Sex cord stromal tumor of the cat: so-called androblastoma with Sertoli-Leydig cell pattern

Folliculogenesis in the domestic cat (Felis catus)

The dynamic regulation of mammalian folliculogenesis is a key component of the reproductive process. Traditionally, the rodent had been used as a model to study ovarian function and reproductive physiology due to the availability of animals, their relatively short cycle length, high rate of fecundity and short generation interval. We maintain that much basic information can be determined using domestic cat ovaries retrieved from local veterinary clinics following routine spaying, without having the expense of maintaining a colony of laboratory cats. Studies of normal feline reproductive physiology and advances in reproductive technology may be extrapolated for use in endangered non-domestic felids. Increased understanding of feline reproduction will be beneficial to veterinary medicine, and to groups working to control feral cat populations. It is important to examine reproductive mechanisms in alternative animal models as there are a vast number of threatened and endangered species in which we lack the critical reproductive information needed to assist in preserving their long-term survival.

Reproductive oncology

The actual incidence of reproductive tract tumors is difficult to ascertain, presumably because a significant percentage of dogs and cats are neutered, particularly in the United States. Data from European countries, where elective neutering is less common, provides insights. Several studies document the relative frequency of reproductive tumors. Larger studies of the more common tumors, e.g., testicular tumors, provide a substantial amount of information on the clinical presentation and response to treatment of dogs, but overall there is less information available on cats. Numerous case reports document the less commonly reported tumors and will be included in the following discussion.

Morphology of canine ovarian Sertoli-Leydig cell neoplasms. A report of 12 cases

Of 71 dogs with primary ovarian neoplasms, 12 (17%) had Sertoli-Leydig cell tumors. Five dogs had Sertoli-Leydig cell tumors, four had pure Sertoli cell tumors, and three had Sertoli-Leydig cell tumors with a retiform pattern. Variously differentiated Sertoli cells were seen in the Sertoli-Leydig cell tumors, and one of these metastasized to the peritoneum. The pure Sertoli cell tumors were similar to these tumors in male dogs. The retiform pattern in the third group of tumors was characterized by tubuloalveolar structures resembling rete testes. Heterologous elements were seen in seven tumors (58%)--enteric glands in three Sertoli-Leydig cell tumors and one Sertoli-Leydig cell tumor with retiform pattern, and neuroendocrine carcinoma in one pure Sertoli cell tumor and two Sertoli-Leydig cell tumors with retiform pattern. The uterus was examined in seven dogs, and six (87%) had endometrial hyperplasia.

Testicular (Sertoli's cell)-like tumors of the ovary induced by N-ethyl-N-nitrosourea (ENU) in rats

N-ethyl-N-nitrosourea (ENU) administered intraperitoneally or transplacentally to Sprague-Dawley (CD) and BD-IV (Berlin Druckrey IV) rats increased the incidence (26.6%) of an uncommon ovarian tumor with testicular characteristics compared either to controls (3.0%) or rats administered diethylnitrosamine (3.3%). The induced tumors were composed of tubular structures that resembled seminiferous tubules lined by Sertoli's-like cells. The abundant electron-lucent cytoplasm of the tumor cells contained polyribosomes, lipid bodies, and mitochondria but few additional organelles. Sertoli's cell-like tumors appeared to develop from the ovarian stroma in the hilar region of the ovary. They usually were benign and resulted in unilateral enlargement of the ovary. The mean serum concentrations of testosterone, estrone, and estradiol in selected rats with ovarian tumors were elevated above mean serum values in controls. There was not a consistent direct correlation between tumor diameter and circulating hormone level. Ethyl nitrosourea-induced ovarian tumors composed of testicular (Sertoli's-like) cells will provide a reproducible animal model to investigate the histogenesis and hormone secreting properties of this unique gonadal neoplasm.