Annals ofthe Rheumatic Diseases, 1983, 42, 350-353

Case report

Spondylodiscal erosions due to gout:anatomico-radiological study of a case

R. LAGIER' AND W. MAC GEE2

From the 'Department ofPathology (Osteoarticular Unit), and the 2Department ofMedicine (GeriatricsHospital), Faculty ofMedicine, Geneva, Switzerland

SUMMARY The necropsy of an 84-year-oldwoman with painful polyarticular gout showed asevere erosion of the L2 vertebral body due tosodium urate deposition. The radiological signsof this tophus had existed for many years; it hadcaused recurrent pain but no neurological com-plications. A small tophus and a Schmorl's nodeon 2 neighbouring thoracic vertebrae permittedthe differentiation between vertebral plate ero-sion in the first, which was of bone origin, andvertebral plate remodelling in the second, whichoriginated in the cartilaginous tissue of the disc.

Spinal pain in sufferers from gout has often beennoted. However, only on rare occasions has it beenshown that a vertebral lesion was due to a tophus. In arecent radiological study of the spine in 275 subjectswith gout aged from 21 to 84 years Kawenoki-Minc etal.' observed only one case of vertebral erosion; thiserosion, which was confirmed at necropsy, was in thecervical region. Other studies have shown lesionspredominantly in the discovertebral region but alsoaffecting the articular surfaces of the posterior inter-vertebral joints2 and the spinal canal (in the extra-dural position), with urate deposition sometimesinvolving the ligamenta flava and possibly associatedwith neurological complications.3?5

Case report

The family history of this woman, a former gymnas-tics instructor, was unremarkable. She was alcoholic,obese, but nondiabetic. When she was about 65 painin the limb joints associated with lumbago appeared.The symptoms became worse, sometimes with sharplumbar pains, 12 years later. This lead to a diagnosisof gout based on an increased serum uric acid levelAccepted for publication 22 April 1982Correspondence to Dr R. Lagier, Institut de Pathologie, 40boulevard de la Cluse, 1211 Gen6ve 4, Switzerland

and the radiological appearance of the hands andfeet. A few days before the patient died aged 84 ofacute pulmonary oedema the serum urates level wasfound to have increased to 835 ,umolIl.At 77 years examination had revealed kypho-

scoliosis with lower back pain and tenderness at thelumbar level. Lumbar radiographs showed markederosion of L2 (Fig. la, b). Neurological examinationat this time showed no abnormality. On examinationa few days before her death neither paresis, paralysis,nor tendon reflex abnormalities of the lower limbswere noted.The necropsy revealed generalised arterio-

sclerosis, acute suppurative pyelonephritis, andgouty tophi in the kidneys and in the joints of thehands and feet. The parathyroids were macroscopi-cally and histologically normal.A segment (T7-L4) of the spinal column consisting

of vertebral bodies and discs was examined. Therewas an extensive erosion on L2 containing a whitepasty material which consisted of sodium uratemonohydrate as demonstrated in 2 different samplesby x-ray diffraction. The 2 separate lateral masses ofthis eroded vertebral body were composed of remod-elled bone and fibrocartilaginous tissue. Impaction ofLi in L2 created a spinal angulation. The lower bor-der of the Li body showed fibrocartilaginous remod-elling, and the lower right angle showed histologicalsigns of tophi (Fig. 2).No osteophytes or intervertebral bony bridges

were observed elsewhere in the same specimen. Thevertebral bodies and discs appeared normal exceptfor a small tophus facing the lower vertebral plateT9 and a small cartilaginous Schmorl's node at thelevel of the lower plate of T8 (Fig. 3b). This T9tophus consisted of grouped, histologically charac-teristic microtophi; it was limited by an arcade oflamellar bone tissue (Fig. 4a). Just in front of thetophus the vertebral plate bone cortex had disap-peared and the underlying cartilaginous plate, whichwas otherwise normal, was eroded on its deep sur-face. The corresponding annulus fibrosus was normal

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Spondylodiscal erosions due to gout 351

Fig. 1 Radiographs centred on thespondylodiscal erosion of L2. (a)Lateral view ofsegment T12-L3(19 February, 1975). (b)Anteroposterior view ofsegmentLJ-L3 (19 February, 1975). (c) APview ofpost-mortem anteriorfrontal section ofsegment Ll-L3(died 6 June, 1981).

Fig. 2 Pathological aspect ofthe spondylodiscal erosion ofL2. (a) Macroscopic view of the frontal section surface fromsegment T12-L3 (celloidin-embedded block). The small white spots seen in Ll and in the remnants ofL2 are artefacts and noturate deposits. (b) Histological image ofthe eroded lower right vertebral angle, with gout microtophi on the right(Haematoxylin and eosin, x 20).

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352 Lagier, Mac Gee

Fig. 3 Anterior frontal section surface T8-TJO. (a) AP post-mortem radiograph. (b) Macroscopic view offrontal sectionsurface ( xI *4 celloidin-embedded block). Gout tophus against the lower plateau of T9 (arrow indicates the same regionas also indicated by short arrow in Fig. 4a, b). Schmorl's node at the level ofthe lower plate of T8.

Fig. 4 Histological details(haematoxylin and eosin) ofFig.3b. (a, b) Tophus against the lowerplateau T9. Bone cortex (shortarrows) as well as the deep surfaceofthe underlying cartilaginous plate(long arrows) have been eroded.The cartilaginous plate is otherwiseundamaged. (a) Ordinary light(x7), (b) polarised light (x14).(c, d) Schmorl's node opposite adisc showing signs ofchondrosis(fissuring). Interruption ofcartilaginous plate (arrows) andbone cortex in front ofwhich a nodeofremodelled fibrocartilage andbone is seen surrounded byhaemopoietic marrow. (c)Ordinary light (x 7), (d)polarised light ( x14).

(Fig. 4a, b). The Schmorl's node was represented byan islet of remodelled fibrocartilaginous and bonetissue surrounded by haemopoietic marrow, oppositea disruption in the cartilaginous plate and in thevertebral plate bone cortex; the correspondingannulus fibrosus showed fissuring (Fig. 4c, d).

Discussion

The presence of only 2 tophi (one large, the otherquite small) on this segment of spinal column isrelated to the extreme rarity of spinal lesions in sub-jects with gout. This is probably because in addition

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Spondylodiscal erosions due to gout 353

to a high serum uric acid level certain local condi-tions, still undefined, are necessary for the formationof these tophi.

Radiological data illustrate a very slow evolutionof the lesion over the years, although the exactnumber of years involved cannot be determined. Thearchitectural rearrangement in a lamellar pattern ofthe cancellous bone in contact with the T9 tophus(Fig. 4) gives evidence of this gradual developmentand also indicates, at least in the medium term, anevolution different from that observed for the ero-sion in L2.

In addition to the slow evolution of the lesion it wasnoted that clinical manifestations were relativelyslight, which is in agreement with the observations ofTkach.6 However, a case has been reported of severebone erosion in the upper cervical region with sub-luxation of the atlas vertebra.7The small T9 tophus was situated in the somato-

discal region, as also noted by Lichtenstein et al.8 Thislocation suggests that urate deposition is related tothe special vascular conditions9 which may also per-mit blood-borne bacteria to reach a vertebral body.The presence of this tophus had induced a gradual

destruction of the vertebral plate bone cortex,followed by erosion on the deep surface of the car-tilaginous plate, which otherwise appeared undam-aged and was flanked by a normal annulus fibrosus. Aprocess of this kind may be a possible preliminarystage of a severe erosion like that of L1-L2.The mechanism of this erosion, reminiscent of that

seen in somatodiscal infectious conditions, is dif-ferent from the process which characterises inter-vertebral osteochondrosis (particularly in Schmorl'snode formation), where there is evidence of discdeterioration, cartilaginous plate interruption, andintraosseous development of fibrocartilaginous tis-sue. Thus the pathogenesis of somatodiscal erosion ingout is fundamentally different from that of vertebralerosion in chondrocalcinosis, an erosion that we con-sidered to be a severe form of intervertebral osteo-chondrosis.10 In cases of gout erosion the cavity wasfilled with a mass of monosodium urate crystals,while in chondrocalcinosis erosion the cavity wasfound to contain no mass of calcium pyrophosphatedihydrate crystals.

Although it is necessary in evaluating cases of ver-

tebral erosion to note the presence of coexisting goutor hyperuricaemia, it must be borne in mind thatother conditions resulting in radiologically similarerosions are far more frequent. The differential diag-nosis must be made with regard to infectious spondy-litis rather than intervertebral osteochondrosis, inwhich the spondylodiscal lesions are usually morediffuse.When a surgical biopsy or punch biopsy is per-

formed a part of the specimen-according to the sizeand aspect of this specimen-should be fixed in abso-lute alcohol to preserve the urate crystals. X-ray dif-fraction of 'chalky' material could also be useful.Although a careful surveillance of vertebral erosionsin patients suffering from gout is obviously impor-tant, these lesions do not necessarily seem to have apoor prognosis.

The authors thank Professor C. A. Baud and Dr A. Schoenboerner,Institute of Morphology, Geneva Medical School, who did the x-raydiffraction analysis, and Mrs. M. Maunoir, who made the histologi-cal preparations.

References

1 Kawenoki-Minc E, Staniszewska-Varga J, Abgarowicz T, et al.Incidence of spondylolysis, ankylosing hyperostosis, spondylosisand sacroiliac joint changes in patients with gout (Pols.)Reumatologia 1978; 16: 499-507 (abstr in Excerpta Medica).

2 Hall M C, Selin G. Spinal involvement in gout: a case report withautopsy. J Bone Joint Surg 1960; 42A: 341-3.

3 Litvak J, Briney W. Extradural spinal depositions of uratesproducing paraplegia: case report.J Neurosurg 1973; 39: 656-8.

4 Sequeira W, Bouffard A, Salgia K, Skosey J. Quadriparesis intophaceous gout. Arthritis Rheum 1981; 24: 1428-30.

5 Wald S L, McLennan J E, Carroll R M, Segal H, Exraduralspinal involvement by gout: case report. J Neurosurg 1979; 50:236-9.

6 Tkach S. Gouty arthritis of the spine. Clin Orthop 1970; 71:81-6.

7 Kersley G D, Mandel L, JeffreyM R. Gout, an unusual case withsoftening and subluxation of the first cervical vertebra andsplenomegaly. Result of ACTH administration and eventualpost-mortem findings. Ann Rhem Dis 1950; 9: 282-304.

8 Lichtenstein L, Scott H W, Levin M H. Pathologic changes ingout: survey of eleven necropsied cases. Am J Pathol 1956; 32:871-95.

9 Crock H V, Yoshizawa H, Kame S K. Observations on thevenous drainage of the human vertebral body. J Bone Joint Surg1973; 55B: 528-33.

10 Lagier R, Mac Gee W. Erosive intervertebral osteochondrosis inassociation with generalised osteoarthritis and chondro-calcinosis, Anatomico-radiological study of a case. Z Rheumatol1979; 38: 405-14.

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