Growth of abnormal tissue on penis.

SQUAMOUS CELL CARCINOMA

Patient: "Skipper", 20 year old Arabian gelding

Presenting complaint: ulcerated growth on the end of the penis

Skipper was presented to NW Equine for evaluation of a rapidly growing mass on the end of his penis. The 1mass was ulcerated and the end of the penis enlarged. Skipper had a complete physical examination including a biopsy evaluation of the tumor.The tumor had the characteristic appearance of 2squamous cell carcinoma. The mass appeared to involve only the end of the penis, and so it was recommended that Skipper have a 3partial penile amputation to remove the tumor completely. Unfortunately, the tumor was too large and involved too much of the end of the penis for removal of the tumor alone. It was also too large for 4chemotherapy alone to be successful.

Skipper had surgery the next day. The penile amputation procedure was successful.The end of his penis was reconstructed to give a more normal appearance and allow normal urination.The tumor was sent to a laboratory for microscopic analysis (5biopsy).The laboratory report indicated that the removal of the tumor was complete. Skipper recovered well from the surgery and was discharged from the hospital the next day. His owners report that Skipper has recovered fully at home with no signs of regrowth of the tumor.

1mass: a growth of abnormal tissue. Masses that form on the penis of the horse are unfortunately, relatively common. Different types of masses range from benign wart like growths, abscesses or skin reactions to parasite larvae (habronema), or tumors such as squamous cell carcinoma or sarcoid. Your veterinarian can usually get an idea from looking at the mass which type it is, but taking a biopsy of the tissue may be needed. It is important to clean the sheath (skin folds around the penis) of a male horse every 6 months or more, as needed to help prevent diseases of this area. Your veterinarian can demonstrate how to do this procedure.

2squamous cell carcinoma is a tumor (cancer) of skin cells. Squamous cell carcinoma is one of the more common types of tumors diagnosed in the horse. It usually affects areas with little hair and lack of pigment (pink skin) such as the muzzle, skin around the eyes, penis and sheath in males, and around the vulva in females. Just like in people, this tumor is sometimes linked to exposure to sun (ultraviolet radiation), especially when it occurs on the muzzle and around the eyes in horses with white faces. The tumor destroys the normal tissue around it and slowly invades it. It can sometimes metastasize (spread) to regional lymph nodes in advanced cases. Removing the tumor and surrounding tissue can control it. If discovered very early, it can sometimes be removed before it destroys the surrounding tissue.

3penile amputation: Amputation of the penis is necessary when a tumor or traumatic incident destroys the end of the penis.The affected tissue is removed with the horse under general anesthesia and the end of the penis and urethra are reconstructed to allow normal function.

4chemotherapy: Application or treatment with drugs that selectively kill tumor cells. Drugs used in horses with squamous cell carcinoma include 5-fluorouracil and cisplatin. These drugs can be of benefit in a very small tumor or when complete removal of the tumor is not possible, such as around the eye. Other methods of combating tumors include cryotherapy (freezing) and irradiation. Your veterinarian will determine which if the best treatment for each individual horse.

5biopsy: Examination of tissue under a microscope. This procedure is very important to determine the type of tumor and how likely it is to spread.It is also important to evaluate tissue to determine whether the entire tumor has been removed after surgery.

The diseased end of the penis is removed.

The end of the penis is reconstructed.

A new urethral opening is made in the penis.