Skeletal Radiol (1990) 19:461M64
Skeletal Radiology
Case report 629 R. De Cristofaro, M.D. t, p. Ruggieri, M.D. 1, R. Biagini, M.D. t and P. Picci, M.D. 2 1 Ist Orthopaedic Clinic, University of Bologna, Istituto Ortopedico Rizzoli, Italy 2 Bone Tumor Center, Istituto Ortopedico Rizzoli, Bologna, Italy
Clinical information
Radiological studies
This 37-year-old m a n was admitted to o u r Institute for pain in the right hip which h a d a p p e a r e d 1 m o n t h before. Except for slight pain when the hip joint was r o t a t e d at its m a x i m u m , on physical examination no other abnormalities were noted. S t a n d a r d r o e n t e g e n o g r a m s showed a h o n e y c o m b - l i k e multilocular osteolytic area, involving the proximal end o f the femur and a c e t a b u l u m and extending t h r o u g h the cortex (Fig. 1 A, B). A C T scan revealed involvem e n t o f the hip joint a n d the presence o f a cystic mass in the soft tissues (Fig. 2 A , B). A biopsy was p e r f o r m e d and a frozen section obtained.
Fig. 1. Anteroposterior (A) and lateral (B) views of the right hip show a multilocular, "honeycomb" osteolytic area involving the proximal portion of the femur and the acetabulum Fig. 2. A CT scan confirms the articular involvement (A) and reveals a cystic mass (B) in the soft tissues, suggesting an enlarged iliopsoas bursa
Address reprint request to: Piero Picci,
M.D., Bone Tumor Center, Istituto Ortopedico Rizzoli, Via Barbiano no 1, 1-40136 Bologna, Italy 9 1990 International Skeletal Society
462
Diagnosis: Osseous hydatidosis Histologically scolices were very rarely present, but material from the cyst wall permeated the spongiosa, causing proliferation of reactive tissue with lymphocytes, eosinophils, and multinucleated giant cells (Fig. 3).
R. de Cristofaro et al. : Case report 629 The differential diagnosis included pigmented villonodular synovitis (PVS) and osteoarticular tubercolosis (TBC). In order to eradicate the lesion with a wide surgical margin an extraarticular periacetabular resection or a hemipelvectomy was considered necessary. Thus, it was elected to use
Pathological features and additional radiological studies
Fig. 3. The biopsy shows fragments of the wall of a cyst, surrounded by reactive tissue. Around the wall of the cyst, reactive giant cells are evident (H & E stain, 200 x original magnification) Fig. 4. Large geodes of the hip in a case of PVS Fig. 5. Typical radiographic features of TBC of the hip. The presence of alterations of the articular cartilage and juxta-articular osteoporosis are signs which distinguish TBC from osseous echinococcosis
medical treatment with mebendazole. At a 2-year follow-up the patient is still in treatment with a stable clinicoradiographic result.
Discussion Hydatidosis represents the most c o m m o n human disease derived from helminth, but skeletal involvement is uncommon (0.5%-4%) [1-3, 7]. In man the infection is caused by the larva of Echinococcus granulosus or, more rarely, Echinococcus alveolaris [1, 3, 7, 14]. This parasite develops its adult cycle in the bowel of a dog and its ova are voided with the feces; man generally is infected by ingesting contaminated vegetables or water. In the human bowel, the envelope of Echinococcus ova is dissolved, releasing a larval tapeworm that reaches the portal venous system and the liver, which is the most common site of infection. On occasion, the larvae pass the first barrier and reach the pulmonary capillaries. Rarely, because of the small diameter of the pulmonary capillaries, the larvae manage to pass this filter, reaching the systemic blood circulation. Thus, bone localization is unusual. In bone, hydatidosis differs from the typical unilocular cyst usually found in extra-osseous sites. Due to the resistance o f the bony tissue, the parasite develops in multiple minute cysts lacking the intense connective tissue reaction which is present in viscera. Within the cancellous bone, where it usually is located, the parasite shows slow growth, forming new vesicles as it extends in affected bone. With time the parasite may destroy the cortex and invade the soft tissues and/or the joint cartilage. The parasite is mostly found in adults, although the initial infestation may occur during childhood. The slow evolution of the disease explains the usually late onset of symptoms. The spine, pelvis, and long bones are the most common sites of involvement [3, 4, 7, 8, 14] ; generally the disease is monostotic but frequently, after destroying the cortex, the parasite invades adjacent skeletal sites.
R. de Cristofaro et al. : Case report 629 Characteristic is the almost total lack of host-tissue reaction: periosteal new bone is usually lacking and reactive hyperostosis is present only in advanced stages. Pathological fractures are important complications and represent an unfavorable prognostic factor, due to the frequent non-union that develops [12]. In the present case the clinicoradiographic differential diagnosis included pigmented villonodular synovitis (PVS). In the hip three different types of PVS are seen [10]: a pseudocoxarthritic form, characterized by articular rim shrinkage, subchondral sclerosis, osteophytosis, and some geodes; a pseudocoxitic form with an impressive reduction of the articular rim, erosions, and geodes in the femoral head and acetabulum; and the third and most frequent form characterized by large geodes located in the femoral neck and more rarely in the femoral head and acetabulum (Fig. 4). In the initial stage the geodes are usually of small dimension and the differential diagnosis with hydatidosis is difficult, because the radiographic aspects and the slow evolution are similar in both lesions. The differential diagnosis is based on the evidence of a sclerosing rim that in PVS delimits the geodes and in hydatidosis only appears in a later phase. A more c o m m o n differential diagnostic possibility includes osteoarticular TBC (Fig. 5). The presence of periosteal reaction, alterations of the joint cartilage and juxta-articular osteoporosis, typical of TBC (in which pathological fractures generally do not occur) represent useful criteria for the diagnosis [3]. Infrequently, especially in the pelvis, diagnosis of chondrosarcoma may be considered. This diagnosis may be suspected when a large destructive lesion invading the soft tissues, with calcification and/or ossification, is present. Chondrosarcoma usually may be excluded because of its very slow evolution and the formation of a sclerotic bony reaction in advanced stages. In long bones the differential diagnosis with fibrous dysplasia or, more rarely, with giant cell tumor sometimes arises. However, in hydatidosis interruption of the cortex with
463 a large mass in the soft tissues and, with epiphyseal lesions, articular involvement with invasion of the adjacent bony segments is frequent. Moreover, in fibrous dysplasia, a "frosted glass" appearance, a sign of primitive or woven bone, is often present. In giant cell tumor, especially in its less aggressive forms, pseudosepta in this osteolytic lesion are evident. Laboratory studies (e.g., Casoni's intradermal test, complement fixation test, haemagglutination test, and eosinophil count) are very useful in establishing the diagnosis. However, false positive and false negative results occur [5]. The usual medical history must lead to a diagnostic suspicion. The presence of an osteolytic lesion similar to hydatidosis in a patient coming from a region where the disease is endemic or working in contact with dogs (the principle source of contamination for man), mandates serious consideration of the diagnosis of hydatid disease. Several medical and surgical therapeutic possibilities exist. Numerous drugs are available (e.g., thymol [5], tartar emetic [5], emetin [5], mebendazole [8]) and different types of surgery are performed according to the site, the extent o f the lesion, and the presence of a pathological fracture. Some authors [2] state that a simple curettage is sufficient therapy, whereas others [1, 8, 9] recommend a more aggressive surgical approach (en bloc resection or amputation), the latter believing that such a treatment is necessary when a pathological fracture occurs and/or the adjacent soft tissues are contaminated [6]. Considering the role of immune factors in the pathogenesis of the disease, treatment by desensitization with hydatid antigen in association with surgery has been tried [4]. This treatment is used in skeletal lesions, but has proved particularly efficient in visceral involvement. During surgery it is mandatory to avoid rupture of the fragile membrane surrounding the cysts with consequent leakage of daughter cysts, leading to unavoidable recurrence. A possible solution consists in flushing the cyst cavity with scoleci-
dal solutions such as formaldehyde [2, 9], ethacridina lactate [6], supersaturated sodium chloride [6, 9], silver nitrate [11, 13], or hydrogen peroxide [5, 9], or by freezing the external wall of the cyst before removal to make it more resistant [13]. In summary, hydatidosis is a common infection that infrequently involves the skeleton. When this happens the prognosis is uncertain because of the possible extension of the disease and serious complications, (e.g., pathological fractures, visceral involvement, neurologic damage from vertebral involvement). For this reason, simple curettage is not sufficient for cure and no medical treatment can surely eradicate the disease. Hydatidosis, in our opinion, should be staged and surgically treated like a malignant tumor (e.g., with wide surgical margins). Medical treatment is useful in association with surgery and remains the only therapy for inoperable lesions. A case of echinococcosis of the hip joint in a 37-year-old man has been reported. In this case the clinicoradiographical features suggested pigmented villonodular synovitis. P r o o f was obtained on the basis of a frozen section on biopsy. The clinical and laboratory characteristics o f hydatidosis were discussed, with emphasis on the medical and surgical treatment of the disorder. Acknowledgement. Supported in part by the Italian National Council of Research, special project "Oncology", grant no. 87.02810.44 and Research Fund of Istituto Ortopedico Rizzoli. References
1. Alldred AJ, Nisbet NW (1964) Hydatid disease of bone in Australasia. J Bone Joint Surg 46 B :260 2. Booz MK (1972) The management of hydatid disease of bone and joint. J Bone Joint Surg 54B:698 3. Da Rin F, Ghirardini GL (1982) Echinococcosi ossea. Rapporto diagnostico con la Tubercolosi osteo-articolare. Atti SERTOT 24:103 4. Duran H, Ferrandez L, Gomez-Castresana F, Lopez-Duran L, Mata P, Brandau D, Sanchez-Barba A (1978) Osseous hydatidosis. J Bone Joint Surg 60A:685 5. Hammouda NA (1974) Hydatid disease of man: a review. Egypt Orth J 9 : 279 6. Hopper J, McLean I (1977) Hydatid dis-
464 ease of the femur. J Bone Joint Surg 59A: 974 7. Jaffe HL (1972) Metabolic, degenerative, and inflammatory diseases of bones and joints. Lea & Febiger, Philadelphia 8. Maggi G (1986) La resezione chirurgica radicale nel trattamento della echinococcosi ossea degli artie del bacino. Chir Org Mov LXXI:33 9. Mnyameh W, Yacoubian V, Bikhazi K
R. de Cristofaro et al. : Case report 629 (1977) Hydatidosis of the pelvis girdle treatment by partial pelvectomy. J Bone Joint Surg 59A: 538 10. Moroni A, Innao V, Picci P (1983) La sinovite villonodulare pigmentosa dell'anca. Giorn It Ortop Traum 9: 347 11. Najarian I, Saidi F (1971) Silver nitrate as a scolecide in the treatment of Echinococcosis of man. Tropenmed Parasitol 2:188 -
12. Puxeddu L (1975) La fratture patologiche nell'echinococcosi ossea. Giorn It Ortop Traum [Suppl] 1 : 183 13. Saidi F, Najarian I (1971) Surgical treatment of hydatid cysts by freezing the cyst wall and installation of 0.5% silver nitrate. New Engl J Med 24:1346 14. Wilner D (1982) Radiology of bone tumors and allied disorders. WB Saunders, Philadelphia
Skeletal Radiology
Case report 629 R. De Cristofaro, M.D. t, p. Ruggieri, M.D. 1, R. Biagini, M.D. t and P. Picci, M.D. 2 1 Ist Orthopaedic Clinic, University of Bologna, Istituto Ortopedico Rizzoli, Italy 2 Bone Tumor Center, Istituto Ortopedico Rizzoli, Bologna, Italy
Clinical information
Radiological studies
This 37-year-old m a n was admitted to o u r Institute for pain in the right hip which h a d a p p e a r e d 1 m o n t h before. Except for slight pain when the hip joint was r o t a t e d at its m a x i m u m , on physical examination no other abnormalities were noted. S t a n d a r d r o e n t e g e n o g r a m s showed a h o n e y c o m b - l i k e multilocular osteolytic area, involving the proximal end o f the femur and a c e t a b u l u m and extending t h r o u g h the cortex (Fig. 1 A, B). A C T scan revealed involvem e n t o f the hip joint a n d the presence o f a cystic mass in the soft tissues (Fig. 2 A , B). A biopsy was p e r f o r m e d and a frozen section obtained.
Fig. 1. Anteroposterior (A) and lateral (B) views of the right hip show a multilocular, "honeycomb" osteolytic area involving the proximal portion of the femur and the acetabulum Fig. 2. A CT scan confirms the articular involvement (A) and reveals a cystic mass (B) in the soft tissues, suggesting an enlarged iliopsoas bursa
Address reprint request to: Piero Picci,
M.D., Bone Tumor Center, Istituto Ortopedico Rizzoli, Via Barbiano no 1, 1-40136 Bologna, Italy 9 1990 International Skeletal Society
462
Diagnosis: Osseous hydatidosis Histologically scolices were very rarely present, but material from the cyst wall permeated the spongiosa, causing proliferation of reactive tissue with lymphocytes, eosinophils, and multinucleated giant cells (Fig. 3).
R. de Cristofaro et al. : Case report 629 The differential diagnosis included pigmented villonodular synovitis (PVS) and osteoarticular tubercolosis (TBC). In order to eradicate the lesion with a wide surgical margin an extraarticular periacetabular resection or a hemipelvectomy was considered necessary. Thus, it was elected to use
Pathological features and additional radiological studies
Fig. 3. The biopsy shows fragments of the wall of a cyst, surrounded by reactive tissue. Around the wall of the cyst, reactive giant cells are evident (H & E stain, 200 x original magnification) Fig. 4. Large geodes of the hip in a case of PVS Fig. 5. Typical radiographic features of TBC of the hip. The presence of alterations of the articular cartilage and juxta-articular osteoporosis are signs which distinguish TBC from osseous echinococcosis
medical treatment with mebendazole. At a 2-year follow-up the patient is still in treatment with a stable clinicoradiographic result.
Discussion Hydatidosis represents the most c o m m o n human disease derived from helminth, but skeletal involvement is uncommon (0.5%-4%) [1-3, 7]. In man the infection is caused by the larva of Echinococcus granulosus or, more rarely, Echinococcus alveolaris [1, 3, 7, 14]. This parasite develops its adult cycle in the bowel of a dog and its ova are voided with the feces; man generally is infected by ingesting contaminated vegetables or water. In the human bowel, the envelope of Echinococcus ova is dissolved, releasing a larval tapeworm that reaches the portal venous system and the liver, which is the most common site of infection. On occasion, the larvae pass the first barrier and reach the pulmonary capillaries. Rarely, because of the small diameter of the pulmonary capillaries, the larvae manage to pass this filter, reaching the systemic blood circulation. Thus, bone localization is unusual. In bone, hydatidosis differs from the typical unilocular cyst usually found in extra-osseous sites. Due to the resistance o f the bony tissue, the parasite develops in multiple minute cysts lacking the intense connective tissue reaction which is present in viscera. Within the cancellous bone, where it usually is located, the parasite shows slow growth, forming new vesicles as it extends in affected bone. With time the parasite may destroy the cortex and invade the soft tissues and/or the joint cartilage. The parasite is mostly found in adults, although the initial infestation may occur during childhood. The slow evolution of the disease explains the usually late onset of symptoms. The spine, pelvis, and long bones are the most common sites of involvement [3, 4, 7, 8, 14] ; generally the disease is monostotic but frequently, after destroying the cortex, the parasite invades adjacent skeletal sites.
R. de Cristofaro et al. : Case report 629 Characteristic is the almost total lack of host-tissue reaction: periosteal new bone is usually lacking and reactive hyperostosis is present only in advanced stages. Pathological fractures are important complications and represent an unfavorable prognostic factor, due to the frequent non-union that develops [12]. In the present case the clinicoradiographic differential diagnosis included pigmented villonodular synovitis (PVS). In the hip three different types of PVS are seen [10]: a pseudocoxarthritic form, characterized by articular rim shrinkage, subchondral sclerosis, osteophytosis, and some geodes; a pseudocoxitic form with an impressive reduction of the articular rim, erosions, and geodes in the femoral head and acetabulum; and the third and most frequent form characterized by large geodes located in the femoral neck and more rarely in the femoral head and acetabulum (Fig. 4). In the initial stage the geodes are usually of small dimension and the differential diagnosis with hydatidosis is difficult, because the radiographic aspects and the slow evolution are similar in both lesions. The differential diagnosis is based on the evidence of a sclerosing rim that in PVS delimits the geodes and in hydatidosis only appears in a later phase. A more c o m m o n differential diagnostic possibility includes osteoarticular TBC (Fig. 5). The presence of periosteal reaction, alterations of the joint cartilage and juxta-articular osteoporosis, typical of TBC (in which pathological fractures generally do not occur) represent useful criteria for the diagnosis [3]. Infrequently, especially in the pelvis, diagnosis of chondrosarcoma may be considered. This diagnosis may be suspected when a large destructive lesion invading the soft tissues, with calcification and/or ossification, is present. Chondrosarcoma usually may be excluded because of its very slow evolution and the formation of a sclerotic bony reaction in advanced stages. In long bones the differential diagnosis with fibrous dysplasia or, more rarely, with giant cell tumor sometimes arises. However, in hydatidosis interruption of the cortex with
463 a large mass in the soft tissues and, with epiphyseal lesions, articular involvement with invasion of the adjacent bony segments is frequent. Moreover, in fibrous dysplasia, a "frosted glass" appearance, a sign of primitive or woven bone, is often present. In giant cell tumor, especially in its less aggressive forms, pseudosepta in this osteolytic lesion are evident. Laboratory studies (e.g., Casoni's intradermal test, complement fixation test, haemagglutination test, and eosinophil count) are very useful in establishing the diagnosis. However, false positive and false negative results occur [5]. The usual medical history must lead to a diagnostic suspicion. The presence of an osteolytic lesion similar to hydatidosis in a patient coming from a region where the disease is endemic or working in contact with dogs (the principle source of contamination for man), mandates serious consideration of the diagnosis of hydatid disease. Several medical and surgical therapeutic possibilities exist. Numerous drugs are available (e.g., thymol [5], tartar emetic [5], emetin [5], mebendazole [8]) and different types of surgery are performed according to the site, the extent o f the lesion, and the presence of a pathological fracture. Some authors [2] state that a simple curettage is sufficient therapy, whereas others [1, 8, 9] recommend a more aggressive surgical approach (en bloc resection or amputation), the latter believing that such a treatment is necessary when a pathological fracture occurs and/or the adjacent soft tissues are contaminated [6]. Considering the role of immune factors in the pathogenesis of the disease, treatment by desensitization with hydatid antigen in association with surgery has been tried [4]. This treatment is used in skeletal lesions, but has proved particularly efficient in visceral involvement. During surgery it is mandatory to avoid rupture of the fragile membrane surrounding the cysts with consequent leakage of daughter cysts, leading to unavoidable recurrence. A possible solution consists in flushing the cyst cavity with scoleci-
dal solutions such as formaldehyde [2, 9], ethacridina lactate [6], supersaturated sodium chloride [6, 9], silver nitrate [11, 13], or hydrogen peroxide [5, 9], or by freezing the external wall of the cyst before removal to make it more resistant [13]. In summary, hydatidosis is a common infection that infrequently involves the skeleton. When this happens the prognosis is uncertain because of the possible extension of the disease and serious complications, (e.g., pathological fractures, visceral involvement, neurologic damage from vertebral involvement). For this reason, simple curettage is not sufficient for cure and no medical treatment can surely eradicate the disease. Hydatidosis, in our opinion, should be staged and surgically treated like a malignant tumor (e.g., with wide surgical margins). Medical treatment is useful in association with surgery and remains the only therapy for inoperable lesions. A case of echinococcosis of the hip joint in a 37-year-old man has been reported. In this case the clinicoradiographical features suggested pigmented villonodular synovitis. P r o o f was obtained on the basis of a frozen section on biopsy. The clinical and laboratory characteristics o f hydatidosis were discussed, with emphasis on the medical and surgical treatment of the disorder. Acknowledgement. Supported in part by the Italian National Council of Research, special project "Oncology", grant no. 87.02810.44 and Research Fund of Istituto Ortopedico Rizzoli. References
1. Alldred AJ, Nisbet NW (1964) Hydatid disease of bone in Australasia. J Bone Joint Surg 46 B :260 2. Booz MK (1972) The management of hydatid disease of bone and joint. J Bone Joint Surg 54B:698 3. Da Rin F, Ghirardini GL (1982) Echinococcosi ossea. Rapporto diagnostico con la Tubercolosi osteo-articolare. Atti SERTOT 24:103 4. Duran H, Ferrandez L, Gomez-Castresana F, Lopez-Duran L, Mata P, Brandau D, Sanchez-Barba A (1978) Osseous hydatidosis. J Bone Joint Surg 60A:685 5. Hammouda NA (1974) Hydatid disease of man: a review. Egypt Orth J 9 : 279 6. Hopper J, McLean I (1977) Hydatid dis-
464 ease of the femur. J Bone Joint Surg 59A: 974 7. Jaffe HL (1972) Metabolic, degenerative, and inflammatory diseases of bones and joints. Lea & Febiger, Philadelphia 8. Maggi G (1986) La resezione chirurgica radicale nel trattamento della echinococcosi ossea degli artie del bacino. Chir Org Mov LXXI:33 9. Mnyameh W, Yacoubian V, Bikhazi K
R. de Cristofaro et al. : Case report 629 (1977) Hydatidosis of the pelvis girdle treatment by partial pelvectomy. J Bone Joint Surg 59A: 538 10. Moroni A, Innao V, Picci P (1983) La sinovite villonodulare pigmentosa dell'anca. Giorn It Ortop Traum 9: 347 11. Najarian I, Saidi F (1971) Silver nitrate as a scolecide in the treatment of Echinococcosis of man. Tropenmed Parasitol 2:188 -
12. Puxeddu L (1975) La fratture patologiche nell'echinococcosi ossea. Giorn It Ortop Traum [Suppl] 1 : 183 13. Saidi F, Najarian I (1971) Surgical treatment of hydatid cysts by freezing the cyst wall and installation of 0.5% silver nitrate. New Engl J Med 24:1346 14. Wilner D (1982) Radiology of bone tumors and allied disorders. WB Saunders, Philadelphia
