Giant cell tumor of soft parts. A report of an equine and a feline case.

Masses removed from the superficial fascia of the jugular groove of a 12-year-old Arabian mare and from the femoral canal of a 7 1/2-year-old female cat appeared to be counterparts of the human malignant giant cell tumor of soft parts, even recapitulating the clinical behavior of the respective subgroups. Histologically, both neoplasms contained the characteristic features of the malignant giant cell tumor of soft parts: large multinucleate giant cells, pleomorphic mononuclear giant cells, histiocytes, fibroblasts and fibrocytes that were sometimes sarcomatous, and foci of hemorrhage and necrosis. Ultrastructural characteristics of the giant cells suggest mesenchymal origin with osteoblastic or chondroblastic differentiation.     

Giant cell reaction against the laminated membrane of echinococcus cysts in reindeer lungs.

In 23 pairs of lungs from reindeer two to five years of age, two types of hydatid cysts of Echinococcus granulosus were found: typical well-developed cysts and collapsed degenerated cysts.Collapsed cysts were found in 13 pairs of lungs, well-developed in nine pairs, while both types of cysts were found in one pair of lungs.A giant cell formation was present in the innermost zone of the surrounding adventitial membrane of both collapsed cysts and well-developed cysts. The giant cell reaction seemed to be induced by and directed against the laminated membrane. In the areas of the cysts where the laminated membrane showed a close contact with the adventitial membrane, the giant cells seemed to be actively engaged in the inflammatory process. On the contrary, in the areas of the cysts where the laminated membrane had lost contact with the adventitial membrane, the giant cells were degenerated or necrotic, and the space between the membranes was filled with necrotic cells. In cases where the laminated membrane had been pronouncedly disintegrated, the giant cells were also necrotic or nonexistent.The giant cell reaction which was found even in comparatively young fertile cysts suggests that the reindeer variant of E. granulosus, if such exists, is not especially well-adapted to the reindeer as its intermediate host.     

Benign giant cell tumour of tendon sheaths in a European Lynx (Lynx lynx)

The histological, histochemical, immunohistochemical and ultrastructural features of a benign giant cell tumour (BGCT) of tendon sheaths in a 12-year-old male European lynx (Lynx lynx) are reported herein. The neoplastic mass involved the subcutaneous and inter-muscular tissues of the first, second, third and fourth digit of the left forelimb, from the phalanxes up to the carpus. The tumour appeared as a grey-whitish tissue mottled with darker areas, along with several scattered foci of orange colour. Histologically, the lesion consisted of a mixed population of numerous, multinucleated giant cells and epithelioid or spindle-shaped mononuclear cells embedded in a loose, highly vascular stroma. Neoplastic cells lined cleft formations and synovial-like projections into cystic spaces. No osteoid matrix could be detected. Haemorrhage and necrosis were also observed. The mononuclear and the giant cells were tartrate-resistant acid phosphatase and periodic acid-Schiff positive, being also immunohistochemically reactive for lysozyme and vimentin, with a few cells showing immunopositivity also for alpha-1-antitrypsin. Ultrastructurally, histiocyte-like cells, fibroblast-like cells and multinucleated giant cells were observed, but no virus-like particles could be detected in any of the above cell types. The BGCT of tendon sheaths, a fairly uncommon neoplasm in animals, has not been previously reported in the lynx.     

Appearance of multinucleated giant cells in association with an adenovirus infection in two guinea pigs

In two guinea pigs (five years old, neutered male, and two and a half months old male, respectively) suffering from interstitial pneumonia, multinucleated giant cells were observed histologically in lungs, spleen and liver. The giant cells showed intranuclear, pale basophilic inclusions. Adenovirus could be demonstrated by electron microscopy.The multinucleated cells are supposed to be of histiocytic origin, since they contained variable amounts of haemosiderin in their cytoplasm. Formation of histiocyte-derived syncytia as a result of virus-induced cell fusion is discussed.     

Giant cell tumour of bone in a cat with extraskeletal metastases: pathological and immunohistochemical study

A case of giant cell tumour of bone (GCTb) in the lung and in a subcutaneous mass located in the right flank, with a probable primary origin in the mid-diaphysis of the right tibia, was described in a 8-year-old female cat. Numerous multinucleated giant cells were homogeneously distributed among a population of ovoid or spindle-shaped mononuclear cells. All of them were positive for vimentin suggesting a mesenchymal origin. Spindle-shaped tumour cells resemble fibroblastic cells, showing collagen fibres in their vicinity. Ovoid mononuclear cells are similar to macrophages, with a cytoplasm rich in electron-dense lysosomes. Multinucleated giant cells appear morphologically similar to osteoclasts. These findings are supported for the positive reaction to tartrate-resistant acid phosphatase (TRAP) and lysozyme, encountered only in ovoid and multinucleated giant cells. No immunoreactivity against human oestrogen receptors was observed in the nuclei of any neoplastic cells.     

Primary ureteral giant cell sarcoma in a Pomeranian

An 8-year-old male neutered Pomeranian dog was presented to the Veterinary Teaching Hospital at Oregon State University for surgical treatment of hydronephrosis of the left kidney and a left cranial abdominal mass. A primary ureteral mass was found during exploratory surgery, and the mass was resected and ureteral anastomosis was performed. Cytologic evaluation of the mass revealed 3 distinct cell populations, including a large number of multinucleated giant cells, a moderate number of thin spindle-shaped cells, and cohesive clusters of transitional epithelial cells. The cytologic diagnosis was giant cell sarcoma. The diagnosis was confirmed by histologic examination, and immunohistochemical staining was performed. The spindle-shaped cells and multinucleated giant cells were both immunoreactive for vimentin and spindle-shaped cells for S-100. Tumor cells did not express wide-spectrum cytokeratin, broad-spectrum muscle actin, smooth muscle actin, sarcomeric actin, desmin, BLA36, Mac 387, synaptophysin, neuron-specific enolase, glial fibrillary acid protein, or von Willebrand factor. These findings are most consistent with an anaplastic sarcoma with giant cells. This is the first case report of a primary ureteral giant cell sarcoma in a dog.     

Ultrastructure of a feline extraskeletal giant cell tumor (malignant fibrous histiocytoma)

A subcutaneous extraskeletal giant cell tumor (malignant fibrous histiocytoma) was excised repeatedly from a 9-year-old Domestic Shorthair cat. Ultrastructurally, the mass was composed of fibroblast-like, histiocyte-like, and multinucleated giant cells, and some undifferentiated cells and mononuclear cells intermediate between the fibroblast-like and histiocyte-like cells. Fibroblast-like cells were characterized by abundant well-developed rough endoplasmic reticulum, relatively smooth cytoplasmic membranes, few lysosomal structures, and finely granular chromatin. Histiocyte-like cells resembled immature macrophages. The cell membranes had many villous projections. Rough endoplasmic reticulum varied in quantity. Lysosomes were numerous. Multinucleated giant cells had characteristics of both the fibroblast-like and histiocyte-like cells. No viral particles were seen.     

A clinicopathological study of 52 feline epulides

A retrospective study was performed to characterize 52 new cases of feline epulides between 1995 and 2001, with clinical and pathological results classified according to Head's histopathologic criteria for canine epulides. The incidence of the fibromatous, acanthomatous, ossifying, and giant cell epulis were respectively 57.7% (30/52), 7.7% (4/52), 5.8% (3/52), and 28.8% (15/52). Giant cell epulides presented significant differences in clinical behavior compared with the fibromatous type, including rapid growth (P < .0001), presence of ulcerative changes (P < .01), and rapid recurrence after surgery (P < .01) from which euthanasia was judged necessary in 4 cases. Fifteen giant cell epulides were additionally examined in order to characterize the lesion both histochemically and immunohistochemically and to investigate the origin of the multinucleated giant cells (MGCs). Van Gieson staining showed osteoid and woven bone formation in 11 cases. Both the MGCs and a fraction of the mononuclear cells were positive for vimentin, tartrate-resistant acid phosphatase (TRAP), a commonly accepted marker for osteoclasts, and the polyclonal antibody receptor activator of nuclear factor kappabeta (RANK), a cytokine leading to the differentiation of osteoclast progenitors into mature osteoclasts in presence of its ligand. MGCs were negative for smooth muscle actin, MIB-1, and factor VIII. The giant cell epulis may be a variant of the fibromatous and ossifying epulis in which extensive ulceration and inflammation results in increased osteoclastic activity. The osteoclast-like giant cells are most likely formed from a monocyte/macrophage-like osteoclast precursor that differentiates into osteoclasts under the influence of mononuclear osteoblast-like stromal cells.     

Feline vaccine-associated fibrosarcoma induced by aluminium compound in two cats: short communication

Two cases of feline vaccine-associated fibrosarcoma (FVAF) are reported. The excised tumours were both characterised as well circumscribed, subcutaneous, firm and white with central necrosis. Histopathologically, they consisted of well-differentiated and variably sized and shaped anaplastic cells, characterised by marked nuclear and cellular pleomorphism including giant cells. The mitotic activity was low. Aluminium was demonstrated in the central necrosis and giant cells. Neoplastic cells were positive for vimentin and negative for desmin and cytokeratin. The presence of feline sarcoma virus and feline immunodeficiency virus could not be detected by PCR in either case.     

Malignant fibrous histiocytoma (giant cell type) associated with a malignant mixed tumor in the salivary gland of a dog

A 12-year-old male Boxer dog presented with a 5 x 5 x 7-cm partially encapsulated mass in the right mandibular salivary gland. Histologically, the mass was composed of neoplastic epithelial and mesenchymal cells. The mesenchymal component consisted of two cell populations arranged in different patterns: coalescing nodules of neoplastic mononuclear cells with rare osteoid and numerous osteoclastlike giant cells; and sheets of neoplastic spindle cells intermingled with neoplastic epithelial cells and containing osteoid and well-formed bone trabeculae lined by osteoblasts and few osteoclastlike giant cells. On the basis of these histological features, two malignant salivary tumors were diagnosed: a malignant fibrous histiocytoma (giant cell type) and a malignant mixed tumor. Immunohistochemical studies demonstrated keratin 5 and 8 expression by the neoplastic epithelial cells, indicating a probable salivary ductal origin, and vimentin expression by all mesenchymal elements, suggesting a fibroblastic line of differentiation.     

Enteritis associated with porcine circovirus 2 in pigs

This report describes the diagnosis of porcine circovirus 2 (PCV2)-associated enteritis in 6 weaned pigs without postweaning multisystemic wasting syndrome by histopathology, virus isolation, and in situ hybridization. The most unique lesions were granulomatous inflammation affecting Peyer's patches, characterized by infiltrates of epithelioid macrophages and giant multinucleated cells. Large, multiple, basophilic or amphophilic, grape-like intracytoplasmic inclusion bodies were often seen in the cytoplasm of histiocytic cells and giant multinucleated cells. No microscopic lesions were observed in the lymphoid tissue, such as lymph node, spleen, and tonsil. A strong hybridization signal for PCV2 was detected in the cytoplasm of histiocytes and giant multinucleated cells in Peyer's patches. Porcine circovirus 2 was isolated from homogenates of the small and large intestines in 2 weaned pigs. The presence of diarrhea and granulomatous enteritis, and abundant PCV2 DNA associated with the microscopic lesions is suggestive of PCV2-associated enteritis. Thus, PCV2-associated enteritis could be a distinct clinical manifestation of PCV2.     

Trophoblast-like cells in the tissues of porcupines (Erethizon dorsatum)

During development and subsequent field evaluation of an oral vaccinia-rabies glycoprotein (V-RG) recombinant virus vaccine, 53 adult porcupines (Erethizon dorsatum; 38 females and 15 males) were examined. Microscopic examinations revealed the presence of giant epitheloid cells in various tissues (adrenal glands, spleen, liver, and lungs) of 4 (11%) female animals. These giant cells were approximately 20 times the size of the surrounding cells of the parenchyma. The cells were found singly and were not associated with any inflammatory cellular infiltrate and appeared to be located within vascular lumina. Morphologically these cells were typical of uterine epitheloid trophoblasts. This is the first record of the presence of trophoblast-like cells in nongenital tissues of porcupines.     

Thymic granulomatous lesions in pigs

Rare cases of thymic granulomatous lesions were found in pigs. The lesions consisted of epithelioid cells, multinucleated giant cells, and lymphocytes. Such lesions also were observed in the mesenteric lymph nodes, spleen, kidney, and stomach. The cytoplasm of the majority of giant cells and some epithlioid cells was periodic acid-Schiff (PAS) positive. All cells were positive for vimentin, lysozyme, and desmin. Ultrastructurally, the giant cells were rich in organella and attached to adjacent epithelioid cells by membrane interdigitation. The cells included numerous coated vesicles and granules. No etiologic pathogen, including porcine circovirus type 2, was detected in the lesions. This is the rare case of idiopathic thymic granulomatous lesion in pigs.     

Spontaneous adenocarcinoma with giant cell formation in the accessory sex glands in a male Sprague-Dawley rat

In this study, we report the features of an adenocarcinoma with giant cell formation spontaneously occurring in the accessory sex glands of a male 10-month-old Sprague-Dawley rat. A milky white mass was found in the region corresponding to the left seminal vesicle and the left coagulating gland. Histologically, tumor cells exhibited diverse growth patterns, including glandular/trabecular, cystic, and sheet-like growth areas. The tumor cells were pleomorphic, with round- or oval-shaped nuclei and abundant eosinophilic cytoplasm. Mitotic figures were occasionally observed. Giant cells were also prominent in the sheet-like growth area, with intracytoplasmic vacuoles containing eosinophilic material. The stroma was rich in collagen fibers and fibroblasts. Numerous inflammatory cells were observed in the glandular and cystic lumina and stroma. Immunohistochemically, the tumor cells were positive for cytokeratin AE1/AE3 and proliferating cell nuclear antigen. In the sheet-like growth area, some of the tumor cells and giant cells were positive for vimentin in the cytoplasm adjacent to the nucleus. Electron microscopy revealed that the tumor cells contained a small number of mitochondria and rough endoplasmic reticulum, and had no basement membrane or desmosome. The giant cells occasionally contained variably sized intracytoplasmic lumina and globular filamentous bodies, probably corresponding to vimentin. Considering these morphological features, the tumor was diagnosed as an adenocarcinoma with the formation of giant tumor cells originating from the male accessory sex glands.     

Tail root osteosarcoma in a chipmunk (Tamias sibiricus)

An 8-year-old chipmunk (Tamias sibiricus) showed a mass on the tail root. Histologically, the excised mass showed proliferation of spindle-to-polyhedral cells and abundant multinucleated giant cells, with the production of neoplastic osteoid. Immunohistochemically, neoplastic cells were positive for vimentin and weakly positive for osteocalcin. Osteoid was also positive for osteocalcin. This tumor was diagnosed as a giant cell-type osteosarcoma. This is the first case report of osteosarcoma in a chipmunk.     

Ovarian choriocarcinoma in the mouse

Choriocarcinoma is one of the rarest ovarian tumors in any animal species. This paper describes the gross and microscopic appearance of seven such neoplasms in B6C3F1 mice. Mean age at death was 47 weeks. Tumors were described at necropsy as dark or hemorrhagic cystic lesions. On microscopic examination tumors were composed of hematocysts, intercellular hemorrhage, and cytotrophoblasts, syncytiotrophoblasts, and/or trophoblastic giant cells. Cytotrophoblasts, syncytiotrophoblasts, and occasional giant cells were present in three cases while the other four tumors contained only trophoblastic giant cells.     

B-cell immunoblastic lymphoma with multinucleated giant cells in a cat

A 10-year-old male mixed breed cat died after six months history of intermittent vomiting and weight loss. At necropsy, large white-colored foci were found in both kidneys, and whitish thickening of the gastric wall was present at the pyloric part of the stomach. Histopathological examination revealed that both lesions consisted of proliferation of large-sized neoplastic lymphocytes intermingled with multinucleated giant cells. Immunohistochemically, the neoplastic cells were positive for both B-cell antigen receptor complex (CD 79 alpha cy) and MHC class II, although multinucleated giant cells were negative. The present case was diagnosed as B-cell immunoblastic lymphoma with multinucleated giant cells.     

Role of cell cycling and polyploidy in placental trophoblast of different mammalian species

The trophoblast cells that take part in placenta formation are characterized by different modes of multiplication of their genome that largely designates their eu- or aneuploidy level. The two main ways of genome multiplication are described in different degree: (a) endoreduplication that involves almost complete shutdown of mitosis and (b) reduced mitosis (‘endomitosis’) in which, by contrast, entry into mitosis and the passage of its initial stages is a prerequisite of genome multiplication. Endoreduplication observed in the trophoblast giant cells (TGC) in a range of mammalian species implies uncoupling of DNA replication from mitosis achieved by reduction of mitotic Cdk activity. The key role in the regulation of endoreduplication and endomitosis play activity of APC/C complex, geminin and E2F family. A programme of genome multiplication and cell cycle progression may include depolyploidization achieved by specific mitotic or non-mitotic (amitotic) division of the giant nucleus. In some mammalian species (Rodents), this process represents the final step of the giant cell lifespan that coincides with complete cessation of cell or genome reproduction. Meantime, in other species the process may take part in cell reproduction during lengthy pregnancy. The dynamics of fox and human polyploidization is similar by the possibility of a simultaneous increase in the proportion of endopolyploid and low-polyploid cells. Reduced mitoses, endoreduplication and depolyploidization appear to be an evolution strategy allowing to generate the functionally different trophoblast cell populations depending of the lifestyle of life of the animal species. Some placental pathologies may be accounted for disturbance of the programme of the cell/genome reproduction of the giant and low-ploid cell populations.     

Primary cardiac fibrosarcoma in a dog

A primary cardiac fibrosarcoma in the right atrium of a 6-year-old Chihuahua dog is described. At necropsy, there was a firm, whitish and spherical mass in the right atrium. Histopathologically, the mass had moderate cellularity composed of spindle-shaped cells with scattered multinucleated giant cells. The tumor cells were arranged in interwoven bundles and sheets in the collagenous stroma. No metastases were observed. Ultrastructurally, the tumor cells mainly consisted of fibroblasts. Multinucleated giant cells did not have any certain organelles that would indicate a higher order of differentiation. Primary cardiac sarcomas in dogs are extremely rare.     

Giant cell tumor of the bone in a scarlet macaw (Ara macao)

A 6-mo-old female scarlet macaw (Ara macao) was presented after a 2-mo period of anorexia and weakness. The bird was reluctant to fly 1 wk before referral due to a painful left wing. Physical examination revealed a firm swelling around the left shoulder. On radiographs, the diaphysis and proximal metaphysis of the left scapula were radiolucent. Computer tomography revealed an osteolytic process, suggestive of a bone tumor, affecting the left scapula. Cytology of a fine needle aspiration biopsy of the mass showed erythrocytes, a proliferation of spindle-shaped mesenchymal cells, and multinucleated giant cells (osteoclasts) suggestive of a giant cell tumor. The left wing, including the scapula, was amputated. The bird showed a fast recovery but died 1 hr later. Findings during the pathological examination were compatible with shock due to blood loss. The shoulder process was characterized as a giant cell tumor. To our knowledge, this is the first complete report of a giant cell tumor of the bone in a bird.