Telangiectatic Osteosarcoma in the Dog

Abstract

Osteosarcoma is a malignant neoplasm of bone that contains at least a sarcomatous stroma and tumor osteoid. It may contain various quantities of neoplastic fibrous connective tissue, cartilage, and bone as well. Histologic classifications of this tumor are based on the proportions of these components. The three most common histologic types are osteoblastic, fibroblastic and chondroblastic [l, 2,4].A rare variant described in both man and dog is the telangiectatic osteosarcoma, also called A recent review of 25 selected cases of telangiectatic osteosarcoma in man led to the conclusion that the prognosis with this variant is bleaker than with other types of osteosarcomas [3]. It has been described as inevitably fatal in the dog [5].Dog 1, an 8-year-old female German Shepherd, had right shoulder and foreleg lameness and a subcutaneous mass in the dorsum of the neck. A skeletal radiologic survey showed a normal thorax and an osteolytic lesion of the right scapula ( fig. I). Many neutrophils in the neck mass and highly undifferentiated neoplastic cells with a few multinucleated giant cells in the scapular lesion were seen in Giemsa-stained smears of needle aspirates. The preliminary diagnoses were an abscess in the neck and undifferentiated sarcoma in the scapula. A fleshy mass with a necrotic center and a portion of the scapulo-humeral joint capsule were removed surgically and the dog was placed on a regime of chemotherapeutic drugs, Adriamycin (Doxorubicin, Adria Labs, Wilmington, Del.) and DTIC (Dacarbazine, Dome Labs, West Haven, COM.).Histologic examination showed a highly vascular mass with large and small vascular spaces lined by large neoplastic cells and masses of large anaplastic malignant cells with numerous mitotic figures (fig. 2, 3). Necrosis, hemorrhage, multinucleated cells, and some fibrosis were seen. The original diagnosis was hemangiosarcoma, but this diagnosis was changed to telangiectatic osteosarcoma when osteoid ( fig. 3) was found at reexamination.The dog did not respond to chemotherapy, and was killed. At necropsy, a bloody friable 9 X 8-cm mass was found in the right scapula and the head of the humerus.Histologic examination showed the same changes as described above and confirmed the diagnosis of telangiectatic osteosarcoma. 398Brief Communication Dog 2, a 6%-year-old female Chihuahua cross, presented with a mass in the left temporal region and a missing left rear leg, amputated three years earlier because of osteomyelitis. Radiologic examination showed lysis of the zygomatic arch and the tip of the coronoid process of the mandible. A piece of sequestered bone also was present. Initial surgery showed necrotic tissue with a bony sequestrum. The lesion was considered traumatic or infectious and was treated accordingly. A biopsy taken one month later showed, on histologic examination, areas of fibrosis, hemorrhage, aggregates of undifferentiated neqplastic sarcomatous cells with high mitotic activity and some osteoid. The diagnosis was osteosarcoma with hemorrhage and fibrosis. Palliativ...

Primary Hemangiosarcoma of the Humerus in a Maltese Dog

“…Furthermore, it is necessary to distinguish osseous HS from telangiectatic osteosarcoma, which is characterized by osteolysis, many blood filled spaces, and osteoid formation [8,16]. These findings are very similar to those of HS in bones, but without osteoid formation [8,16]. In our case, osteoid formation was not found in the sarcoma tissue, and therefore telangiectatic osteosarcoma was also excluded.…”

“…These findings indicated that the humerus was the primary site, and not secondary metastasis from other organs or tissues with HS. Furthermore, it is necessary to distinguish osseous HS from telangiectatic osteosarcoma, which is characterized by osteolysis, many blood filled spaces, and osteoid formation [8,16]. These findings are very similar to those of HS in bones, but without osteoid formation [8,16].…”

Vertebral telangiectatic osteosarcoma in a dog

“…The major diagnostic criteria for TOS are lytic lesions of bone with no bone formation and the presence of many blood‐filled spaces lined by large undifferentiated tumor cells. TOS is characterized by malignant osteoblasts that produce a minimum of osteoid 13 . In the dog in this case, radiographic and histologic examination revealed the characteristic lesions described above.…”

“…The 5 designated groups were a) medullary and subperiosteal, b) telangiectatic (TOS), c) sclerosing, d) periosteal, and e) fibrosarcoma (medullary and subperiosteal). Canine osteosarcomas tend to be classified into histologic subtypes based on the quality and quantity of extracellular matrix (osteoblastic, chondroblastic, 9,10 and fibroblastic 11 ), the degree of differentiation (poorly differentiated or undifferentiated), the relative abundance of giant cells (giant‐cell, giant‐cell‐rich, and osteoclast‐rich 12 subtypes), and the dominance of blood‐filled cystic lesions (telangiectatic 13–15 ). A sclerotic subtype also has been described in dogs 16,17 .…”

Prognostic Significance of a New Histologic Grading System for Canine Osteosarcoma

“…The histologic features of OS, however, vary greatly from tumor to tumor and within tumors themselves. Multiple types of well-and undifferentiated cells and matrix are often observed in a single tumor, 16,25,26 which may be why subclassification of OS has not yielded significant differences in the prognosis of human and canine OS. 18,40 In human OS, histologic grading of the tumor, in contrast to subclassification, serves as a good indicator for prognosis.…”