Occult subchondral osseous cyst-like lesions of the equine tarsocrural joint

OBJECTIVE: To report the clinical signs, diagnosis, management, and outcome of horses with occult sub-chondral osseous cyst-like lesions of the tarsocrural joint. DESIGN: Retrospective study. ANIMALS: Twelve horses with subchondral osseous cyst-like lesions (SOCLs) in the tarsocrural joint. METHODS: Information about history, examination findings, diagnostic techniques, and surgical procedures as obtained from medical records. Outcome was determined by patient re-evaluation and telephone communication with the referring veterinarian, owner, or trainer. RESULTS: Horses were aged from 3 to 29 years. Lameness (2 weeks to 1 year) varied from moderate to severe. Synovial fluid analyses (9 horses) yielded changes consistent with suppurative inflammation and positive bacterial culture was obtained in 4 horses. Eight of 9 horses that had intra-articular analgesia had a dramatic reduction in lameness. No abnormalities were detected on tarsal radiographs in 10 horses. Scintigraphy identified foci of increased radiopharmaceutical uptake in the distal tibia or talus of all horses, and the lesion was further characterized by computed tomography in 7 horses. SOCLs were identified in the medial malleolus (5), intertrochlear groove of the talus (4), lateral malleolus (2), and distal intermediate ridge of the tibia (1). One horse was euthanatized, 6 horses had surgical debridement, and 5 horses were managed conservatively. Four horses treated surgically (67%) returned to soundness. Conservatively treated horses continued to exhibit lameness but 2 were sufficiently sound for light pleasure riding. CONCLUSIONS: Occult lesions of the tarsus not visible on radiographs can be detected by computed tomography and scintigraphy and may be a source of lameness. CLINICAL RELEVANCE: SOCL, possibly of septic origin, should be a differential diagnosis for persistent lameness localized to the tarsocrural joint without radiographic abnormalities. Surgical debridement of the lesions may offer the best prognosis for a return to athletic soundness.     

Comparison between radiological and magnetic resonance imaging lesions in the distal border of the navicular bone with particular reference to distal border fragments and osseous cyst-like lesions

Reasons for performing study: There are no data concerning the accuracy of conventional and computed or digital radiography for evaluation of the equine foot. Objectives: To compare conventional film‐screen and computed radiography with magnetic resonance imaging (MRI) for detection of distal border fragments of the navicular bone; and to establish which type of fragment was more likely to be detected radiologically. Methods: Horses were included if forelimb lameness was localised to the foot and both radiography and high‐field MR images had been acquired. Horses were divided into 2 groups based on acquisition of conventional (Group A) or computed (Group B) radiographs. The presence of distal border fragments was recorded. From MR images, distal border fragments were graded based on their size and changes in signal intensity in the adjacent navicular bone. Sensitivity and specificity of conventional and computed radiography for detection of fragments were calculated using MRI as the gold standard. A Chi‐squared test was used to test for associations between specific radiological and MRI findings in the distal border of the navicular bone. Results: In Group A 46 and 18 fragments were identified on MR and radiographic images, respectively; in Group B 45 and 17 fragments were seen. There was no significant difference between computed and conventional radiography. Grades 4 and 5 fragments or large‐sized fragments were identified most frequently; low‐grade fragments were unlikely to be observed. There was a significant correlation between radiological and MRI abnormalities of the distal border of the navicular bone. Conclusions: Conventional and computed radiography had similar, rather low sensitivity for identification of distal border fragments of the navicular bone, but specificity was high. Large‐sized and high‐grade fragments were most likely to be identified radiologically. Potential relevance: Fragments observed radiologically are likely to be associated with other pathological abnormalities of the distal border of the navicular bone.     

Diagnostic investigation of an unusually large osseous cyst-like lesion of the radial carpal bone

A 10-year-old Irish Sports Horse presented for intermittent, fluctuating lameness of the left forelimb. Nuclear scintigraphy, radiography and computed tomography identified a large osseous cyst-like lesion (OCLL) occupying approximately 50% of the radial carpal bone with an articular communication to the antebrachiocarpal joint. A transcortical surgical approach was used to curette the lining of the lesion prior to injection with triamcinolone acetonide. This imaging report describes the detailed diagnostic findings of an unusually extensive OCLL in the radial carpal bone.     

Subchondral cyst-like lesions in the distal portion of the radius of four horses

Four horses with subchondral cyst-like lesions in the medial radial facet of the distal portion of the radius were examined. Joint effusion and signs of pain from flexion of the antebrachiocarpal joint were not observed, but lameness was observed in 3 of the 4 horses. Regional nerve blocks and intra-articular anesthesia were used to localize the lesions, and conservative treatment resulted in soundness for performance.     

Nonsurgical treatment of cubital subchondral cyst-like lesions in horses: seven cases (1983-1987).

Subchondral cyst-like lesions of the cubital joint were diagnosed in 7 horses at the teaching hospital between 1983 and 1987. Diagnosis of the lesions was made by administration of intra-articular local anesthesia and/or radiographically. Initial treatment for all horses consisted of stall rest for 60 to 90 days. In addition, 2 horses were administered sodium hyaluronate intra-articularly, 1 horse was given injections of polysulfated glycosaminoglycans IM, and 1 horse was given phenylbutazone orally. Follow-up information was compiled 6 weeks to 4 years after initial examination. At the time of follow-up inquiry, 6 horses were sound for intended use and only 1 horse became lame when exercised. A logical approach to choice of surgical or nonsurgical treatment is proposed on the basis of these findings and those reported in the literature.     

Subchondral osseous cystic lesions of the elbow of horses: conservative versus surgical treatment

Subchondral osseous cystic lesion of the elbow was diagnosed as a cause of lameness in 6 horses. Persistent lameness and signs of degenerative joint disease developed in the first 3 horses treated conservatively with confinement. Subsequently, 3 horses were each treated by extra-articular enucleation of the cystic cavity via the proximal-medial aspect of the radius. Compared with conservative management, better long-term success (determined by return of athletic soundness and less evidence of degenerative joint disease) was achieved with surgical curettage of elbow subchondral cystic lesions.     

Clinical and low field magnetic resonance imaging features of osseous cyst‐like lesions of the proximal sesamoid bones in seven horses

Osseous cyst‐like lesions of the proximal sesamoid bones (PSBs) were diagnosed in 7 horses. The diagnosis was achieved radiographically prior to magnetic resonance imaging (MRI) in only one horse, and in the other 6 horses the diagnosis was made using low field MRI (retrospective evaluation of the radiographs after the MRI revealed ill‐defined radiolucencies of the PSBs in 4 of these horses). The horses ranged in age from 3 to 12 years, and the affected limbs included 3 forelimbs and 4 hindlimbs. The onset of lameness was reported to be sudden in 6 horses and insidious in one, and the duration of lameness at the time of MRI ranged from 0.3 to 11 months. The degree of lameness in the 6 horses with sudden‐onset lameness was moderate to severe. Pain on flexion of the affected metacarpo(tarso)phalangeal (fetlock) joint or exacerbation of the degree of lameness following fetlock flexion was recorded in 4 of the 7 horses. The MRI findings in all cases included a focal high signal intensity lesion (all magnetic resonance sequences) at various locations in one PSB. Both septic and nonseptic aetiologies were identified. Four of the 7 horses were subjected to euthanasia due to persistent lameness, one remained chronically lame and only 2 were able to return to their previous level of exercise.     

Treatment of mandibular first molar teeth with endodontic-periodontal lesions in a dog

A two-year-old spayed/female Miniature Pinscher was treated for mobility of the left and right mandibular first molar teeth. Periodontal probing and intraoral dental radiographs indicated severe periodontal attachment loss. It was determined that both teeth had endodontic-periodontal lesions based on restoration of periodontal attachment and partial resolution of radiolucent periapical lesions following treatment which emphasized endodontic therapy.     

Primary osseous melanoma in the tibia of a dog

An 18-month-old, female Cane Corso dog was presented with a suspected primary tumor of the tibia. Plain radiographs and computed tomography (CT) of the tibia were highly suggestive of a primary bone neoplasm. A diagnosis of malignant melanoma was made by cytology. Total body survey radiographs, CT scan of the thorax, and abdominal ultrasound excluded the presence of neoplastic lesions other than in the tibia. Limb amputation was performed. Histology and immunohistochemical analysis of the tibial neoplasm confirmed the diagnosis of a melanoma with secondary metastasis to the popliteal lymph node. The dog was alive and in good physical condition 43 months after surgery.     

Colonic adenocarcinoma with osseous metaplasia in a horse

Rectal palpation of a 30-year-old mixed-breed mare with chronic weight loss and intermittent, refractory abdominal pain revealed a mass in the right caudoventral portion of the abdomen. Hematologic and serum biochemical findings were normal except for slight mature neutrophilia and mildly high alkaline phosphatase activity and total bilirubin concentration. Cytologic examination of a specimen obtained by abdominocentesis revealed equal numbers of nondegenerative neutrophils and macrophages, but no evidence of neoplastic cells. The mare continued to have signs of abdominal discomfort and was euthanatized. Necropsy revealed a large mass at the junction of the right dorsal colon and transverse colon, and several smaller masses in the liver. Histologic characteristics of the small-colon mass were consistent with colonic adenocarcinoma with osseous metaplasia.     

Prostatic adenocarcinoma with osseous metastases in a dog

Bone scintigraphy was used to diagnose osseous metastasis of prostatic adenocarcinoma in a 10-year-old dog with neck pain and ataxia and a large, sensitive prostate gland. Although radiography revealed a normal spine, prostatic fluid cytologic and ultrasonographic findings were compatible with prostatitis or neoplasia. Scintigraphic hot spots were seen in the axial skeleton, ribs, pelvis, humerus, and femur and corresponded to sites of metastatic prostatic adenocarcinoma.     

Wounds associated with osseous sequestration and penetrating foreign bodies

Nonhealing wounds can present a frustrating clinical challenge to the veterinary practitioner. In many cases, healing is delayed by the presence of a foreign body or sequestrum; a review of wounds complicated by the presence of osseous sequestration and penetrating foreign bodies is presented. The typical signs include delayed wound healing and the presence of serous to exudative drainage, which may vary from intermittent to continuous. The use of radiographic or sonographic imaging modalities is often of value in reaching a diagnosis. Removal of the sequestra or foreign body is generally curative.     

Multiple osseous metastases of a carotid body tumor in a dog

Metastasis of malignant carotid body tumor to multiple bones was detected in a 13-year-old female Siberian husky dog. Radiographs exhibited an abnormal mass in the retropharyngeal site and osteolytic lesions in the vertebral bodies, spinous process, tibia, and ribs. At necropsy, multiple masses were observed in the bones as well as at the dorsal area of the retropharynx. Histologically, the tumor cells, arranged in sheets and clusters, had eosinophilic finely granular cytoplasm. Immunohistochemistry showed the tumor cells were positive for neuron-specific enolase and synaptophysin. Electron microscopy demonstrated a number of dense membrane-bound granules in the cytoplasm of the tumor cells. Based on these findings, this case was diagnosed as multiple bone metastases of a malignant carotid body tumor. Spinal cord damage induced by the tumor mass was the cause of the hind limb paralysis of the present dog.     

Idiopathic osseous hyperplasia of the nasal turbinates in a Welsh terrier

A three-year-old Welsh terrier was presented with a 6-month history of progressive stertor, exercise intolerance and sneezing which was unresponsive to symptomatic treatment. A large calcified mass occupying the entire rostral right nasal cavity was defined with computed tomography. The mass was completely removed via a dorsal rhinotomy. Histopathological examination of the mass revealed osseous hyperplasia of the nasal turbinates. The excision led to complete resolution of clinical signs and there has been no recurrence 18 months after surgery.