Because of the dog's persistent seizure activity, we discontinued the phenobarbital and initiated potassium bromide therapy
at a loading dosage of 125 mg/kg given orally twice a day for five days, followed by a maintenance dosage of 20 mg/kg given
orally twice a day. We performed an exploratory laparotomy the day after presentation and identified four hepatic nodules:
a 4-cm nodule on the left medial lobe, a 4-cm nodule on the left lateral lobe, a 6-cm nodule on the right medial lobe, and
a 1-cm nodule on the quadrate lobe. We removed the nodules on the left lateral and medial lobes with a TA 55 surgical stapler
(Tyco Healthcare), the nodule on the quadrate lobe by using a ligation technique, and the entire right medial lobe with a
TA 90 surgical stapler (Tyco Healthcare). We submitted all samples for histologic examination.
The dog received routine postoperative care and recovered without complication. The dog continued receiving the potassium
bromide and phenylpropanolamine at the previously described dosages. The histologic examination results were consistent with
multifocal ectopic splenic tissue within the liver in each sample (Figure 1). No abnormalities were found at a recheck examination two weeks after surgery.
Figure 1. A photomicrograph of a section of ectopic splenic tissue in the liver from the dog in this case. Fibrous tissue
(arrow) containing some hemosiderin-laden histiocytes separates the splenic tissue from hepatic tissue (hematoxylin-eosin
stain; bar = 150 µm).
On a follow-up examination seven months after the liver lobectomy, the owner reported that the dog was more alert and active
and that seizures were rare. On a routine follow-up abdominal ultrasonographic examination, we noted complex cavitary infiltrates
associated with the left lateral and medial liver lobes. We obtained a fine-needle aspirate of one of the cavitary infiltrates
and submitted it for cytologic examination. The smears consisted of a thick layer of blood with occasional macrophages, rare
hemosiderin, and no hepatocytes. These findings were consistent with hemorrhagic fluid. No definitive diagnosis could be made.
We recommended a liver biopsy, but the owner declined further testing. The owner agreed to make arrangements for follow-up
examinations and abdominal ultrasonographic examinations every three or four months to monitor for changes.
One month later, the dog was presented for evaluation of lethargy and anorexia of one day's duration. The dog's packed cell
volume was 22%. The owner declined diagnostic tests, and we admitted the dog for observation. Two days later, we discharged
the dog because of an improved attitude and appetite and a packed cell volume of 28%. In subsequent phone conversations over
several months, the owner has reported that the dog has had intermittent lethargy. Further packed cell volumes performed by
the referring veterinarian have been 24% to 26%. The referring veterinarian instituted vitamin E (400 IU/day) as antioxidant
Ectopic splenic tissue is defined as microscopically normal splenic tissue in an abnormal location.1,2 Intrahepatic splenic tissue is rarely diagnosed in people and veterinary patients. It has only been reported in four people,1,3 one pig,4 and one dog.5 In other cases, ectopic splenic tissue has been found in the pancreas, kidneys, ovaries, uterus, scrotum, abdominal wall,
lungs, and pericardium.2,3,6,7
All of the reported cases of intrahepatic splenic tissue in people and in the dog occurred after splenectomy, while the pig
had a normal spleen at time of diagnosis.1,3,4 In people, intrahepatic splenic tissue was found either postmortem or as an incidental finding.1,3 But in the dog, there was a history of acute lethargy and abdominal pain. The diagnosis of intrahepatic splenic tissue was
made postmortem.5 Another important difference among these cases was that in three of the people, both dogs, and the pig, fibrous tissue separated
the splenic tissue from the hepatic tissue1,3,4,8; in the other person,3 the hepatic and splenic tissues abutted directly. These histologic differences may reflect different causes of ectopic splenic
tissue in the liver.