Nephrol Dial Transplant (1996) 11: 1870-1873
Nephrology
Dialysis
Transplantation
Teaching Point
The dialysis patient with cystic bone defects and spinal cord symptoms
G. Mourad 1 - 3 , G. Deschodt 14 , C. Turc-Baron 13 , M. Kharrat 13 , F. Segnarbieux2-3, D. Blin1-4 and
A. Argiles1-3
Departments of 'Nephrology and 2Neurosurgery, University Hospitals of 3Montpellier and 4Nimes, Montpellier, France
Introduction
A 46-year-old man was referred on July 1995 for left
cruralgia and vertebral bone cysts on CT scan. He
presented in 1960 with corticodependent and subsequently corticoresistant nephrotic syndrome due to
focal and segmental glomerulosclerosis. The patient
received multiple courses of methylprednisolone and
chlorambucil. In 1983 renal failure was diagnosed and
he needed renal replacement therapy in April 1987.
His dialysis schedule consisted of 3 x 4 h/week with a
cuprophane dialyser and 1.75 mM Ca bicarbonate
dialysate.
The patient received a cadaver kidney transplant on
March 1989. Nephrotic syndrome recurred immediately after transplantation (13 g/day of urinary protein
excretion). The graft functioned satisfactorily (serum
creatinine 130umol/l) during 4 months. Unfortunately, renal function subsequently deteriorated
and dialysis was restarted on October 1989. The new
dialysis schedule included a 4-h treatment with a
polysulphone dialyser thrice weekly with identical
bicarbonate dialysate. The patient did well and worked
full time from 1990 to 1995. During the followup period in dialysis, despite treatment including
phosphate binders and vitamin D3 derivatives, he
developed overt hyperparathyroidism, manifested by
hyperphosphataemia (2-2.5 mmol/1), hypercalcaemia
(2.6-2.8 mmol/1) and increased iPTH serum levels
(400-500 pg/ml) (normal range 10-55 pg/ml).
In early 1995, the patient complained of back pain
which gradually worsened, and cruralgia appeared
in May 1995. He was treated with non-steroidal
anti-inflammatory drugs, and subsequently low-dose
steroids were introduced (prednisolone 20 mg/day)
because of intense pain resulting in anxiety and insomnia. Biochemical parameters suggested hyperparathyroidism: serum total Ca 2.42 mmol/1, phosphate
2.3 mmol/1, alkaline phosphatase 205IU/1 (normal
range 38-126) and intact PTH 736 pg/ml. Bone X-rays
showed the presence of cystic lesions in right femoral
neck, left humeral head, and fourth lumbar vertebra.
There were no signs of subperiostal or endosteal resorption. Spine CT scan and MRI showed multiple lytic
lesions, expanding into the medullary canal and involving dorsal as well as lumbar vertebrae (Figures 1, 2).
The vertebral body as well as posterior arch were
involved (Fig. 3). The radiologists and neurosurgeons
of our institution interpreted such lesions as very
suggestive of malignancy, and less likely of amyloid
deposition. Biological data were the following: WBC
9300 cells/mm3 with normal differential, haemoglobin
7 g/dl; sedimentation rate 10/27 mm (first and second
Correspondence and offprint requests to: G. Mourad MD. Dept of
Xephrology. Hopital Lapeyronie. 371. Av Doyen G Giraud. 34295 Fig. 1. MRI of the lumbar spine: lacunar as well as solid (4th
lumbar level) lesions are seen in all the vertebrae (L2. L3. L5. SI).
Montpellier Cedex 5. France.
1996 European Renal Association-European Dialysis and Transplant Association
Cystic bone defects and spinal cord symptoms
1871
Fig. 2. MRI of the dorsal spine: the same lesions as Figure 1 are observed, particularly a large multigeodic lesion in the 10th dorsal vertebra.
Fig. 3. CT scan of the lumbar spine: the tumoral process involves the vertebral body (1) as well as posterior arch (2). The lesion expands
into the medullary canal.
1872
G. Mourad el at.
Fig. 4. CT scan of the lumbar spine, taken 3 months after parathyroidectomy. Refilling of the geodic lesion by a calcic material is observed.
hour); fibrin 2.3 g/1; C reactive protein 5 mg/1 (N< 10).
/?2-microglobulin was 35 mg/1. Electrophoresis of
serum proteins was normal. To differentiate between
hyperparathyroidism. malignancy, and bone amyloid
deposition, an iliac bone biopsy, in addition to a biopsy
of the posterior elements of the first and second lumbar
vertebrae was performed. Iliac bone biopsy showed
fibrous osteitis, osteoclastosis. and accelerated bone
remodelling, suggestive of hyperparathyroidism. Spine
biopsy showed proliferation of 'giant multinucleated
and fibroblastic fusiform cells, eroded bone trabeculae
and hypervascularization' very suggestive of brown
tumours. There were no malignant cells nor amyloid
deposits. The patient underwent total parathyroidectomy; histological examination of the removed glands
showed diffuse hyperparathyroid cell hyperplasia.
Three months after surgery cruralgia resumed and the
patient was doing well. He was treated with alfacalcidol
(1 ug x 3times/week) and CaCO3 (4g/day). Biological
data were: total serum Ca 2.45 mM; PO4 1.44 mM;
alkaline phosphatase 107IU/1, and iPTH<lpg/ml.
CT scan and MRI showed no progression of the
tumours with refilling of the geodic lesions by calcic
material (Figure 4).
Comment
Despite remarkable improvement in the prevention of
renal osteodystrophy, hyperparathyroidism remains a
frequent complication in long-term dialysis patients.
The typical presentation is biochemical abnormalities
associated with diffuse demineralization, subperiosteal
and endosteal resorption of distal clavicles and phal-
anges on bone X-rays. Brown tumours are uncommon
[ 1 ]. In our case the patient had significant biochemical
evidence of hyperparathyroidism associated with femoral, humeral and multiple vertebral cystic lesions. The
differential diagnosis was malignancy, /?2-microglobulin amyloidosis with bone cysts, and hyperparathyroidism with brown tumours.
Malignancy, and particularly lymphoma or multiple
myeloma was suggested because of nervous compression, involvement of numerous vertebrae and intrusion
of the expanding tumours in the medullary canal. In
addition our patient had received immunosuppressive
drugs before transplantation (chlorambucil) and
during transplantation (antilymphocyte globulins and
cyclosporin). However, the patient was in good shape
and had no biochemical evidence suggesting inflammation or myeloma.
The possibility of /?2-microglobulin amyloidosis with
bone cysts was entertained because of the localization
of the bone lesions (femoral head, humerus and vertebrae), the aspect of lytic lesions with little reactive bone
formation, and the long duration of renal failure [2].
Arguments against this possibility were the fact that
our patient was young, had less than 10 years of
dialysis treatment, and never experienced carpal-tunnel
syndrome. Further, in /?2-microglobulin amyloidosis,
spine involvement frequently begins in cervical vertebrae [3], whereas in our patient, lesions were localized
at the lumbar and dorsal levels, and no lesion was
observed in cervical spine.
Brown tumours are a well-recognised manifestation
of severe hyperparathyroidism. They are observed in
less than 1.5% of cases of secondary hyperparathyroidism [4] and are usually located in mandibles, ribs,
Cystic bone defects and spinal cord symptoms
pelvis, central medullary shaft of long bones and
rarely in vertebrae [5]. While spinal-cord compression
by brown tumours has been reported in primary
hyperparathyroidism [6], a single case has been
reported by Bohlman et al. in secondary hyperparathyroidism [5]. In these cases, brown tumour was
generally unique and only one case report of multiple
brown tumours in the same patient has been reported
[7]. The interest of our case resides in the fact that it
represents the confirmation of two very special clinical
features: neurological symptoms and multiple brown
tumours.
Teaching point
Think of brown tumours in the dialysis patient with
severe hyperparathyroidism; they can be found
everywhere!
1873
References
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