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Cystic tuberculosis of the bone mimicking osteogenic sarcoma
Tubercleand LungDisease (1996) 77, 566-568 © 1996 Pearson ProfessionalLtd
Case report Cystic tuberculosis of the bone mimicking osteogenic sarcoma K. M. H. Yip, J. Lin, R C. Leung
Department of Orthopaedics and Traumatology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong S U M M A R Y. Hong Kong has a relatively high incidence of tuberculosis in comparison with other developed cities, possibly due to the influx of mainland Chinese immigrants and Vietnamese boat people. However, primary, solitary cystic tuberculous infection of the bone is rare and few cases have been reported. Radiological appearances of this disease can mimic several bone conditions, including bone cyst, osteoblastoma and even osteosarcoma. We report on a case of a healthy fifteen-year-old who presented with swelling to the left elbow; biopsy confirmed this as cystic tuberculosis of the bone.
R/~ S U M/~. L'incidence de la tuberculose h Hong Kong est relativement plus 61ev6e que celle d ' a u t r e s villes d~velopp6es, sans doute p a r suite de l'afflux d ' i m m i g r a n t s Chinois provenant du continent et de ' b o a t people' vietnamiens. Toutefois, l'infection primaire tuberculeuse cystique et solitaire de l'os est rare et peu de cas en ont 6t6 rapport6s. L'aspect radiologique de cette maiadie peut ressembler h d'antres maladies osseuses, notamment les kystes osseux, l'osteoblastome et m6me l'ost6osarcome. Nous rapportons le cas d ' u n sujet en bon 6tat g~n6ral, ~g6 de quinze ans et consultant pour un gonflement du coude gauche; la biopsie confirme qu'il s'agit d ' u n e tuberculose osseuse kystique.
R E S U M E N . Hong Kong tiene una incidencia de tuberculosis relativamente mils alta que otras ciudades desarolladas, posiblemente debido al flujo de inmigrantes chinos provenientes del continente y de vietnamitas ('boat people'). Sin embargo, la infecci6n tuberculosa primaria, quistica y 6nica de los huesos es r a r a , habi6ndose registrado s61o algunos casos. El aspecto radiol6gico de esta enfermedad puede semejar varias afecciones 6seas incluyendo el quiste 6seo, el osteoblastoma y ann el osteosarcoma. I n f o r m a m o s sobre el caso de un sujeto sano de 15 afios de edad, quien present6 un aumento de volumen del codo izquierdo, la biopsia habiendo confirmado que se t r a t a b a de una tuberculosis quistica del hueso. size, without a history of trauma. There were no respiratory symptoms. Constitutional symptoms such as fever, weight loss and loss of appetite were also absent. Bacille Calmette-Gu6rin (BCG) vaccination had been given at infancy, according to the immunization schedule in Hong Kong. There was no obvious history to suggest that the patient was immunocompromised. On clinical examination, he was afebrile. There was a 2 cm swelling over the proximal left ulna, which was tender, hard in consistency, and appeared to be part of the underlying bone. The overlying skin appeared to be normal. Active and passive movements of the elbow were normal. However, lymphadenopathy was noticed in the axillary region of the affected limb. Systemic examination including the chest was unremarkable. The patient had a leucocytosis of 11.4 x 109/1 and a slightly raised erythrocyte sedimentation rate of 15. Bonespecific alkaline phosphatase was within the normal range. Plain radiographs of the left ann revealed an osteolytic lesion with associated periosteal elevation in the
INTRODUCTION Primary cystic tuberculous infection of the bone is rare and only a few cases have been reported. 1-3 Radiological appearances of this disease can mimic several bone conditions, including bone cyst, osteoblastoma and even osteosarcoma. Lack of awareness of this condition could lead to delays in diagnosis. We present an interesting case of cystic tuberculosis of the bone.
CASE REPORT A 15-year-old boy presented with a 2 month history of left elbow swelling, painful and gradually increasing in
Correspondence to: Dr Kevin M. H. Yip, Departmentof Orthopaedics and Tranmatology,Chinese Universityof Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. Te1:+852-26322727;Fax:+85226377889. 566
Cystic tuberculosisof the bone 567
Figure--Anterior posterior and lateraIplain radiographs of the left elbow.
metaphysis of the proximal ulna (Figure). The lesion was radiolucent, round and somewhat expanding with a variable amount of sclerosis. There was a multilocular appearance. At this point the differential diagnoses were osteoblastoma, pyogenic infection or aneurysmal bone cyst; tuberculous osteomylitis was not high on the list of differential diagnoses. Plain radiograph of the chest and CT scans of the thorax were normal. No other bony lesions were visible on the bone scan. Trephine needle biopsy of the elbow swelling revealed a mixture of lymphocytes, polymorphs and eosinophils. No malignant cells were seen. Fine needle aspiration of the axillary lymph node showed no malignant cells. Acid-fast bacilli stain on both the contents of the bone lesion and the lymph node were negative. As the trephine needle biopsy had not contributed to the diagnosis, open biopsy was then performed. After the cortex was opened, yellow watery fluid extruded from the bone marrow. This, together with a sample of the cystic wall and bony fragments, was sent for histopathological and microbiological examination. Excision and curettage to remove all granulation tissue was then performed. There was no communication between the lesion and the neighbouring joint. Histological examination showed granulation tissue infiltrated by acute and chronic inflammatory cells. Ziehl-Neelsen stain demonstrated the presence of acidfast bacilli. Mycobacterium tuberculosis bacteria were later cultured and found to be sensitive to streptomycin, pyrazinamide, isoniazid and rifampicin. Post-operatively, the patient was given a hinged long arm brace and anti-tuberculosis chemotherapy was initiated one week after the operation. One month later the brace was removed, and his elbow was completely free of pain with a full range of movement. Plain radiograph
of the left elbow confirmed that the lesion had not recurred.
DISCUSSION In this present day and age, tuberculosis is relatively uncommon in developed countries. However, Hong Kong has a higher incidence of tuberculosis than other developed cities, possibly due to the influx of mainland Chinese immigrants and Vietnamese boat people whose general standard of health is poor. Solitary cystic tuberculosis of the bone is rare; only a few cases have been described. 1~*There is a predilection for metaphysis of the long bones, probably due to the vasculature in this region. 5 Tubercle bacilli probably lodge in the small terminal branches of the arteries of the metaphysis and grow, caseate and produce a cystic lesion. They may extend to and invade through the cortex, and may also extend into the epiphysis. Sequestra are uncommon and smaller than in pyogenic infection? ,6,7 The lesions are usually solitary because sensitization of the patient to the organism occurs before the onset of systemic disease. If host response is poor, then the lesion may become multiple. Likewise, multifocal lesions are less common now than 50 years ago. Clinically most patients present with localised tenderness, swelling and limitation of movement. The most common radiological features include an area of radiolucency, and demineralisation around the affected lesion. Periosteal reaction is uncommon. Bone scan is only useful for localising other lesions; however, tuberculin tests should be performed in all cases, although most are usually positive (90%). 8 Staining is frequently falsely negative.
568 Tubercleand Lung Disease The anti-tuberculosis regimen given consisted of a combination of streptomycin, rifampicin, isoniazid and pyrazinamide. All four drugs are given once daily for the first 4 weeks; streptomycin is then omitted, with the three remaining drugs given twice weekly for the next 6 weeks. In the following 12 weeks, rifampicin and isoniazid are given twice weekly. Pyridoxine is given throughout treatment. A full course of anti-tuberculosis chemotherapy must be given. For the surgical management of these lesions, debridement and drainage are usually adequate. Bone grafting is not necessary, since most patients respond well to modem anti-tuberculosis medication. As this is a mechanically weak point, bracing may be required until radiological healing has taken place in order to prevent pathological fracture. Lesions may be asymptomatic and may only be revealed after minor trauma. This, together with lack of familiarity, may lead to misdiagnosis. For these reasons, all suspicious bone lesions should be biopsied.
Acknowledgement We would like to thank Miss Joanna Cowan for assisting in the preparation of this manuscript.
References 1. Hartofilakidis-GarofalidisG. Cystic tuberculosisof the patella: report of 3 cases. J Bone Joint Surg Am 1969: 51-A:582-585. 2. Versfeld G A, SolomonA. A diagnosticapproach to tuberculosisof bones and joints. J Bone Joint Surg Br 1982; 64-B: 446-449. 3. AbdelwahabI F, Present D A, Gould E et al. Tuberculosisof the distal metaphysis of the femur. Skeletal Radiol 1988; 17: 199-202. 4. NielsenF F, Helmig O, de CarvalhoA. Tuberculosisof calcaneus and talus with negativetuberculinskin test. Skeletal Radiol 1989; 18: 153-155. 5. Edeiken J, De PalmaA F, Moskowitz H et al. 'Cystic' tuberculosis of bone. Clin Orthop 1963; 28: 163-168. 6. KominsC. Multiplecystic tuberculosis: a review and a revised nomenclature.Br J Radiol 1952; 25: 1-8. 7. GoldblattM, CreminB J. Osteo-articulartuberculosis:its presentationin coloured races. Clin Radiol 1978; 29: 669-677. 8. Valejo J, Ong L T, Starke J R. Tuberculousosteomyelitisof the long bones in children.Pediatr Infect Dis J 1995; 14: 542-546.
Case report Cystic tuberculosis of the bone mimicking osteogenic sarcoma K. M. H. Yip, J. Lin, R C. Leung
Department of Orthopaedics and Traumatology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong S U M M A R Y. Hong Kong has a relatively high incidence of tuberculosis in comparison with other developed cities, possibly due to the influx of mainland Chinese immigrants and Vietnamese boat people. However, primary, solitary cystic tuberculous infection of the bone is rare and few cases have been reported. Radiological appearances of this disease can mimic several bone conditions, including bone cyst, osteoblastoma and even osteosarcoma. We report on a case of a healthy fifteen-year-old who presented with swelling to the left elbow; biopsy confirmed this as cystic tuberculosis of the bone.
R/~ S U M/~. L'incidence de la tuberculose h Hong Kong est relativement plus 61ev6e que celle d ' a u t r e s villes d~velopp6es, sans doute p a r suite de l'afflux d ' i m m i g r a n t s Chinois provenant du continent et de ' b o a t people' vietnamiens. Toutefois, l'infection primaire tuberculeuse cystique et solitaire de l'os est rare et peu de cas en ont 6t6 rapport6s. L'aspect radiologique de cette maiadie peut ressembler h d'antres maladies osseuses, notamment les kystes osseux, l'osteoblastome et m6me l'ost6osarcome. Nous rapportons le cas d ' u n sujet en bon 6tat g~n6ral, ~g6 de quinze ans et consultant pour un gonflement du coude gauche; la biopsie confirme qu'il s'agit d ' u n e tuberculose osseuse kystique.
R E S U M E N . Hong Kong tiene una incidencia de tuberculosis relativamente mils alta que otras ciudades desarolladas, posiblemente debido al flujo de inmigrantes chinos provenientes del continente y de vietnamitas ('boat people'). Sin embargo, la infecci6n tuberculosa primaria, quistica y 6nica de los huesos es r a r a , habi6ndose registrado s61o algunos casos. El aspecto radiol6gico de esta enfermedad puede semejar varias afecciones 6seas incluyendo el quiste 6seo, el osteoblastoma y ann el osteosarcoma. I n f o r m a m o s sobre el caso de un sujeto sano de 15 afios de edad, quien present6 un aumento de volumen del codo izquierdo, la biopsia habiendo confirmado que se t r a t a b a de una tuberculosis quistica del hueso. size, without a history of trauma. There were no respiratory symptoms. Constitutional symptoms such as fever, weight loss and loss of appetite were also absent. Bacille Calmette-Gu6rin (BCG) vaccination had been given at infancy, according to the immunization schedule in Hong Kong. There was no obvious history to suggest that the patient was immunocompromised. On clinical examination, he was afebrile. There was a 2 cm swelling over the proximal left ulna, which was tender, hard in consistency, and appeared to be part of the underlying bone. The overlying skin appeared to be normal. Active and passive movements of the elbow were normal. However, lymphadenopathy was noticed in the axillary region of the affected limb. Systemic examination including the chest was unremarkable. The patient had a leucocytosis of 11.4 x 109/1 and a slightly raised erythrocyte sedimentation rate of 15. Bonespecific alkaline phosphatase was within the normal range. Plain radiographs of the left ann revealed an osteolytic lesion with associated periosteal elevation in the
INTRODUCTION Primary cystic tuberculous infection of the bone is rare and only a few cases have been reported. 1-3 Radiological appearances of this disease can mimic several bone conditions, including bone cyst, osteoblastoma and even osteosarcoma. Lack of awareness of this condition could lead to delays in diagnosis. We present an interesting case of cystic tuberculosis of the bone.
CASE REPORT A 15-year-old boy presented with a 2 month history of left elbow swelling, painful and gradually increasing in
Correspondence to: Dr Kevin M. H. Yip, Departmentof Orthopaedics and Tranmatology,Chinese Universityof Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. Te1:+852-26322727;Fax:+85226377889. 566
Cystic tuberculosisof the bone 567
Figure--Anterior posterior and lateraIplain radiographs of the left elbow.
metaphysis of the proximal ulna (Figure). The lesion was radiolucent, round and somewhat expanding with a variable amount of sclerosis. There was a multilocular appearance. At this point the differential diagnoses were osteoblastoma, pyogenic infection or aneurysmal bone cyst; tuberculous osteomylitis was not high on the list of differential diagnoses. Plain radiograph of the chest and CT scans of the thorax were normal. No other bony lesions were visible on the bone scan. Trephine needle biopsy of the elbow swelling revealed a mixture of lymphocytes, polymorphs and eosinophils. No malignant cells were seen. Fine needle aspiration of the axillary lymph node showed no malignant cells. Acid-fast bacilli stain on both the contents of the bone lesion and the lymph node were negative. As the trephine needle biopsy had not contributed to the diagnosis, open biopsy was then performed. After the cortex was opened, yellow watery fluid extruded from the bone marrow. This, together with a sample of the cystic wall and bony fragments, was sent for histopathological and microbiological examination. Excision and curettage to remove all granulation tissue was then performed. There was no communication between the lesion and the neighbouring joint. Histological examination showed granulation tissue infiltrated by acute and chronic inflammatory cells. Ziehl-Neelsen stain demonstrated the presence of acidfast bacilli. Mycobacterium tuberculosis bacteria were later cultured and found to be sensitive to streptomycin, pyrazinamide, isoniazid and rifampicin. Post-operatively, the patient was given a hinged long arm brace and anti-tuberculosis chemotherapy was initiated one week after the operation. One month later the brace was removed, and his elbow was completely free of pain with a full range of movement. Plain radiograph
of the left elbow confirmed that the lesion had not recurred.
DISCUSSION In this present day and age, tuberculosis is relatively uncommon in developed countries. However, Hong Kong has a higher incidence of tuberculosis than other developed cities, possibly due to the influx of mainland Chinese immigrants and Vietnamese boat people whose general standard of health is poor. Solitary cystic tuberculosis of the bone is rare; only a few cases have been described. 1~*There is a predilection for metaphysis of the long bones, probably due to the vasculature in this region. 5 Tubercle bacilli probably lodge in the small terminal branches of the arteries of the metaphysis and grow, caseate and produce a cystic lesion. They may extend to and invade through the cortex, and may also extend into the epiphysis. Sequestra are uncommon and smaller than in pyogenic infection? ,6,7 The lesions are usually solitary because sensitization of the patient to the organism occurs before the onset of systemic disease. If host response is poor, then the lesion may become multiple. Likewise, multifocal lesions are less common now than 50 years ago. Clinically most patients present with localised tenderness, swelling and limitation of movement. The most common radiological features include an area of radiolucency, and demineralisation around the affected lesion. Periosteal reaction is uncommon. Bone scan is only useful for localising other lesions; however, tuberculin tests should be performed in all cases, although most are usually positive (90%). 8 Staining is frequently falsely negative.
568 Tubercleand Lung Disease The anti-tuberculosis regimen given consisted of a combination of streptomycin, rifampicin, isoniazid and pyrazinamide. All four drugs are given once daily for the first 4 weeks; streptomycin is then omitted, with the three remaining drugs given twice weekly for the next 6 weeks. In the following 12 weeks, rifampicin and isoniazid are given twice weekly. Pyridoxine is given throughout treatment. A full course of anti-tuberculosis chemotherapy must be given. For the surgical management of these lesions, debridement and drainage are usually adequate. Bone grafting is not necessary, since most patients respond well to modem anti-tuberculosis medication. As this is a mechanically weak point, bracing may be required until radiological healing has taken place in order to prevent pathological fracture. Lesions may be asymptomatic and may only be revealed after minor trauma. This, together with lack of familiarity, may lead to misdiagnosis. For these reasons, all suspicious bone lesions should be biopsied.
Acknowledgement We would like to thank Miss Joanna Cowan for assisting in the preparation of this manuscript.
References 1. Hartofilakidis-GarofalidisG. Cystic tuberculosisof the patella: report of 3 cases. J Bone Joint Surg Am 1969: 51-A:582-585. 2. Versfeld G A, SolomonA. A diagnosticapproach to tuberculosisof bones and joints. J Bone Joint Surg Br 1982; 64-B: 446-449. 3. AbdelwahabI F, Present D A, Gould E et al. Tuberculosisof the distal metaphysis of the femur. Skeletal Radiol 1988; 17: 199-202. 4. NielsenF F, Helmig O, de CarvalhoA. Tuberculosisof calcaneus and talus with negativetuberculinskin test. Skeletal Radiol 1989; 18: 153-155. 5. Edeiken J, De PalmaA F, Moskowitz H et al. 'Cystic' tuberculosis of bone. Clin Orthop 1963; 28: 163-168. 6. KominsC. Multiplecystic tuberculosis: a review and a revised nomenclature.Br J Radiol 1952; 25: 1-8. 7. GoldblattM, CreminB J. Osteo-articulartuberculosis:its presentationin coloured races. Clin Radiol 1978; 29: 669-677. 8. Valejo J, Ong L T, Starke J R. Tuberculousosteomyelitisof the long bones in children.Pediatr Infect Dis J 1995; 14: 542-546.