Palliative care of a large captive saltwater crocodile ( Crocodylus porosus ) with metastatic digital squamous cell carcinoma

A 4.90 m male saltwater crocodile, "Burt", was first noticed with irregular keratinisation involving the claw of the first digit of his left hind limb in December 2021. Three months later (March 2022), the digit had significantly increased in size and was noticeably affecting his weight-bearing ability. An excisional biopsy was performed, involving digit amputation. Histopathology revealed that the lesion was a squamous cell carcinoma (SCC), complicated by ulceration and opportunistic Morganella morganii infection. Within 3 months, the mass recurred. In June 2022, a second amputation was performed, this time through the distal femur. Histology revealed that although clusters of neoplastic cells were present within lymphatics near the main mass, the amputated margins were clear of SCC. After both interventions, the crocodile resumed eating and behaving normally within 24 h, although after the second surgery he was observed to have some balancing issues as he readjusted to the missing limb. In June 2024, the crocodile's food consumption declined; he lost interest in interacting with the keepers, displayed strong food preferences that changed frequently and generally became less responsive and active. Despite no local reoccurrence of the mass 2.5 years post-surgery, the crocodile succumbed to metastasis in the heart and liver, causing cardiac failure and terminal drowning. This study provides insights into the progression of digital SCC and a discussion of the palliative care options that are available for large crocodilians.