Cauda equina compression revealing brown tumor of the spine in a long-term hemodialysis patient

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Case report

Cauda equina compression revealing brown

tumor of the spine in a long-term hemodialysis patient

Faissal Tarrass

^*

, Amal Ayad, Meryem Benjelloun, Abdelkabir Anabi, Benyounes Ramdani, Mohamed Gharbi Benghanem, Driss Zaid

Department of Nephrology and Dialysis, Ibn Rochd University Hospital Center, 20100 Casablanca, Morocco Received 22 April 2005; accepted 9 January 2006

Available online 24 March 2006

Abstract

Brown tumors, or osteoclastomas, are erosive bony lesions arising as a complication of hyperparathyroidism (HPT). In patients with end-stage renal disease (ESRD), brown tumors are classic skeletal manifestations usually seen in severe forms of secondary HPT. However, involvement of the spine is considered extremely rare. We report a long-term hemodialysis case, in which cauda equina compression developed due to a sacral brown tumor. A decompressive surgery and subtotal parathyroidectomy were indicated to preserve neurologic function, and to ensure reminer- alization of the lesion. This case illustrates that, though rare, brown tumors should be considered in uremic patients with neurological symptoms.

Emergent decompressive surgery is required to remove pressure on neurological structures and to stabilize the spine.

Keywords:Brown tumors; Secondary hyperparathyroidism; Renal osteodystrophy; Cauda equina compression; End-stage renal disease

1. Introduction

Brown tumors, a non-neoplastic process, are known to oc- cur only in the setting of hyperparathyroidism (HPT)

[1]. In

patients with chronic renal failure, secondary HPT, which re- sults from phosphate retention and impaired calcitriol [1,25-di- hydroxyvitamin D

3

] synthesis can cause brown tumors, which appear as cysts in bone, occurring most often in the pelvis, ribs, and the mandible

[2]. Involvement of the vertebral column is

rare, and only eight cases of symptomatic brown tumors—

involving, more specifically, the cervical or thoracic spine—

have been reported in patients with secondary HPT

[1,3–9].

We report here the first case of lumbosacral involvement in a long-term hemodialysis patient, with acute cauda equina com- pression caused by a brown tumor in S1. A surgical decom- pression was needed on an emergency basis to preserve neuro- logical function.

2. Case report

A 42-year-old man on long-term hemodialysis for 10 years secondary to chronic glomerulonephritis, presented with a 2- month history of persistent pain in the middle of his lower back, his left buttock, and his left posterior thigh and leg, espe- cially on walking. The findings on physical examination re- vealed weakness of the left foot flexors and absence of the left ankle reflex, with a positive bilateral Lasègue sign and positive L’hermitte sign. Sphincter tone and sensation were normal. In- vestigations showed elevated alkaline phosphatase 1879 IU/l (70–300), grossly elevated parathyroid hormone (PTH) 1456 pg/ml (10–65), calcium 95 mg/l (85–105), phosphate 41 mg/l (25–42), and aluminum 15

μg/l (acceptable le-

vel < 30

μg/l). Plain X-rays of lumbosacral region showed a

lytic, demineralized tumor of the sacrum. Computerized tomo- graphy scanning of the lumbosacral region demonstrated a cys- tic lesion with posterior scalloping of S1 vertebra which was responsible for the caudal sac compression (Fig. 1). L5 to S3 wide decompressive laminectomy was performed and a cystic lesion was found. The thecal sac, which ended proximally, was not involved by the lesion, which clearly compressed the other sacral nerve roots. The cyst wall was opened and removed after

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Joint Bone Spine 73 (2006) 748–750

*Corresponding author. Tel.: +212 66 14 9494.

E-mail address:faissal76@hotmail.com(F. Tarrass).

doi:10.1016/j.jbspin.2006.01.011

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dissection of sacral nerve roots. Finally, the dural sheet was reconstructed. Histologic examination of the tumor revealed a granulation tissue with fibroblasts, histiocytic cells, and a few plasma cells and lymphocytes. Numerous osteoclastic giant cells and osteoid-rich bone fragments were present, with mi- crofoci of hemosiderin deposition. As the patient had second- ary HPT, we diagnosed a brown tumor. Patient improved post- operatively, and at the time of discharge had no perineural pain. Subsequently, subtotal parathyroidectomy was performed and revealed hyperplasia of the parathyroid glands. Serum PTH values fell to the lower end of the normal range. High-dose calcium was required to maintain the serum calcium levels within the normal range.

3. Discussion

Patients with end-stage renal disease (ESRD) show various changes in their bones and joints

[2,10]. Brown tumor is an

extreme form of osteitis fibrosa cystica, which in turn is a man- ifestation of renal osteodystrophy. The term renal osteodystro- phy is used to define the skeletal complications of ESRD

which are in essence a disorder of bone remodeling. The major pathogenetic mechanism leading to secondary HPT is defi- ciency of 1,25-dihydroxycholecalciferol (1,25-dihydroxyvita- min D

3

) with resulting hypocalcemia and phosphate retention, leading to increase in PTH production and secretion from the parathyroid glands

[2].

Brown tumors have been found in 1.5–13% of patients with renal failure

[11,12]. The main sites of involvement are the

mandible, maxillary sinus, sternum, pelvis, ribs, and femur

[2,11]. Involvement of the spine is less common but can re-

quire emergent surgery to preserve neurologic function and to stabilize the spine. In a review of the literature we found that nine symptomatic brown tumors involving the spine have been reported in patients with secondary HPT

[1,3–9]. All the pa-

tients were women, and six out of eight were younger than 40 years of age. The cervical spine was involved in two pa- tients

[4,6]. Four of the eight patients presented with acute neu-

rologic compromise that resolved fully after decompressive surgery.

Table 1

summarizes the main features and treatments in the previously reported cases.

When brown tumors involve the spinal column, they can cause either slowly progressive symptoms due to mass effect or acute spinal cord compression due to pathological fractures

[1,9]. Surgical treatment requires resection of the tumor that

causes neurological compression. Reconstructive surgery in which bone grafting and instrumentation are used is necessary if spinal instability is present. Spinal reconstruction in these patients is potentially more difficult because of the severe os- teoporosis and impaired bone healing

[1,2]. The use of instru-

mentation and structural bone grafts provides immediate stabi- lity during the prolonged healing process. In addition, concurrent medical or surgical treatment of the secondary HPT is essential to promote bone fusion

[1,9]. The goals of

prevention and treatment of brown tumors in patients with ESRD include normalizing blood levels of calcium and phos- phate to reverse skeletal abnormalities and prevent extraskele- tal deposition of calcium and phosphate

[1,2,9]. If medical

Fig. 1. CT scanning shows cystic lesion at S1, with posterior scalloping of the vertebra.

Table 1

Reported cases of brown tumors involving the spine in hemodialysis patients

Author Year Age

(years)

Gender Hemodialysis duration Spinal segment involved

Symptoms Treatment

Ericsson et al.[6] 1978 47 F CRF prepared for

hemodialysis

Cervical Paresis, right upper limb Tumor resection, bone graft, parathyroidectomy Bohlman et al.[5] 1986 69 F CRF not dialyzed Thoracic Back pain, paraplegia Corticosteroids, tumor

resection

Pumar et al.[8] 1990 24 F CRF not dialyzed Thoracic Incipient paraplegia Tumor resection

Barlow and Archer[4] 1993 31 F After renal transplant rejection

Cervical Neck pain,

cervicobrachial neuralgia

Minerva jacket, parathyroidectomy

Fineman et al.[1] 1999 37 F 10 years Thoracic Incipient paraplegia Tumor resection,

parathyroidectomy

Azria et al.[3] 2000 40 F After a failed renal

transplant

Thoracic Back pain Parathyroidectomy

Masutani et al.[7] 2001 39 F 11 years Thoracic Paraplegia Tumor resection,

parathyroidectomy

Vandenbussche et al.[9] 2004 34 F 2 years Thoracic Compression with

pyramidal tract findings

Decompression, posterior fusion, parathyroidectomy

Current case 2005 42 M 10 years Sacral Cauda equina

compression

Tumor resection, parathyroidectomy CRF = chronic renal failure, F = female, M = male.

F. Tarrass et al. / Joint Bone Spine 73 (2006) 748–750 749

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therapy fails to halt the progression of brown tumors, a subtotal or total parathyroidectomy is generally performed to reduce the serum levels of PTH

[1,2].

We conclude that although uncommon, brown tumors should be considered in ESRD patients, with secondary HPT and new onset of neurological symptoms. An emergent decom- pressive surgery may be needed to preserve neurologic func- tion and to stabilize the spine.

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