Presumed hemocytic neoplasms in scorpions

Area of Science:

• Invertebrate pathology
• Arachnid oncology
• Comparative oncology

Background:

• Neoplasia is documented in invertebrates but not previously reported in scorpions.
• Scorpions are arachnids with a unique physiology and immune system.

Purpose of the Study:

• To describe presumed hemocytic neoplasia in two scorpion species.
• To characterize the histological features of these neoplastic masses.
• To contribute to the understanding of neoplasia in arachnids.

Main Methods:

• Necropsy and histological examination of two affected scorpions: an emperor scorpion (Pandinus imperator) and an Asian forest scorpion (Heterometrus sp.).
• Detailed microscopic analysis of neoplastic masses, including cellular morphology and mitotic activity.
• Assessment for signs of inflammation such as melanization and nodulation.

Main Results:

• Presumed hemocytic neoplasia was identified in both scorpions.
• Emperor scorpion: a white mass in the caudal coelom associated with body wall swelling.
• Asian forest scorpion: multiple coelomic masses invading skeletal muscle. Histologically, masses showed sheets of hemocytes with specific cytologic features and low mitotic rates, lacking signs of inflammation.

Conclusions:

• The masses were diagnosed as a hemocytoma in the emperor scorpion and a hemocytic sarcoma in the Asian forest scorpion.
• These findings represent the first report of neoplasia in scorpions, possibly originating from plasmatocytes.
• Further research is needed to understand the etiology and prevalence of neoplasia in scorpions.