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Introduction

  1. Top of page
  2. Introduction
  3. Case reports
  4. Discussion
  5. REFERENCES

Calcium phosphate crystal deposition diseases are caused by the formation of calcium pyrophosphate dihydrate (CPPD) crystals and basic calcium phosphate (BCP) crystals in joints and periarticular tissues (1, 2). CPPD crystalline deposits usually occur in the midzone of hyaline cartilage in close association with hypertrophic chondrocytes and are rarely seen in tendons or bursae (3–5). In contrast, BCP crystals, consisting of carbonate-substituted hydroxyapatite, octacalcium phosphate, and dicalcium phosphate dihydrate, remain the most commonly identified crystals associated with calcific bursitis and tendinitis, as well as with periarticular calcifications and severe osteoarthritis (3). Other less common clinical manifestations of BCP crystal deposition disease include acute arthritis and destructive arthropathies, such as hemorrhagic senile shoulder (Milwaukee shoulder or rotator cuff arthropathy) (6). CPPD crystal deposition disease is clinically associated with an acute episodic mono- or oligoarthritis, termed pseudogout, involving a large joint (including the knees, wrists, and ankles) or a chronic arthropathy manifesting as mild joint pain and stiffness of knees, wrists, metacarpophalangeal joints, elbows, and shoulders (1, 2). Less commonly, pyrophosphate tophaceous deposits have been observed around peripheral joints and in the spine, including the intervertebral disc, posterior longitudinal ligament, facet joints, ligamentum flavum, and sacroiliac joint (7–9). In the cervical spine, calcified deposits in the ligamentum flavum, facet joints, lateral masses, and posterior longitudinal and atlantoccipital ligaments can be associated with signs of spinal stenosis, meningismus, and cervical myelopathy (9, 10).

Neck pain due to calcifications surrounding the odontoid process were described by Bouvet et al in 1985 and termed crowned dens syndrome (CDS) (11). They described 4 women who experienced neck pain and underwent tomographic examination revealing radioopaque densities surrounding the top and sides of the odontoid process in a crown- or halo-like distribution. It was postulated that the crowned dens deposits could be attributed to hydroxyapatite crystals as well as CPPD crystals. Here, we present 2 additional cases of severe neck pain associated with CDS: the first case mimicking metastatic bone disease of the cervical spine, and the second case mimicking temporal arteritis.

Case reports

  1. Top of page
  2. Introduction
  3. Case reports
  4. Discussion
  5. REFERENCES

Case 1.

A 56-year old woman presented with a 6-month history of progressive neck pain. At the onset of these symptoms, she had a chiropractic manipulation of the cervical spine that was not helpful, and the patient experienced gradually progressive pain and decreased range of motion. Review of systems revealed arthralgias of the hands and knees. There was no history of trauma or focal motor or sensory abnormalities, and no changes in bowel or bladder function. Her medical history was significant for right breast cancer 10 years previous. She had undergone a right mastectomy and reconstruction and yearly subsequent mammograms were normal. On musculoskeletal examination, passive rotation of the neck was limited to 45° to the left and right and she had mild limitation of extension and flexion. Minimal tenderness at the extremes of range of motion was noted; there was no point tenderness along the spine and paraspinal muscles. Examination of the hands showed no evidence of synovitis, though the first carpometacarpal joint showed bony enlargement as well as Heberden's nodes. Neurologic examination was unremarkable.

Due to the patient's history of breast cancer and concern for metastatic disease, a cervical spine magnetic resonance image (MRI) was obtained that revealed enhancement of the odontoid process and adjacent soft tissues (Figure 1A). No abnormal signal was seen within the spinal cord and there was no evidence of disc herniation, central canal stenosis, or foraminal stenosis. A bone scan showed a focus of increased radionuclide uptake at the odontoid process suspicious for metastasis (Figure 1B). Other areas of increased radionuclide uptake in the left hip, both shoulders, both thumb bases, and the C6 vertebral body were suggestive of degenerative joint disease. Cervical spine radiographs with an odontoid view revealed poorly defined calcifications adjacent to the odontoid process (Figure 1C), and the lateral view revealed atlantoaxial joint space narrowing with no evidence of a destructive or lytic lesion. Axial computed tomography (CT) images also revealed narrowing of the atlantoaxial joint and foci of increased densities surrounding the odontoid. Coronal reformatting of axial images showed sclerosis of the odontoid process and atlantoaxial synovial calcifications in a crown- or halo-like distribution around the odontoid process (Figure 1D), characteristic of CDS. There was no evidence of osseous destruction, lytic lesions, or fractures. Hand radiographs showed osteoarthritis without calcification of the triangular ligament or chondrocalcinosis. The patient was treated with nonsteroidal antiinflammatory medications and physical therapy with gradual resolution of symptoms. Followup imaging at 6 (MRI) and 12 months (CT) showed no evidence of destructive lesions to suggest metastasis at C1-2.

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Figure 1. A, Sagittal fat-suppressed T1-weighted magnetic resonance image after intravenous injection of Gd-DTPA showing edematous changes of odontoid bone marrow and surrounding soft tissues (arrows). Calcifications shown as areas of low signal intensity between odontoid and posterior longitudinal ligament (arrowhead). B, Static image of radionuclide bone scan (Tc 99m MPD) showing increased uptake in the region of odontoid (arrow). C, Sagittal reformatted computed tomography (CT) image of cervical spine shows marked narrowing of atlantoaxial joint space (arrowheads) and sclerosis of odontoid (arrow). D, Coronal reformatted CT image reveals crown-shaped calcifications surrounding odontoid process (arrows).

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Case 2.

A 73-year-old man with a medical history significant for hypertension, hypercholesterolemia, prostate cancer, and pulmonary embolism was admitted to the hospital with a 6-week history of right-sided temporal and occipital headache associated with neck and right shoulder pain. Symptoms started initially with right shoulder pain and spread to the neck and scalp. The pain was worst at night and associated with difficulty moving the neck. Additionally, the patient felt intermittent swelling in the right temporal region with right ear numbness and jaw claudication. He denied fevers and visual symptoms. Review of systems was remarkable for weight loss following partial colectomy and colostomy 5 months prior for radiation-induced colitis. Initial evaluation showed an elevated erythrocyte sedimentation rate (ESR) and C-reactive protein level to 100 mm/hour and 12 units, respectively. The patient was started on 60 mg of prednisone for presumptive temporal arteritis 2 weeks prior to admission, with no improvement in his symptoms. Examination revealed mild tenderness over the right temporal and occipital regions, but temporal arteries were normal. Examination of the neck showed right cervical paraspinal muscle spasm and limited range of motion of flexion, extension, and lateral rotation. Range of motion of other joints, including the shoulders, was normal and no synovitis was detected. Radiographs and CT of the cervical spine showed diffuse degenerative disc disease with osteophyte formation and neural foraminal encroachment from C3-4 through C6-7. Amorphous calcifications were identified in soft tissues adjacent to the odontoid characterizing CDS (Figure 2A and 2B). The patient had a temporal artery biopsy that was negative. CT scan of the chest showed a lung mass and biopsy confirmed the diagnosis of bronchogenic carcinoma of the lung. The prednisone dosage was tapered and the patient was started on nonsteroidal antiinflammatory medication.

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Figure 2. Axial (A) and reformatted coronal (B) CT images at level of C1-2 show calcifications affecting atlas transverse ligament (arrowheads) and soft tissues surrounding odontoid (arrows). Multiple metastatic lesions were observed in the vertebrae (not shown).

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Discussion

  1. Top of page
  2. Introduction
  3. Case reports
  4. Discussion
  5. REFERENCES

We have presented 2 cases of neck pain mimicking metastatic cancer and temporal arteritis, respectively, which were subsequently diagnosed as the crowned dens syndrome. CDS was described by Bouvet et al in 1985 as neck pain caused by deposition of hydroxyapatite or CPPD crystals in the cervical spine and appearing radiographically as radioopaque densities surrounding the top and sides of the odontoid process in a crown- or halo-like distribution (11). In addition to the 4 cases described by Bouvet and the 2 cases presented in this series, we identified 11 additional cases in the English literature via Medline and PubMed database searches and citations from relevant articles (11–15). All patients presented with neck pain though duration of symptoms ranged from acute to several years. In our case series, patient 1 presented with chronic symptoms of 6 months whereas patient 2 presented with subacute symptoms of 6 weeks duration. Seven of the patients in the literature had documented fevers or elevated ESR. Although plain radiography is useful in the detection of chondrocalcinosis in the appendicular skeleton, CT scans confer greater sensitivity and are particularly advantageous in the spine, where chondrocalcinosis has been reported to occur within the intervertebral discs, in the ligamentum flavum, and in the interspinal ligmaments (16, 17). Accordingly, CT scanning was the preferred modality of imaging in the majority of cases, including the 2 patients described above. Of the 17 cases of CDS, only 1 was confirmed by tissue diagnosis from the cervical spine due to progressive neurologic symptoms (14). Microscopic examination of the removed mass revealed the presence of CPPD crystals within the fibrous tissue and chronic inflammatory changes (14). In most of the other cases, the diagnosis of CPPD was supported by radiographic evidence of chondrocalcinosis of appendicular joints, most commonly shoulders, hips, and knees. Four cases were further supported by arthrocentesis and demonstration of CPPD or hydroxyapatite crystals (11). The mainstay of medical treatment of neck pain due to CDS has been nonsteroidal antiinflammatory drugs with generally prompt resolution of symptoms, though up to 2 months of therapy was necessary in 4 cases (11, 14), including one of our patients.

Although CDS appears radiographically as calcific deposits surrounding the top and sides of the odontoid process, other locations of calcium crystal deposition in the cervical spine have been described. There are several reports of compressive cervical myelopathy caused most commonly by CPPD deposition of the ligamentum flavum (10, 18–20). Additionally, several groups have reported case series of CPPD crystal deposition of the periodontoid region, most commonly of the transverse ligament of the atlas (17, 21–27). Periodontoid CPPD crystal deposition was demonstrated by Dirheimer et al (22) in a study in which 27 neurologically asymptomatic patients with articular chondrocalcinosis were imaged by cranial-cervical junction X-ray polytomography. Twelve patients (44%) were found to have syndesmoodontoid joint calcification. More recently, Constantin et al (24) reported on axial CT scanning of the cervical-occipital hinge of 21 patients with articular chondrocalcinosis. Fourteen patients were found to have calcification of the transverse ligament of the atlas, including all 5 patients with acute neck pain. It has been postulated that CPPD deposition of the atlantoaxial joint can be explained by the presence of chondroid cells within the transverse ligament of the atlas, thus rendering it structurally analogous to the meniscus of the knee, a fibrocartilaginous structure (24). Others have suggested that fibroblasts within cervical spine ligaments can transform into chondrocytes, thus making these ligaments susceptible to calcification (28, 29). Hydroxyapatite crystal deposition has also been reported in other areas of the cervical spine, including deposition in the longus coli muscle causing calcific tendinitis of the neck, as well as deposition in cervical intervertebral discs and the ligamentum flavum (18, 30, 31).

As suggested by Bouvet et al (11), the radiographic localization of calcium deposition in CDS suggests involvement of the cruciform ligament, a ligament located posterior to the odontoid in the form of a cross, with the horizontal bar formed by the transverse ligament of the atlas and the vertical bars formed by the superior and inferior longitudinal fascicles. It is quite possible that some of the patients in the case series describing CPPD deposition of the transverse ligament of the atlas and the ligamentum flavum represent cases of CDS as well.

In summary, CDS is a clinical-radiologic entity consisting of neck pain and cervical spine calcium crystal deposition with CT scan demonstrating densities surrounding the top and sides of the odontoid process in a crown- or halo-like distribution (11). This syndrome, along with calcium crystal deposition of the cervical spine in general (including the transverse ligament of the atlas and ligamentum flavum) can mimic meningitis (32), osteomyelitis (33, 34), degenerative cervical spine disease, ankylosing spondylitis (35), gout (36, 37), rheumatoid arthritis (38), temporal arteritis, metastatic bone disease (39, 40), and spinal tumors (41). CDS is an important consideration in the differential diagnosis of neck pain.

REFERENCES

  1. Top of page
  2. Introduction
  3. Case reports
  4. Discussion
  5. REFERENCES