Xanthophoroma in a Striped Burrfish, Chilomycterus schoepfi

Area of Science:

• Aquatic veterinary medicine
• Comparative oncology
• Ichthyology

Background:

• Neoplasia is a significant concern in captive aquatic species.
• Chromatophoromas are common skin tumors in fish, but specific subtypes can be rare.

Purpose of the Study:

• To diagnose and characterize a dorsal head mass in a striped burrfish.
• To investigate the nature of a recurrent neoplasm in an aquarium fish.

Main Methods:

• Surgical excision and cryosurgical ablation of the mass.
• Histopathologic and ultrastructural evaluation of tumor tissues.
• Immunohistochemistry and pigment analysis (absorbance spectrophotometry, gas chromatography-mass spectrophotometry).

Main Results:

• Recurrent exophytic yellow-orange mass on the dorsal head.
• Histopathology suggested chromatophoroma; immunohistochemistry was negative for SOX10, Melan-A, and PNL-2.
• Ultrastructural analysis revealed features consistent with xanthophoroma, erythrophoroma, or mixed xanthoerythrophroma.
• Pigment analysis identified xanthopterin as the primary pigment, confirming xanthophoroma.

Conclusions:

• The fish presented with a rare xanthophoroma, a subtype of chromatophoroma.
• Recurrence after surgical and cryosurgical treatment highlights the aggressive nature of the tumor.
• Accurate diagnosis required a combination of histopathology, ultrastructural, and pigment analysis.