Radiation and Intralesional Chemotherapy for a Fibrosarcoma in a Boa Constrictor, Boa constrictor ortoni

Abstract

A 10-yr-old. female, boa constrictor, Boa constrictor ortoni. with a malignant subcutaneous fibrosarcoma of the body wall was treated with surgery and adjunctive radiation therapy. A total dose of 48 Gy was delivered in 16 equivalent 3 Gy fractions by a cobalt radiation unit over a 21 d period. The mass enlarged over the course of radiation therapy and a post radiation complete blood count revealed thai the animal had 3 developed a leukopenia (WBC 2.7 x 10 cells/ul) with severe lymphopenia (0 cells/ul). Additional chemother- apy consisting of 50 mg of intralesional carboplatin was administered following radiation. Surgical biopsies taken at that time revealed a marked decrease in malignant fibrosarcoma cells when compared to the histopathology prior to radiation. However, a severe granulomatous cellulitis with intralesional acid-fast bacil- l i was also present. Numerous colonies of Mycobacterium chelonei were cultured from the body wall and subcutaneous tissue at the tumor site. The animal was euthanized and postmortem examination revealed only rare foci of neoplastic fibroblasts. Although, this fibrosarcoma appeared to be histologically radioresponsive, the snake developed marked myelosuppression. and infection with Mycobacterium chelonei.