Epulides (periodontal tumours) in cats (a review of 13 cases)

©L. M. A. Colgin, F. Y. Schulman and R. R. Dubielzig Multiple Epulides in 13 Cats Vet Pathol 38:227-229 (2001) http://www.vetpathology.org/cgi/content/full/38/2/227

Epulides, tumours of periodontal ligament origin, are common in dogs but occur infrequently in cats.1,2,5–13 They account for 0–7.8% of tumours in surveys of feline oral neoplasms.5,6,9,11,12 Histologically, they are characterized by a dense, well-vascularized stroma populated by stellate cells with abundant fibrillar collagen and resemble the periodontal ligament.

Microscopically, these epulides are nonencapsulated, poorly demarcated, infiltrative, well-vascularized, highly cellular neoplasms. They expand the gingiva and are composed of haphazardly arranged, spindle-shaped, occasionally stellate cells surrounded by a moderate amount of fibrillar collagen. Neoplastic cells have indistinct borders and a small amount of eosinophilic, often microvacuolated, cytoplasm. Nuclei are irregularly oval, occasionally angular, with finely stippled chromatin and one small, variably distinct nucleolus. Anisokaryosis is not evident and mitotic figures are rare (Fig. 1). In 11 cases (Nos. 3–13), these cells are multifocally surrounded foci of dense, brightly eosinophilic material (interpreted as dental hard substance) that was occasionally mineralized (Fig. 2). All tumours exhibited marked epithelial hyperplasia of the overlying gingiva, often with prominent down-growth of anastomosing epithelial cords. There is multifocal erosion and ulceration with an associated neutrophilic inflammatory infiltrate. Low to moderate numbers of perivascular lymphocytes and plasma cells admixed with fewer macrophages are scattered throughout the neoplasms.

Fig. 1. Fibromatous and ossifying epulis; cat No. 3. A moderate amount of fibrillar collagen surrounds neoplastic cells that are spindle-shaped and have a small amount of eosinophilic, often vacuolated cytoplasm. The nuclei are irregularly oval with finely stippled chromatin and one small nucleolus. HE. Bar = 17 µm.
Fig. 2. Fibromatous and ossifying epulis; cat No. 5. Proliferative periodontal ligament stroma with foci of dental hard substance. HE. Bar = 170 µm.

Although fibromatous epulis has been reported in cats, this is the first report of multiple, concurrent epulides in this species. The hallmark of fibromatous and ossifying epulis is a well-vascularized collagenous stroma populated by stellate cells.1,2,7,8,10,12 The ossifying epulis contains osteoid or cementin-like or dentin-like material often referred to as dental hard substance.2,7,8,10,12 We consider the fibromatous and ossifying epulis to be a histologic variant of the fibromatous epulis. The histologic features of canine epulis and multiple feline epulides are similar; however, in general, the feline tumours detailed in this report were more cellular. The apparent human counterpart to fibromatous epulis in dogs is the peripheral odontogenic fibroma. Unlike its canine counterpart, this neoplasm is rare.8

There are conflicting views on the biologic behaviour and treatment of canine fibromatous epulis in the literature. Head stated that canine fibromatous and ossifying epulides recur following surgery but did not indicate the frequency,10 while Barker et al. stated that excision is curative.2 Bostock and White reported three recurrences in 17 cases of canine fibromatous and ossifying epulis following excision of the tumour without removal of the underlying bone.4 Gardner recommended complete excision of the canine fibromatous epulides but did not feel that the en bloc resection of bone and extraction of associated teeth favoured by Bjorling et al. was necessary.3,8 Gardner further stated that these lesions have no tendency to recur and that those that recurred were most likely secondary to incomplete excision. In our experience (RRD, FYS), canine fibromatous epulides are usually successfully treated by local excision and recurrence occurs infrequently, whereas recurrence was observed in 8 of 11 (72%) of the cats in this series for which follow-up information was available.

In summary, although the number of cases is too small to definitively assess the biological behaviour of multiple feline epulides, certain statements about the biological behaviour and treatment can be made. These tumours were found in cats that ranged from 1 to 15 years of age. Six of the 12 cats whose age was reported were 3 years old or younger, suggesting a higher prevalence in young cats. There was no sex predilection. The FeLV status was negative in the four cats tested, suggesting that there is no association between this lesion and feline leukemia virus infection. Glucocorticoid therapy was not beneficial in treating four of five cats. Unlike canine fibromatous epulides, multiple feline epulides appear to recur frequently after surgical excision; consequently, wide surgical excision is indicated.

  1. Andrew AD, Carpenter JL, Holzworth J: Tumors and tumor-like lesions. In: Diseases of the Cat, Medicine and Surgery, ed. Holzworth J, vol. 1, pp 487-488, WB Saunders, Philadelphia, PA 1987
  2. Barker I, Van Dreumel AA, Palmer NC: The alimentary system. In: Pathology of Domestic Animals, ed. Jubb KVF, Kennedy PC, and Palmer NC, 4th ed., pp 22-24, Academic Press, San Diego, CA 1993
  3. Bjorling DE, Chambers JN, Mahaffey EA: Surgical treatment of epulides in dogs: 25 cases (1974–1984). J Am Vet Med Assoc 190:1315-1318, 1987[Medline]
  4. Bostock DE, White RAS: Classification and behaviour after surgery of canine epulides. J Comp Path 97:197-206, 1987[Medline]
  5. Brodey RS: Alimentary tract neoplasms in the cat: a clinicopathologic survey of 46 cases. Am J Vet Res 27:74-80, 1966
  6. Dorn CR, Priester WA: Epidemiologic analysis of oral and pharyngeal cancer in dogs, cats, horses and cattle. J Am Vet Med Assoc 169:1202-1206, 1976[Medline]
  7. Dubielzig RR: Proliferative dental and gingival diseases of dogs and cats. J Am Anim Hosp Assoc 18:577-584, 1982
  8. Gardner DG: Epulides in the dog: a review. J Oral Pathol Med 25:32-37, 1996[Medline]
  9. Gorlin RJ, Barron CN: The oral and pharyngeal pathology of domestic animals: a study of 487 cases. Am J Vet Res 20:1037-1038, 1959
  10. Head KW: Tumors of the alimentary tract. In: Tumors in Domestic Animals, ed. Moulton JE, 3rd ed., pp 348356-362, University of California Press, Berkeley, CA 1990
  11. Patnaik AK, Liu SK, Hurvitz AI, McClelland AJ: Nonhematopoietic neoplasms in cats. J Natl Cancer Inst 54:855-860, 1975[Medline]
  12. Stebbins KE, Morse CC, Goldschmidt MH: Feline oral neoplasia: a ten-year survey. Vet Pathol 26:121-128, 1989[Abstract]
  13. Vos JH, Van der Gaag I: Canine and feline oral-pharyngeal tumours. J Vet Med A 34:420-427, 1987