Skeletal Radio1 (1991) 20:311-314

Skeletal Radiology

Case report 673 Si-Kwang Liu, D.V.M., Ph.D., and Christopher Thacher, D.V.M. The Animal Medical Center, New York, New York, USA

Radiological studies

Clinical information A 4-year-old, 70 kg, male Great Dane dog was studied for lameness in a left rear limb and a firm, painful swelling of the left metatarsal region of several weeks' duration. The lameness and swelling were partially responsive to antibiotic treatment. On physical examination, a palpable mass approximately 1.5 x 3.5 cm was noted with tenderness to palpation but no associated redness. Radiographs o f the left metatarsus revealed an expanding, lyric lesion in the third metatarsal bone. Bulging of the anterior surface corresponded to the palpable mass. The cortex was thin and eroded in areas with minimal periosteal reaction and sclerosis in the proximal region of the third metatarsal bone (Fig. 1, 2). A surgical biopsy of the lesion was performed,

Fig. l. A frontal plane view roentgenogram shows an expanding, lyric lesion with a minima1 intralesional density and a sclerotic rim in the proximal portion of the left third metatarsal Fig. 2. A lateral view roentgenogram shows a bulging, thin, and eroded cortex with minimal intralesional density and periosteal reaction is the left third metatarsal

Address reprint requests to: S.-K. Liu, D.V.M., Ph.D., Animal Medical Center, 510 East 62nd Street, New York, NY 10021, USA

9 1991 International Skeletal Society


Diagnosis: Telangiectic osteogenic sarcoma The lesion contained a large a m o u n t of blood and some solid tissues which were obtained by curettage. The pathological specimens consisted of numerous, irregular, firm, dark-purple and pinkish tissues from

S.-K. Liu and C. Thacher: Case report 673 a few m m to 1.2 cm in diameter. Microscopically, the curetted tissues consisted of blood spaces outlined by fibrous, osteoid, or granulation tissue (Fig. 3, 4). Some of the spaces were partially lined by an indistinct endothelium. Also present were some solid areas of multinuclear giant cells (Fig. 5) and fibrous, osteoid, or os-

seous tissues. A diagnosis of aneurysreal bone cyst was made based on the microscopic findings of the biopsied specimens. One m o n t h following the initial biopsy, the lesion was further curetted and the cavity filled with autogenous cancellous bone graft, obtained from the left iliac crest. The

Pathological studies

Fig. 3. Aneurysmal spaces with granulation tissue and trabecular septae are noted Fig. 4. Blood spaces lined by an indistinct endothelium, fibrous and osteoid tissues are evident Fig. 5. Solid area of multinuclear giant cells and scanty fibrous stroma is visible Fig. 6. Closely packed sarcomatous cells are present with mitotic figures and scanty osteoid formation Fig. 7. Irregular osteoid formation, giant cells, and fibrous stroma are observed

S.-K. Liu and C. Thacher: Case report 673 material removed by curettage was again submitted for histopathological analysis, and the pathological diagnosis of this sample was malignant giant cell tumor with osteosarcomatous transformation. Postoperatively, the surgical incision healed without incident, and the lameness improved substantially for several weeks. Approximately 10 weeks following the second curettage and placement of the bone graft, the dog was again examined for a large, fluctuant swelling of the left metatarsal region and increased lameness. A fine needle aspirate of the fluctuant mass was performed, and 12 cc of serosanguinous fluid were removed, which produced no bacterial growth with culture and sensitivity testing. Radiographs revealed marked lysis of both the third metatarsal bone and the cancellous bone graft. An extensive curettage was performed on the lesion. Numerous, irregular, dark-purple, firm specimens from a few mm to 1.5 cm in diameter were obtained for histopathological study. In addition to the previous microscopic findings, solid areas of anaplastic sarcomatous cells (Fig. 6) were present together with neoplastic osteoid tissue (Fig. 7). Based on these histopathological findings, a definite diagnosis of telangiectatic osteogenic sarcoma was made. The dog was euthanized by the owner's request 1 week after final diagnosis. The body was not available for autopsy.


The initial clinical, radiological, and histopathological presentation of this case, including the gross swelling over the left third metatarsal bone, the radiographic appearance of expansion and lysis, and the findings on the initial biopsy (gross and microscopic) of numerous blood spaces separated by fibrous, osteoid, or osseous septae, with the presence of numerous multinuclear giant cells, is compatible with a diagnosis of an aneurysmal bone cyst. Aneurysmal bone cyst is a benign vascular lesion of bone containing blood-filled spaces and solid areas of spindle cell stroma with osteoid and multinucle-

313 ar giant cells and has been reported in humans [1, 10], cats [6], and dogs [5]. Curettage of the lesion and packing the cyst cavity with cancellous bone graft is the treatment of choice for aneurysmal bone cyst and is often curative. This lesion was more progressive, however, and further biopsy and curettage 10 weeks after the initial curettage and graft insertion produced specimens consisting of aneurysmally dilated spaces, islands of sarcomatous cells, and neoplastic osteoid, characteristic of telangiectatic osteogenic sarcoma. These features have been well described in humans [2, 3, 8]. Aneurysmal bone cyst and telangiectatic osteogenic sarcoma may have similar radiographic and histopathological appearances. Two cases have been reported in which an aneurysmal bone cyst was erroneously diagnosed as an osteosarcoma [4]. In contrast, 9 of the 25 cases of telangiectatic osteogenic sarcoma included in another study were originally considered benign, 3 of which were identified as aneurysmal bone cysts [2]. Areas with the typical microscopic appearance of an aneurysmal bone cyst may be observed, especially in the peripheral portions, of a lesion otherwise characteristic of a telangiectatic osteogenic sarcoma [3]. Neither radiographic nor clinical findings alone should be relied upon to distinguish definitively aneurysmal bone cyst from telangiectatic osteogenic sarcoma. The likelihood of a misdiagnosis of an aneurysmal bone cyst and a telangiectatic osteogenic sarcoma, or vice versa, is considerable. The presence of anaplastic stromal cells with numerous mitotic figures and osteoid formation by the sarcomatous spindle cells are essential to label a lesion correctly as an osteogenic sarcoma [3]. Although osteosarcoma has been reported to account for 46% of all canine bone tumors, telangiectic osteogenic sarcoma rarely occurs in the dog [7]. In one study, the age distribution of 398 dogs with osteosarcoma ranged from 5 months to 17 years; the mean age was 8.2+0.7 years, and there was a sharp increase in risk from 7 to 10 years 51% of the dogs developed the tumor during this time. The ratio of males to females was 1.2. Osteosarcoma tends

to occur in large breed dogs such as Great Danes, German shepherds, St. Bernards, boxers, retrievers, Irish setters, and Doberman pinschers. These seven breeds accounted for 63% of the total 398 dogs, while small dogs under 25 pounds comprised only 4%. Osteosarcoma has a predilection for long bones: 73% of the tumors arose in the appendicular skeleton (44% in the foreleg and 29% in the hind limb), and 27% of the tumors originated in the axial skeleton. The distribution in the four major weightbearing bones was the following: radius 20%, humerus 19%, femur 17% and tibia 11%, thus accounting for 67% of the total. Of those of the axial skeleton, 8% of the osteosarcomas were located in the skull, 5% in the ribs, and 10% in vertebrae [5]. Canine osteosarcoma generally involves the proximal and distal ends of the long bones [11], while osteosarcoma associated with metallic implants may be found in the diaphysis [9]. The diaphysial, expanding, lyric lesion involving the metatarsal in this 4-year-old Great Dane lies at an unusual site for an osteosarcoma. The radiographic appearance of a predominantly lyric lesion with minimal intralesional sclerosis and a sclerotic rim at its proximal portion is comparable with that of radiographs of telangiectatic osteogenic sarcomas in human patients [31. In summary, a case is presented of a telangiectatic osteogenic sarcoma involving the left third metatarsal of a 4-year-old male Great Dane dog. Radiographs revealed a diaphyseal, expanding, lytic lesion with minimal intralesional sclerosis and a sclerotic rim in the proximal portion. The lesion contained a large amount of blood. The biopsy specimens consisted of spaces which were outlined by fibrous osteoid or granulation tissue. There were islands of multinuclear giant cells and/or fibrous osteoid tissue. A diagnosis of aneurysreal bone cyst was made. The lesion was treated by curettage and insertion of cancellous bone graft but was progressive 10 weeks after treatment. The lesion was further curetted, and these biopsy specimens consisted of aneurysmally dilated spaces and areas of anaplastic sarcomatous cells with mitotic figures and osteoid pro-

314 d u c t i o n , characteristic o f telangiectatic osteogenic sarcoma. The dog was e u t h a n i z e d as the o w n e r requested; a n a u t o p s y was n o t performed.

References 1. Campanacci M (1976) Aneurysmal bone cysts: a study of 127 cases. Ital J Orthop Traumatol 2 : 341 2. Farr GH, I-Iuvos AG, Marcone RC, etal. (1974) Telangiectatic osteogenic sarcoma: a review of 28 cases. Cancer 34:1150

S.-K. Liu and C. Thacher: Case report 673 3. Huvos AG, Rosen G, Bretsky SS, Butler A (1982) Telangiectatic osteogenic sarcoma: a clinicopathologic study of 124 patients. Cancer 49:1679 4. Kahn LB, Wood FW, Ackerman LV (1969) Fracture callus associated with benign and malignant bone lesions and mimicking osteosarcoma. Am J Clin Pathol 52:14 5. Liu SK (1990) Neoplasms of bone. In: Whittick WG (ed) Canine orthopedics. Lea&Febiger, Philadelphia, p 881 6. Liu SK, Dorfman HD, Patnaik AK (1974) Primary and secondary bone tumors in the cat. J Sm Anita Pract 15:141 7. Liu SK, Dorfman HD, Hurvitz AI, Patnaik AK (1977) Primary and secondary

bone tumors in the dog. J Sm Anim Pract 18 : 313 8. Matsuno T, Unni KK, McLeod RA, etal. (1976) Telangiectatic osteogenic sarcoma. Cancer 38:2538 9. Sinibaldi K, Rosen H, Liu SK, DeAngelis M (1976) Tumors associated with metallic implants in animals. Clin Orthop 118:257 10. Spjut HJ, Dorfman HD, Fechner KE, Ackerman LV (1971) Aneurysmal bone cyst. In: Tumors of bone and cartilage. Armed Forces Institute of Pathology, Washington, DC, p 357 11. Wolke RE, Nielsen SW (1966) Site incidence of canine osteosarcoma. J Sm Anim Pract 17:489

Case report 673: Telangiectic osteogenic sarcoma.

A case is presented of a telangiectatic osteogenic sarcoma involving the left third metatarsal of a 4-year-old male Great Dane dog. Radiographs reveal...
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