Lymphoma in an alpaca
Keywords: alpaca, camelid, lymphoma
With thanks to Dr Andrea Bourque DVM ACVP for the pathology contribution to this description.
The uterus of a 16 year old alpaca in moderate to poor body condition was submitted for pregnancy diagnosis. Her body weight was 82Kg. Feed intake could not be accurately determined but the animal was reported to lag behind others when the herd was called for feeding. Otherwise, she was bright, alert and responsive and able to rise and ambulate normally. The owners believed that she may be pregnant because a male had been with the herd for an extended period of time.
On transabdominal and transrectal ultrasonic examination, no pregnancy was visible. Instead, large highly echogenic masses were seen to surround the uterus and adnexa. Vacuolated, fluid-filled non-echogenic areas were present within the masses. These are shown here:
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In one cross-section of one of the uterine horns, a solid and vacuolated mass appeared to impinged on the lumen (outlined below). Indeed. later post mortem examination showed this to be case.
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Due to the absence of pregnancy, a strong possibility of neoplasia and the advanced age of the animal, she was euthanized and submitted for postmortem examination. The images below show masses of what appeared to be lymphoma-like tissue in the myometrium and uterine adnexa. The ovaries were not affected. Note the thick mass of tissue being incised; contiguous with, and adjacent to the left uterine horn.
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There was also a large retroperitoneal mass which surrounded (but did not invade) the kidneys and adrenal glands and extended caudally to the pelvic inlet. It is shown below
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This locally invasive tumor also invaded and markedly expanded the wall of a large segment of distal colon and much of the reproductive tract extending from the mid vagina, encompassing the cervix, uterine body and adjacent uterine horns (sparing the terminal portions of the horns). Otherwise, neoplastic infiltrates were not seen elsewhere. This distribution was supported by histopathology.
The microscopic features of this tumor are shown below.
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Small foci of lytic necrosis and hemorrhage were scattered within the mass. The tumor cells had large round to oval to sometimes reniform nuclei with variably prominent nucleoli, coarsely stippled chromatin, and small amounts of poorly defined, pink-grey, cytoplasm. Anisokaryosis (yellow arrows) was moderate. Mitotic figures (black arrows) were present in very high numbers (approximately 160 in 10 HPF). Occasional binucleate cells were also noted.
