Case Study

Primary brachial plexus soft tissue osteosarcoma with liver metastasis in a 11 year old MN Welsh Corgi dog

An 11-year-old MN Welsh Corgi dog with history of elevated liver enzyme activity (treated with Denamarin for three weeks), a nerve sheath tumor in right axilla that had been diagnosed on MRI, and more recently had developed an open hygroma on the left elbow, was presented for recheck blood work. Current therapy was gabapentin, steroids, pain medication, cephalexin, doxycycline, gastroprotectants, and vitamin K. CBC showed mild anemia, thrombocytosis, monocytosis.

An 11-year-old MN Welsh Corgi dog with history of elevated liver enzyme activity (treated with Denamarin for three weeks), a nerve sheath tumor in right axilla that had been diagnosed on MRI, and more recently had developed an open hygroma on the left elbow, was presented for recheck blood work. Current therapy was gabapentin, steroids, pain medication, cephalexin, doxycycline, gastroprotectants, and vitamin K. CBC showed mild anemia, thrombocytosis, monocytosis. On blood chemistry markedly elevated ALP activity, elevated ALT and GGT activity, hypocalcemia, high BUN/creatinine ratio, and hyperlipasemia was evident.

DX

Compound osteosarcoma of soft tissue of the brachial plexus with liver metastasis.

Sonographic Differential Diagnosis

Multiple mineralizing hepatic target type lesions suggestive for metastatic disease, possible nodular hyperplasia or embolic disease. Concurrent cholangitis or cholangiohepatitis. Guarded to poor long term prognosis.

Image Interpretation

The liver presented multiple mildly hypoechoic nodular changes with multifocal hyperechoic foci consistent with potential metastatic disease given the axillary tumor. This is most likely metastatic sarcoma or similar neoplastic event. Concurrent cholecystitis is present with edematous and thickened gallbladder and some debris. The remainder of the liver presented swollen contour and increased echogenic portal markings consistent with cholangiohepatitis.

Outcome

A few days later the patient presented at an emergency hospital with bruising on the abdomen. On physical examination there were ecchymotic hemorrhages over the entire ventral abdomen extending up to the right axilla; tetraparesis associated with right front limb lameness with decreased postural reactions and reflexes; and mild hyperpathia upon manipulation of the cervical spinal column. PCV/TP was stable between 26-28%, 4DX test was negative, abdominal ultrasound showed no evidence of active bleeding, and thoracic radiographs were negative for effusion and metastatic disease. Follow up physical examination several days later was predominantly unchanged, although the ecchymotic hemorrhages were resolving. The current medications were continued. Three days later the patient was presented on emergency with lethargy, weakness, distended abdomen, and tachypnea. On physical examination the patient was lethargic, weak, tachypneic, tachycardic, non-ambulatory on front right forelimb and there were new ecchymoses on the left caudoventral abdomen. Mucous membranes and heart and lungs were all normal. PCV/TP was 17/5.2. The patient was treated with Benadryl and was transfused with packed red blood cells and fresh frozen plasma. The following day patient was QAR, eating well, and eupneic. Due to poor prognosis and no hope of improvement of quality of life, owner’s elected to euthanize. On postmortem a primary compound osteosarcoma of soft tissue of the brachial plexus with liver metastasis was diagnosed.

Comments

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Clinical Differential Diagnosis

Liver pathology: acute drug induced, neoplasia, infectious, Cushing’s disease, toxin; GI blood loss

Sampling

US-guided FNA cytology from the brachial plexus mass had a low diagnostic yield – blood and rare spindle cells. Liver aspirates showed multifocal to diffuse, moderate to marked, hepatocellular degeneration and moderate bile stasis and was concurrent with neutrophilic inflammation.