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Testicular interstitial cell tumor and gynecomastia in a rabbit
K A Maratea1, J A Ramos-Vara, L A Corriveau
1Animal Disease Diagnostic Laboratory, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA. maratea@purdue.edu
Insights
This study reports the first concurrent diagnosis of a testicular interstitial (Leydig) cell tumor and gynecomastia in a rabbit. These findings highlight novel endocrine and reproductive health conditions in rabbits.
Area of Science:
- Veterinary Pathology
- Endocrinology
- Reproductive Biology
Background:
- Testicular interstitial (Leydig) cell tumors are rare in rabbits.
- Gynecomastia, or abnormal mammary gland development in males, has not been previously reported in rabbits.
Observation:
- An adult male rabbit presented with a unilateral testicular interstitial cell tumor and multiple subcutaneous masses.
- Histopathological examination revealed a Leydig cell tumor and hyperplastic mammary gland tissue with pseudolactational changes.
- Immunohistochemistry confirmed neoplastic interstitial cells (Melan A+) and hyperplastic mammary epithelium (progesterone receptor+, p63+).
Findings:
- Concurrent occurrence of interstitial cell tumor and gynecomastia in a rabbit.
- Identification of Melan A as a marker for neoplastic Leydig cells in rabbits.
- Characterization of hyperplastic mammary tissue and hormonal receptor expression in rabbit gynecomastia.
Implications:
- Establishes a precedent for concurrent Leydig cell tumors and gynecomastia in rabbits.
- Provides insights into steroid hormone-related pathologies in male rabbits.
- Suggests potential for similar endocrine disruptions in rabbit populations.
Abstract:
Unilateral testicular interstitial (Leydig) cell tumor and gynecomastia were diagnosed in an adult male rabbit. The interstitial cell tumor was a well-circumscribed, 2-mm diameter, pale tan nodule composed of a uniform population of polygonal cells. Neoplastic interstitial cells exhibited diffuse, granular cytoplasmic staining with Melan A, a marker of steroid-producing cells in humans and dogs. Multiple subcutaneous masses in the caudal abdomen were associated with enlarged nipples and consisted of hyperplastic mammary gland tissue with proliferation of ducts and alveoli, marked lobule formation, and pseudolactational hyperplasia. Many epithelial cells lining the hyperplastic ducts and alveoli exhibited intense nuclear expression of progesterone receptor antigen, whereas myoepithelial cells showed strong nuclear staining for p63 antigen. This is the first report of concurrent interstitial cell tumor and gynecomastia in a rabbit and also the first description of gynecomastia in this species.
