Treatment of an amelanotic melanoma using radiation therapy in a lesser Madagascar hedgehog tenrec (Echinops telfairi).
A 15-yr-old, male lesser Madagascar hedgehog tenrec (Echinops telfairi) presented with a mass caudal to the right ear. Cytology suggested a sarcoma. Surgical removal was attempted. Histology was consistent with a soft tissue sarcoma. The mass recurred within 331 days post operation. Radiation therapy was initiated. Computed tomography was used for staging in conjunction with three-dimensional computerized treatment planning software to permit accurate lesion localization and to optimize normal tissue sparing. A total dose of 6,480 cGy was administered in 24 fractions over 46 days. Transient hind limb paresis developed during the course of the radiation therapy, but resolved after 7 days with prednisone treatment. Minimal acute radiation toxicity was observed. The mass responded with at least a 90% reduction in volume following radiation treatment. The animal survived 266 days from the initiation of treatment. On necropsy, a small mass and granulation tissue were found at the site of the initial neoplasm, indicating good regional control of the tumor; however, extensive metastases to the spleen and liver were present. Immunohistochemically, the original, recurrent, and metastatic populations were strongly positive for HMB 45 and weakly positive for S-100, and the final diagnosis was metastatic amelanotic melanoma.
Harrison
Tara M
TM
Potter Park Zoo, 1301 South Pennsylvania, Lansing, Michigan 48912, USA. taramharrison@gmail.com
Dominguez
Pedro
P
Hanzlik
Kim
K
Sikarskie
James G
JG
Agnew
Dalen
D
Bergin
Ingrid
I
Fitzgerald
Scott D
SD
Kitchell
Barbara E
BE
McNiel
Elizabeth
E
D000818:Animals; D007312:Eulipotyphla; D017809:Fatal Outcome; D008297:Male; D018328:Melanoma, Amelanotic / Q000532:radiotherapy / Q000601:surgery / Q000662:veterinary*; D011878:Radiotherapy / Q000009:adverse effects / Q000662:veterinary