Reinke's crystals in an interstitial cell tumour of a rabbit (Oryctolagus cuniculus)

Sertoli cell tumour in a pet rabbit (Oryctolagus cuniculus): histological and immunohistochemical characterization

The present study describes a case of a spontaneous, unilateral Sertoli cell tumour (SCT) in a 6-year-old pet rabbit. The rabbit was presented with a palpable, unilateral, subcutaneous left inguinal mass, consistent with the suspected clinical diagnosis of neoplasia developing within the retained testis in the inguinal canal. The intrascrotal contralateral testis was palpable, but reduced in volume. The rabbit underwent orchiectomy and both the testes were collected, formalin-fixed, and submitted for histopathological examination. Microscopically, the enlarged testis was effaced by an intratubular SCT in which numerous intratubular microliths were evident. The contralateral testis was severely atrophied. Immunohistochemical stains showed neoplastic Sertoli cells that were diffusely positive for vimentin and anti-Müllerian-Hormone and multifocally positive for cytokeratins and desmin. Eighteen months after the surgery, the rabbit showed no clinical signs of disease. This is the first report of a spontaneously occurring rabbit SCT histologically described and immunohistochemically investigated.

Disorders of the Reproductive Tract of Rabbits

Disorders of the reproductive tract are common in rabbits. Conditions are different in rabbits that are farmed for their meat or fur and those that are kept as pets. Farmed rabbits suffer from infections and diseases associated with pregnancy. Congenital abnormalities are more likely to be recognized and treated in pet rabbits. Pet rabbits suffer from age-related changes to their genital tract (hyperplasia, neoplasia, or hernias). Neutering is an important part of prevention and treatment of reproductive disorders. Knowledge of normal male and female reproductive anatomy is essential to prevent complications. These are described and illustrated.

Testicular Interstitial Cell Tumor and Gynecomastia in a Rabbit

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.

Visualization of Reinke's crystals in normal and cryptorchid testis

Within the human testis, Reinke's crystals are found in Leydig cells but their nature and function are poorly understood. The aim of our study was to investigate the properties of Reinke's crystals in man with the normal morphology of the testis (control group) and infertile patients diagnosed with cryptorchidism. 20 biopsies from infertile patients and six biopsies from men with regular spermatogenesis (20-30 years.) were used. Sections of the testis tissue were stained with haematoxylin and eosin and a modified Masson's method. Specimens were observed by bright field, confocal and transmission electron microscopy (TEM). The number of Reinke's crystals in investigated groups was determined applying stereological methods. In both groups, Reinke's crystals were noted within the cytoplasm and nuclei of Leydig cells. Some "free" crystals were found within the interstitial space, outside Leydig cells. Confocal microscopy proved to be very useful in the assessment of the shape and 3D reconstruction of the crystal. TEM analysis confirmed a hexagonal form of the crystal, while crystallographic data on sections of 70-300 nm thickness provided a better insight into the organization of the crystal lattice. Stereological analysis revealed a significant increase in the number of crystals in cryptorchid testes when compared with controls. Increased number of crystals in cryptorchid specimens leads to the assumption that the prolonged exposure to higher (abdominal) temperature might stimulate enzymes involved in the synthesis of the proteins of the crystal. However, the exact molecular nature of the crystal lattice remains in both normal and cryptorchid testis obscure.

Granular Cell Tumor in the Testis of a Rabbit: Cytologic, Histologic, Immunohistochemical, and Electron Microscopic Characterization

An adult pet rabbit ( Oryctolagus cuniculus) presented with a progressively enlarging left testicle. Because neoplasia was suspected, the testicle was removed. Pathologic evaluation (exfoliative cytology, histopathology, immunohistochemistry, electron microscopy) indicated that the tumor was an intratesticular granular cell tumor. Granular cell tumor has not been described in rabbits before and has not been described in the testes of animals or postnatal humans. Granular cell tumor should be included as a differential diagnosis of testicular tumors, particularly Leydig cell tumor, because of potential histologic similarities.