Nodular skin problems encountered in a first-opinion equine clinic

Over an eight year period (2004-2011) 68 horses with nodular skin disease were diagnosed with 70 tumour like skin lesions. Diagnoses of the 70 nodular lesions were based on clinical features (5), cytology of fine needle aspirates(4), histological examination of either a biopsy or a complete surgical specimen (59) or on a combination of cytology and histology (2). Fifty-nine (84%) of the nodules proved to be genuine tumour like lesions and eleven (16%) were different forms of localised inflammatory dermatitis. Owners (93%) were very supportive of the need to perform histological or cytological investigations (65/70). Sarcoid was the most common nodular lesion (21) followed in order of occurrence by; melanoma (8), squamous cell carcinoma (8), nodular necrobiosis (7), mastocytoma (3), papilloma (2), maligne lymphoma (2), fibroma (2), naevus (1), botryomycosis (1), calcinosis circumscripta (1), collagen tumour (1), follicular hyperplasia (1) and follicular cyst (1). In the present study there was no breed predilection and the mean age of the group was 10.8 year (range 3-23 years). Melanoma occurred in 62.5% of the grey horses (5/8). Nodular necrobiose was only diagnosed in 10% of the cases , because when the nodule was noticed in the girth or saddle region no therapy was performed. Melanoma, nodular necrobiosis and sarcoids were in this relatively small study found on aspecific locations. In 70% (49/70) the nodules were surgical removed with either sedation and local anaesthesia (38) or general anaesthesia (11). Most patients (60.6%) were surgically treated at the practice (42/70). Of the 70 tumour-like lesions 61 lesions were scored for follow-up (for 8 cases no follow up was possible and one case had just started therapy); 64% (39/61) of the horses had no recurrence of the skin lesion(s) and the owners considerd their horses to be cured. Satisfaction rate as judged by owners was even higher: 80% (49/61).