Fibromatous and Ossifying Epulides

•benign

•fibromatous epulis is the most common epulis (57%) followed by ossifying (23%), acanthomatous (18%), and giant cell epulis (2%)

•mean age 8-9 years with male predisposition

•site: maxillary premolar teeth

•gross appearance: pedunculated masses arising from the periodontal ligament and extending through gingival sulcus

•ossifying epulis has a broader base of attachment and are less pedunculated than fibromatous epulis

•fibromatous and ossifying epulides are not ulcerative or invasive, covered by epithelium, and are grossly similar to gingival hyperplasia

•classification of ossifying or fibromatous depends on the histologic presence or absence of bone

•treatment: conservative surgical excision ± cryosurgery or electrocautery

•recurrence is common in cats with multiple epulides

Acanthomatous Epulides

Biologic Behaviour

•mean age 7.8 years

•no sex predisposition

•breed predisposition: Shetland Sheepdog

•site: mandibular canines (60%) and incisors

•acanthomatous epulides are locally invasive with bone lysis but do not metastasize

•epulides arise from the periodontal stroma or ligament

•80%-90% of dogs have radiographic evidence of bone involvement

Treatment

•surgery is recommended with either mandibulectomy and maxillectomy because of bone invasion

•acanthomatous epulis is also radiation sensitive with 95% local cure rate, however, malignant transformation of the irradiated mass has been reported in 5%-20% dogs following orthovoltage radiation therapy

•intralesional bleomycin (q 7 days for 3-10 treatments) results in a 100% (4/4) CR with no local tumor recurrence after a minimum 1 year

Prognosis

•prognosis is excellent

•surgery: MST 36 months with 12-month survival rate 90% and 4% local tumor recurrence rate

•orthovoltage radiation therapy: MST 37 months with < 5% local tumor recurrence rate < 5% recurrence rate, but complications include 5%-20% malignant transformation and 6% bone necrosis