Multilobular tumour of bone of the thoracic wall in a cat

Multilobular osteochondrosarcoma of the vertical ramus of the mandible in a cat

A 7-year-old castrated male domestic shorthair cat presented with locked jaw syndrome and firm swelling in the right temporal region of the skull. A computed tomography (CT) scan showed a heavily calcified mass of the right coronoid process of the mandible with a popcorn appearance, consistent with a multilobular osteochondrosarcoma. The zygomatic arch was displaced laterally and ventrally due to the mass effect. The temporomandibular joint was not involved. Surgical treatment was performed and consisted of the removal of the zygomatic arch and the vertical ramus of the mandible. It was possible to open the mouth normally immediately after surgery. Recovery was uneventful. Histological examination of the mass confirmed multilobular osteochondrosarcoma. This type of tumor is rarely encountered in dogs, and a literature search reveals only two cases in cats: one arising from the skull and one from thoracic wall. This case report documents the first description of a multilobular osteochondrosarcoma of the mandible in a cat.

Multilobular tumor of bone on the forehead of a guinea pig

Multilobular tumor of bone (MLTB) is an infrequent, slow-growing, bone neoplasm formed predominantly on the head. These tumors can behave as malignant neoplasms clinically and pathologically and can metastasize occasionally. No cases of MLTB in rodents have been reported, to our knowledge. We describe a novel case of an MLTB in a guinea pig. An adult guinea pig had an exophytic mass fixed on the frontal bone, maxilla, and nasal bone. On radiography, the mass had a spherical contour and variable density and was formed on the surface of the cranial bones. The mass was excised surgically. The cut surface was light-yellow to milky-white and had a granular texture with fine fibrous septa. Histologically, the neoplasm had a multilobular pattern, which consisted of many islands of bone and/or cartilage matrix surrounded by small cells and separated by fibrous septa, which closely resembles the equivalent neoplasm in dogs.

Catheter occlusion of the dorsal sagittal sinus-confluens sinuum to enable resection of lateral occipital multilobular osteochondrosarcoma in two dogs

CASE DESCRIPTION

A 6-year-old neutered male mixed-breed dog (dog 1) and 5-year-old neutered male Boston Terrier (dog 2) were evaluated because of lateralized multilobular osteochondrosarcoma (MLO) of the occiput.

CLINICAL FINDINGS

Diagnostic imaging revealed proliferative bony occipital masses in both dogs and a nodule in the right caudal lung lobe of dog 1. For both dogs, MRI revealed intact flow through the dorsal sagittal sinus (DSS) into 1 transverse sinus.

TREATMENT AND OUTCOME

In dog 1, a 4F balloon catheter was introduced into the DSS to the confluens sinuum (CS) and inflated over 16 hours to occlude venous flow. The mass with the CS was removed 24 hours later, and the skull was reconstructed. The dog was discharged from the hospital 2 days after surgery and survived 17 months before euthanasia because of metastasis. In dog 2, balloon catheter insertion into the DSS failed, and a 3.5F rubber catheter was placed up to the CS to occlude flow. The occiput with MLO was removed 48 hours after catheterization, and the skull was reconstructed. Dog 2 was discharged from the hospital after 3 days and was doing well 15 months later.

CLINICAL RELEVANCE

Findings for these 2 dogs suggested that deliberate preoperative occlusion of the DSS and CS allows successful resection of occipital neoplasms across the midline. Without prior occlusion of the DSS, development of lethal cerebral edema would have been likely. Gradual balloon catheter occlusion of the CS may facilitate challenging occipital mass excisions.

Malignant mesenchymoma in the nasal cavity of a bull

A 4-year-old bull was presented with facial distortion and abnormal respiratory noise. Endoscopically, a proliferative mass was found obliterating the left nasal cavity and a tumour was suspected. The head was examined after slaughter and there was a well-circumscribed solid structure (15×12×6 cm) extending into the paranasal sinus, the choanal region and the bones of the orbit, with focal penetration of the nasal septum. Microscopically, the mass consisted of well-differentiated trabeculae of woven and lamellar bone, areas of chondromyxomatous, immature and mature cartilaginous tissue, and regions with irregular whorled spindle cells. Tissue differentiation of the mass was variable. Centrally, there was osseous differentiation with an outermost fibromatous area resembling a zone of endochondral ossification. There was suppurative and ulcerative inflammation where the tumour extended through the hard palate and into the pharynx. A nasal malignant mesenchymoma was diagnosed on the basis of these features.