Browns Tumor - a Rare Cause of Pathological Fracture Neck of Femur: Problems in Diagnosis and Treatment Arun K.P., Wozniak A.P., Rysavy M., and Al Emadi E

QATAR MEDICAL JOURNAL VOL. 14 / NO. 21 / JUNE 2005

CASE REPORT

Browns Tumor - A Rare Cause of Pathological Fracture Neck of Femur: Problems in Diagnosis and Treatment Arun K.P., Wozniak A.P., Rysavy M., and Al Emadi E. Orthopedics Section, Department of Surgery, Hamad Medical Corporation Doha, Qatar

Abstract: The patient was admitted for a dynamic hip screw fixation. In the theater while reducing the hip by traction on the orthope- Pathological fractures in primary hyperparthyroidsm dic table, it was noticed that the fracture had occurred through a are usually seen in the late stages of the disease. It is ex- well-defined cyst in the neck of the femur which was well cir- tremely rare to see such fractures in asymptomatic hyperparathyroidsm. We present such a case and discuss cumscribed and appeared benign. Intraoperative biopsy of the the diagnostic difficulties and problems in treatment. cyst wall was done and a dynamic hip screw fixation routinely performed. Case History: The biopsy material consisted of curetting from the cyst. A 40-year-old Asian male who works as a supervisor in a The bone reamings were used to graft the cyst. The biopsy was steel factory was admitted to the hospital on 28th March 2001 reported to show marked fragmentation through a fibrocol- with a history of a fall at home. He presented with pain in the lagenous cyst and provisionally diagnosed as an aneurismal bone right hip and was unable to weight bear. There was nothing cyst. significant in his past medical history. Systemic review was non- Follow up investigations, which included routine blood contributory. On examination the patient was of frail stature. chemistry, were normal. An isotope scan to identify any other His vital signs were stable. The right leg was shortened, ad- bone lesion was negative except for increased uptake at the frac- ducted and externally rotated with severe pain on all movements. ture site. X-ray of the hip six weeks post operatively showed X-ray of the hip (Figure I) showed an intertrochanteric frac- that there was no healing of the cyst and it was decided to admit ture of the right femur. Investigations on admission revealed a the patient for repeat biopsy, curettage and grafting or cement- Normal WBC count, Hg of 12.3 g/dl normal glucose, urea and ing. On this admission also blood investigations were normal electrolytes. including his serum calcium, this was 2.33 mmol/1 (normal 2.1- 2.6 mmol/1). During surgery the lesion which had extended into the cal- car was exposed and it found to consists of a brown friable tumor mass, which macroscopically resembled a giant cell tumor. Frozen section was arranged but was not conclusive. As the macroscopic features of the cyst resembled giant cell tumor and in this age group this remained a likely diagnosis the cyst was curetted and bone cement inserted (Figure 2). The biopsy material was again reported as an aneurismal bone cyst. On the third day after this procedure the patient developed pain! s abdominal distension with watery diarrhea and vomit- ing. A plain X-ray of the abdomen was consistent with Ileus Figure 1 and it also revealed nephrocalcinosis. Subsequent investigation performed then revealed normal glucose of 8.8 mmol/1, normal BUN and electrolytes and elevated serum calcium of Address for correspondence: 2.88 mmol/1 (normal 2.1-2.6 mmol/1). Dr. K. P. Arun Orthopedics Section, Department of Surgery Review and closer scrutiny of the pelvic X-ray showed fur- Hamad Medical Corporation ther lytic areas in the iliac bones, which were initially were taken P.O. Box 3050, Doha, Qatar

46 Browns Tumor: A Rare Cause of Pathological Fracture Neck of Femur... Arun K. P., et. al.

Figure 2 Figure 3 to be gas shadows. Parathyroid hormone assay was done which were markedly elevated 594 IU (normal 9-55). An ultrasound of the thyroid gland revealed solitary parathyroid adenoma in the right lobe of the thyroid. A TCC 99 Tetrofosmin neck and mediastinal nuclear scan however was negative. A fine needle aspiration biopsy of the right lobe showed parathyroid adenoma. A diagnosis of primary hyperparathyrodism was confirmed with associated brown tumor of the neck right femur. Patient underwent a right hemithyroidectomy and the serum calcium, which was 3.13 mmol/1 returned to 2.5 mmol/1. Now with a definite diagnosis it was decided to remove the cement and to graft the defect with corticcancellous bone. The decision to do this was based on the fact that the patient was f young, the primary pathology was dealt with and subsequent a spontaneous healing of a brown tumor in the neck of femur can be expected with corticocancellous graft0 \ Figure 4 However after 6 months of follow up, X-ray revealed that sis and treatment options(1). Fracture through a brown tumor in the hip screw was penetrating the soft bone and the head of asymptomatic hyperparathyroidism is an extremely rare occur- femur showed signs of avascular necrosis (Figure 3). On 13th rence about 12%(3). X-ray of the fracture reviewed retrospec- January 2002 that is 9 months after the initial injury patient had tively did not show the lesion well and it only became apparent a total hip replacement (Figure 4). At surgery it was noticed when the fracture was reduced on the orthopedic table. Initial that there was no healing in and around the cyst. The femoral suspicion of a pathological fracture would have warranted a CT head was very soft and friable and had cystic changes. Follow- examination. ing the total hip replacement he made an uneventful recovery. He returned to work and at three year follow up he had excel- Biopsy reports of these lesions are often misleading and re- lent pain free range of movement of the hip. quire considerable histopathological expertise. Clinically, ra- diologically and histologically a Brown tumor may be are often Discussion: misdiagnosed as a giant cell tumor or aneurismal bone cyst es- Pathological fracture from benign and locally aggressive pecially in the absence of clinical or biochemical findings con- lesions in the neck of femur are a challenge in terms of diagno- sistent with hyperparathyrodism(4).

QATAR MEDICAL JOURNAL VOL. 14 / NO 1 / JUNE 2005 47 Browns Tumor: A Rare Cause of Pathological Fracture Neck of Femur. Arun K. P., et. al.

The initial choice to cement the defect cyst was made, as patients on chronic renal dialysis where if pathological fracture macroscopically the tumor resembled Giant cell tumor and fro- occurs a brown tumor has to excluded(6). In this case however zen section was not conclusive. This is a commonly used method pathological fracture was initial serum calcium and skeletal bio- of augmented fixation in weight bearing bone. Once a diagno- chemistry was normal. sis of hyperparathyroidism was made and the primary condi- A cold scan is a feature of giant cell tumor and brown tu- tion treated it was thought that the lesion would heal satisfacto- mor, where there is little or no reactive osteoblastic activity (in rily with cortcocancellous bone graft and offer better long term contrast to most skeletal metastasis). It was only during the (1) results in a younger patient . In hyperparathyroid patients one second admission when the serum calcium was elevated and (2) can expect delay in fractures healing . the nephrocalcinosis detected on the plain X-ray together with After parathyroidectomy with time bone density improves other lytic lesion retrospectively seen on the pelvic X-ray that and the rate of fracture healing returns to normal. This improves the diagnosis was suspected and further specific investigation the result of the orthopedic procedure(8). Since the adenoma was performed confirming the diagnosis of parathyroid adenoma. removed the chances of healing are improved and we therefore This case illustrates the many diagnostic difficulties encoun- elected to apply the corticocancellous graft to the lesion to lessen tered in occult parathyroid disease relating to clinical evalua- the risk of implant failure. Benign tumors in the neck of femur tion and radiological and biochemical investigations. All pa- are rare. The difficulty in clinical and radiological diagnosis tients with pathological fractures should have their serum (total were further compounded by the negative supplementary in- and ionized) estimated and if clinical or radiological features of vestigations. Cases of normocalcemic hyperparathyroidism are hyperparathyroidism is present, the parathyroid hormone esti- reported in the literature(5) but are rare. mation done(7). It also highlights the difficulties encountered in treatment of these pathological fractures in the neck of femur. Although Skeletal manifestation can occur very early in primary hyperparathyroidism as this case demonstrates, a brown A careful evaluation of the patient and a high index of sus- tumor is a rare and usually late event. It is more common in picion is required when these patients are initially evaluated.

References: 1. Eugene K. Wai, Aileen M. Davis, Anthony Griffins, Robert S. 5. Luong KV, Nguyen LT. Normocalcemic hyperparathyroidsm in Bell and Jay S. Wunder. Pathological fractures of proximal Vietnamese Immigrants living in Southern California. femur secondary to Benign Bone tumors; CORR No. 383; Am J Med Sci.; June 2000, pp 279-286, April 2001. 6. Jeren Strujic, et al. Secondary hyperparathyroidsm and brown 2. Lincourt JE, Hochberg. Delayed fracture healing in tumor in dialyzed patients. Ren-Fail; Mar 2001. Hyperparathyrodism. Clin. Ortho.; May 1977. 7. Singhal S, Johnson CA, Udelsman R. Primary hyperparathy- 3. Diamond TH, Both JR, Kalk WJ, Shires R. Primary rodism: What every Orthopedic Surgeon should know- hyperparathyroidsm - a study of 100 patients in Johannesburg. Orthopedics; Oct. 2001. S. Afr. Med. J; Jan 1986. 8. Thorsen K; Kristoffersson AO; Lorentzon RP. Changes in bone 4. Ferrari D, Baladini N, Busanelli L, Tigani D. Two cases of mass and serum markers of bone metabolism after parathy- hyperparathyrodism initially diagnosed as aneurismal cyst roidectomy. Surgery 122(5); 882-1; Nov. 1997. Chir Organi; Sept-Dec. 1996.

Note from the Editor-in-Chief

Please note that in the article entitled "Complications of Diabetes Mellitus Among Patients Attending Outpatient Clinic in Qatar" published in QMJ, Volume 12 / Number 2 / December 2003, pp 129-132, the first author should be Yousef M.F. and the second author should be Zirie M. A. An error occurred while doing the graphic on the article.