmed the clinical findings and, following discussion with the radiologist, referred the patient for a contrast-enhanced CT examination of the neck. This revealed an abnormal area of amorphous globular calcification in the left longus colli muscle at the C1 C2 level and resultant fullness of the left oropharynx (Figure 3). A diagnosis of calcific tendinitis of the left longus colli muscle was given. The patient s symptoms resolved completely over the course of 2 weeks with conservative management. Discussion A significant part of the prevertebral space is composed of the paired longus colli muscles which, together with the adjacent paired longus capitis muscles, are flexors of the neck. Despite their rather understated existence, the longus colli muscles are important in relation to head and neck and spinal pathology not only because of their close relationship to the retropharyngeal space and deep (prevertebral) layer of the deep cervical fascia but also their extensive craniocaudad attachment to the osseous cervicothoracic spine [1 4]. The longus colli muscle extends from the level of the anterior tubercle of the atlas into the superior mediastinum to the level of the T3 vertebral body (Figure 4); it consists of superior (upper oblique), central (vertical) and inferior (lower oblique) fibres. The superior fibres attach the anterior tubercle of the atlas to the anterior tubercles of the transverse processes of C3 C5 vertebrae; the inferior fibres connect the bodies of T1 T3 vertebrae to the anterior tubercles of the transverse processes of C5 C6 vertebrae; the central fibres attach the bodies of C2 C4 vertebrae to the remaining cervical and upper three thoracic vertebrae. This muscle, together with the adjacent superiorly related overlying longus capitis muscle, is a weak flexor of the neck weak because it is aided by gravity and the more powerful sternocleidomastoid muscle [1, 2]. It is the superior tendon fibres of the longus colli muscle that are affected in acute calcific tendinitis. e119

4 C E Offiah and E Hall Figure 4. Anatomical illustration of the parts, origin and insertion of the longus colli muscles and their relationship to the prevertebral compartment. (Reproduced with permission from Stranding et al [2].) The longus colli muscle is covered by the prevertebral layer of the deep cervical fascia and is separated from the potential retropharyngeal space by the alar and prevertebral layers of the deep cervical fascia [1 4] Acute calcific tendinitis of the longus colli muscle is an infrequently encountered pathology that is probably underdiagnosed and, given its rather startling crosssectional imaging appearances in the more extreme cases (Figure 2), can prompt misdiagnosis. The condition was first described in 1964 by Hartley [5] and now goes under a number of synonyms, including acute retropharyngeal calcific tendinitis and calcific prevertebral tendinitis. However, these synonyms fail to highlight the specific anatomical structure involved (the longus colli muscle tendon), which is key to establishing the diagnosis on imaging, and so we feel that the full title is preferred. Hartley [5] described a case of acute onset of neck pain and stiffness associated with odynophagia, which on plain film radiography demonstrated prevertebral swelling associated with amorphous calcification anterior to the C2 vertebral body. Ring et al [6] reported on five patients in whom an initial misdiagnosis of this condition led to unnecessary medical treatment and, in one case, unnecessary open biopsy. It was the histological and subsequent polarised light microscopy and electron microscopy examinations of this biopsy, however, that revealed the histopathological basis of this condition. Intratendinous calcium granulomatous lesions were identified on routine light microscopy; polarised light and electron microscopy confirmed that the foreign body inflammatory response was caused by the deposition of crystals of calcium hydroxyapatite. Pathological deposition of calcium hydroxyapatite crystals in tendinous and other periarticular tissues is recognised in other areas of the body, but most notably the shoulder in supraspinatus tendinopathy; a similar pathological abnormality has been identified in the wrist, hip and ankle [7]. The typical demographic of acute calcific tendinitis of the longus colli muscle is of a male or female patient usually in their third to sixth decade of life [8], although patients as young as 21 years of age and as old as 81 years of age have been identified [9]. Patients complain of rather acute onset of neck pain and stiffness progressing over a period of several days, as well as odynophagia and dysphagia. Clinically, there may be limited neck movement and a low-grade pyrexia; mild elevation of the erythrocyte sedimentation rate associated with a mild leukocytosis may be identified infrequently on haematological analysis. A discernible history of recent upper respiratory tract infection or minor neck trauma is variable [7 13]. The imaging modality of choice for confirmatory radiological diagnosis of acute calcific tendinitis of the longus colli muscle is CT owing to its enhanced contrast resolution and the multiplanar capabilities of newer multidetector scanners; the original reports of this condition pre-dated CT and utilised plain film radiography [5, 6, 13]. However, plain film radiography may miss subtle calcification within the tendon. MRI detects inflammation involving and surrounding the longus colli muscle but its representation of calcification is inferior to that of CT [6, 8]. A technetium-99m diphosphonate bone scan has proved unhelpful in this condition [6]. e120

5 Case report: Acute calcific tendinitis of the longus colli muscle Paramount to establishing the correct radiological diagnosis of acute calcific tendinitis of the longus colli muscle is knowledge of the normal anatomy of the prevertebral cervicothoracic musculature. It is the superior fibres of the longus colli muscle tendons that are predisposed (at the C1 C2 level) to the typical amorphous calcification. The degree of calcification can be extremely variable, as indicated by the present review, and in certain cases rather subtle (e.g. Case 1); the severity of symptoms does not appear to correlate particularly well with the degree of calcium deposition identified on CT. In addition, symptomatically, all three cases in the present study resolved completely following conservative treatment despite the variability in the degree of macroscopic calcium hydroxyapatite deposition demonstrated. Secondary features can aid radiological diagnosis, most notably small retropharyngeal effusions and oedematous swelling of the adjacent prevertebral soft tissues. The traces of retropharyngeal space fluid are well demonstrated on MRI given the excellent soft-tissue contrast provided by this modality [8, 11]; however, these effusions are readily discernible on modern CT scanner protocols. Mihmanli et al [8] have reported a case of acute calcific tendinitis of the longus colli muscle with suggested localised marrow signal inflammatory change in the anterior arch of C1 and the body of C2, which subsequently resolved together with the prevertebral changes following conservative treatment. No correlative bone changes have ever been reported on CT assessment, and none was evident in the presented cases. Awareness of the existence of this condition, as well as awareness and recognition of its characteristic radiological features, are key to averting unnecessary interventions both medical and surgical. Erroneous radiology-led diagnoses, such as suppurative retropharyngeal infection, fracture dislocation of the cervical spine, myositis ossificans and primary or metastatic neoplasia (e.g. rhabdomyosarcoma), are frequently proposed by uninitiated radiologists to account for the imaging appearances [6, 11]. The correct imaging diagnosis is assisted by attention to (i) the presence of pathognomonic calcification in the superior tendon fibres of the longus colli muscle, (ii) the presence of fluid within the retropharyngeal space but no associated enhancement around the effusion to suggest abscess formation, (iii) the absence of suppurative or nonsuppurating inflammatory retropharyngeal lymph nodes, (iv) the absence of any bony destructive change to the adjacent cervical spine vertebrae, and (v) recognition of the striking variability in the degree of tendinous calcium deposition in the affected muscle tendon, which may range from subtle to the more typical marked globular amorphous appearance despite the relative lack of variability in the severity of clinical symptoms. The management of acute calcific tendinitis of the longus colli muscle is conservative: the vast majority of patients symptoms and signs resolve over the course of a few weeks with non-steroidal anti-inflammatory drugs and physical rest. Occasionally, steroids have been utilised. Conclusions Acute calcific tendinitis of the longus colli muscle is an infrequent entity. However, knowledge of its existence, as well as awareness of its radiological appearances, particularly on CT, is crucial to avoid unnecessary medical and surgical intervention. The variability in the severity of CT appearances of the condition has been highlighted in the present study in order to assist in the recognition and establishment of the correct radiological diagnosis. References 1. McMinn RMH. Head and neck and spine. In: McMinn RMH, editor. Last s anatomy: regional and applied. Edinburgh, UK: Churchill-Livingstone; 1994: Stranding S, Healy J, Johnson D, Williams A. Neck and upper aerodigestive tract. 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