Excisional biopsy and radiotherapy for management of an olfactory neuroblastoma in an axolotl (Ambystoma mexicanum)

Abstract

CASE DESCRIPTION A 4-year-old sexually intact male leucistic axolotl (Ambystoma mexicanum) was presented with a 2-week history of dysrexia and difficulty swallowing. CLINICAL FINDINGS Physical examination revealed a 1-cm-diameter intraoral mass on the rostral aspect of the palate and swelling of the left nasal fossa. Local invasion into the left nasal fossa was suspected during oral examination. The lesion was marginally excised, and an incompletely excised olfactory neuroblastoma was diagnosed histologically. Five weeks later, physical examination revealed persistent erythema, delayed healing of the rostral portion of the palate, and a mild facial deformity associated with a white mass in the nasal cavity. TREATMENT AND OUTCOME 6 weeks after excision, adjuvant electron (6-MeV) beam radiotherapy was initiated for treatment of the incompletely excised olfactory neuroblastoma and likely presence of a recurrent mass. The protocol consisted of 4 weekly fractions of 8 Gy each (total, 32 Gy) with the axolotl under anesthesia. No acute adverse radiation effects were noted following radiotherapy. The oral erythema resolved after the third session. No recurrence was observed 2 months after treatment, and the owners reported no abnormal signs at home. The axolotl died 3.5 months after radiotherapy was completed (8 months after marginal excision of the tumor) secondary to an environmental management failure. Postmortem histologic evaluation showed no evidence of neoplasia. CLINICAL RELEVANCE In axolotls, olfactory neuroblastoma should be considered in the differential diagnosis of intraoral palatal masses. This report describes the first application of radiotherapy for treatment of an olfactory neuroblastoma in an axolotl.

Axolotl: A resourceful vertebrate model for regeneration and beyond

“…Despite the cancer resistance, up to date, there have been few cases reported in axolotl associated with carcinoma. In 1980, melanophoromas were detected in the skin samples of 2 axolotl, 117 cutaneous mastocytomas have been reported in 18 axolotls aged about 11–17 years, 118 and olfactory neuroblastoma cases were observed 119 and even treated with radiotherapy 120 . Furthermore, it has been shown that axolotl oocyte extracts (AOE) are able to reprogram breast cancer cells via DNA demethylation, re‐activation of silenced tumor suppressors expressions, removal of repressive histone marks on tumors suppressors' promoters, reduction of cancer cell and tumor growth in mouse xenografts 121 (Figure 4).…”

Gross and Ultrasonographic Anatomy of the Coelomic Organs of Healthy Axolotls (Ambystoma Mexicanum)

“…11,12,23 Axolotls can be affected by a variety of diseases, including gastrointestinal (e.g., foreign bodies, constipation, duodenal mucosal hyperplasia, gastric prolapse), urogenital (e.g., testicular tumor, perivesical abscess), and cardiac conditions (e.g., necrotizing myocarditis), as well as neoplasia and buoyancy disorders. 10,19,22,26,28,29,36,38 – 40 All of these pathologies could be diagnosed using ultrasonographic examination, knowing the aspect of healthy coelomic organs. Axolotls are studied for their regenerative abilities, but diagnostic imaging of their anatomy remains poorly described.…”