Sertoli Cell Tumor
Dr. Douglas Brum
Usually Sertoli cell tumors are found as incidental findings on a routine physical exam or an owner may notice a swelling on his pet's testicle. In most cases, the tumor causes no clinical problems; however, Sertoli cell tumors have the potential to be malignant and may cause other serious disease conditions. Enlargement of the mammary glands, possibly with the production of milk
Cryptorchid testicles with Sertoli cell tumors may become large enough to cause abdominal distention and pressure on other abdominal organs. This may cause abdominal discomfort or interference with internal organ function. Sertoli cell tumors may also produce excessive estrogen or decreased androgen production, which are changes in sex hormone concentrations. This increase in estrogen levels may lead to serious secondary conditions.
One such condition is known as a male feminizing syndrome. About 25 percent of Sertoli cell tumors cause this syndrome, but the percentage is even greater if a cryptorchid tumor is involved. The elevated estrogen hormones cause the male dog to take on some female characteristics, as well as display other typical signs.
The clinical signs associated with the feminizing syndrome include:
Skin changes that follow a pattern typical of an "endocrine alopecia": symmetrical hair loss starting in the hindquarters and genitalia
Increased skin pigmentation
A pendulous prepuce
Atrophy of the non-neoplastic testicle
Prostatic enlargement and disease (squamous metaplasia and prostatitis) may additionally be seen due to the changes in hormone levels. A much more severe and potentially life-threatening condition associated with chronic (long standing) elevated estrogen levels and Sertoli cell tumors is estrogen-induced bone marrow hypoplasia.
Elevated levels of estrogen have a toxic effect (estrogen toxicity) on the bone marrow, and bone marrow hypoplasia may develop where the cells in the bone marrow are damaged and cannot function properly. Since the cells in the bone marrow normally produce red blood cell, white blood cells and platelets (cells that help in clotting), decreases in all three cell lines may be seen (pancytopenia). This may lead to anemia (from the decreased red blood cells), infections (from the decreased white blood cells), and bleeding tendencies (from the decreased platelets). Bone marrow hypoplasia is the most serious potential sequelae of Sertoli cell tumors.
Other diseases that have similar clinical symptoms as Sertoli cell tumors include:
Other testicular tumors. Interstitial cell tumors and seminomas are other testicular tumors that cause masses on the testes. Both tumors are usually benign, and require aspiration or biopsy to confirm diagnosis.
Orchitis and epididymitis. Inflammations of the testicle and epididymis, the tube-like structure along side the testicle, are usually caused by a bacterial infection. The condition generally is painful, and dogs tend to feel ill. Affected dogs may also have a fever. If the infection is severe, the swelling in the testicle may begin to spread up the scrotum and into the inguinal area. Epididymitis may sometimes be caused by Brucella infection.
Testicular torsion is a twisting of the testicle where blood supply and or lymphatic drainage is compromised. The testicle is usually symmetrically enlarged and painful. The condition is often associated with testicular neoplasia. Testicular torsions occur with greater frequency in abdominal cryptorchid testes.
A spermatocele also called a sperm granuloma may occur due to a cyst-like dilation of the epididymis. Sperm may become trapped inside the dilation, and an inflammatory response may occur. This response may produce a small swelling in the epididymis. It is a benign condition, but may result in infertility.
An inguinoscrotal hernia occurs when abdominal contents pass into the scrotal sac. Most commonly, it is fatty tissue or a loop of bowel that enters through the inguinal canal. It is not a common condition.
If the tumor is located on a cryptorchid testicle and abdominal distention is present, other causes of abdominal swelling would need to be considered, for example other intra-abdominal masses or fluid accumulation.
If the typical alopecia (hair loss) is present with the feminizing syndrome, causes of endocrine alopecia need to be considered. These include: thyroid, adrenal, and growth hormone disorders as well as other causes of estrogen imbalances including oral estrogen administration.