Signs of Sympathetic Denervation Associated With a Thoracic Melanoma in a Horse

Abstract

Sympathetic denervation in a 20-year-old, gray, Thoroughbred-Percheron gelding was manifested by cutaneous hyperthermia and sweating over the right side of the body, demarcated by a line from the withers to the elbow and extending cranially. There was cutaneous hyperthermia over the right side of the head, but other signs of Horner's syndrome (sweating, ptosis, miosis, enophthalmos) were not present. The pattern of cutaneous hyperthermia and sweating was consistent with sympathetic denervation localized to the cervicothoracic ganglion, and thoracic radiographs 20-year-old, gray, Thoroughbred-Percheron gelding A was examined because of increased heat in the distal right front limb but no associated lameness. The owner also reported that the right front hoof had grown more than the left front hoof during the previous month. The horse had been examined frequently at the hospital during the previous 3 years for a chronic gastric ulcer problem, and this new problem had never been reported to or noted by the attending clinician. The horse was maintained in a 4-acre field with 2 other horses and was used for occasional light riding.Examination revealed the horse to be bright and in good body condition. Temperature, pulse rate, and respiratory rate were within normal limits. The skin over the right front limb from the carpus down felt warmer than the skin over the left front limb. Also the skin over the right side ofthe neck felt slightly warmer than that on the left side. There was no evidence of pain with hoof testers, on flexion of the front limbs, or at a trot. Radiographs of the distal right front limb had been taken by the referring veterinarian and no lesions had been detected.Nuclear scintigraphy was performed to determine whether there was an underlying lesion in the distal right front limb that might coincide with the increased skin temperature. Scintigraphy was performed using 200 mCi technetium 99m monodiphosphonate. Soft tissue phase imaging was performed 10 minutes after administration of the radiopharmaceutical, and bone phase imaging was performed 180 minutes after its administration. The soft tissue phase imaging revealed moderate, focal uptake of radiopharmaceutical over the palmar aspect of the right coronary band, compared to the left limb. The bone-phase imaging revealed diffuse increased uptake in both front third phalangeal bones, with greater uptake in the right front compared to the left front third phalanx. These findings were nonspecific and were not interpreted to be associated with the increased skin temperature over the right front limb.The next week the owner indicated that the horse had developed a sinall focal area of intermittent sweating over the right scapula. This occurred in February, and sweating was not visible over any other area of the horse. A neurologic examination was performed and no abnormalities were noted. Another lameness evaluation revealed mild sensitivity to palpation of both front iuspensory ligaments, and ultraso- nography revealed a mild lesion in the right front s...

A Comparative Review of Melanocytic Neoplasms

“…8,92,150 More atypical sites have been reported, such as the coronary band, 130 foot, 110 vertebral region, 124,198 and pelvic canal. 124 Rarely, the thoracic cavity, 167,225 nasal cavity, 62 and eye 14,56,67,149 have been involved. Clinical signs range from interference with bridle, bits, and saddle to more serious obstructive lesions in the urogenital or gastrointestinal tract, progressing to life-threatening pulmonary or visceral metastasis.…”

“…212 Other more unusual manifestations include Horner's syndrome and unilateral sweating. 157,167 Equine metanocytic neoplasms have traditionally been grouped according to one of the three growth patterns. Some grow slowly over many years without metastasizing, whereas others grow slowly initially, with a subsequent increase in the rate of growth after a few years.…”

Aetiology, clinical presentation and current treatment options of equine malignant melanoma – a review of the literature

“…Visceral metastases can occur not only in parenchymal organs (Figure 2), bone-marrow and mesentery, but also in skeletal muscle (Rodriguez et al 1998, Patterson-Kane et al 2001, Macgillivray et al 2002, Kovac 2005, Garvican et al 2007. Masses may compress the peripheral nerves (Murray et al 1997) or the spinal cord and, therefore, lead to neurologic deficits (Patterson-Kane et al 2001, Rosengren Pielberg et al 2008. Moore et al (2013) proposed a clinical classification into four progressing stages in which horses showing only a single melanoma with a diameter of less than 2 cm and a slow growth is classified as stage 1.…”

Aortic valve insufficiency and myocardial melanoma in a horse

“…Metastasen entstehen in der Regel zuerst in den regionalen Lymphknoten. Von hier breitet sich der Tumor meist auf die serösen Häute, sowie in Lunge, Leber, Milz und in das Rückenmark weiter aus (Mair und Brown 1993, Murray et al 1996, Rodriguez et al 1998Mac Gillivray et al 2002 …”