Intraosseous lipomas: Clinical features of a mandibular case with possible aetiology

British Journal of Oral and Maxillofacial Surgery (1986) 24, 459-163 0 1986 The British Association of Oral and Maxillofacial Surgeons

INTRAOSSEOUS

LIPOMAS: CASE

G.

R.

CLINICAL

WITH

BARKER,*

FEATURES

POSSIBLE MA.,

P. SLOAN,?

OF A MANDIBULAR

AETIOLOGY

F.D.S.R.C.S., F.R.C.S.Ed. and

B.D.S., PhD., M.R.C.Path.

*Department of Oral and Maxillofacial Surgery, und +Department Pathology and Oral Medicine, Manchester University Dental School, Cambridge Street, Manchester Ml5 6SH

of

Oral Higher

Summary. There are few reported cases of intraosscous lipoma of the jaws in the literature. The exact nature of these lesions is debatable, but it is widely accepted that they represent true benign tumours. In this presentation discussion is centered on a case of a lipomatoua lesion of the mandible and is the first to be reported in relation to a retained apex. The features for and against this lesion being of a neoplastic origin are discussed. The characteristic histopathological finding was the presence of only mature adipose fat cells.

Introduction lipomas have previously been reported in the long bones (Hart, 1973; Leeson et al., 1983) and rarely in the jaws (Miller et al., 1982). At the Mayo Clinic, Dahlin (1957) recorded an incidence of less than one per thousand bone tumours diagnosed and Wilner (1982) found only 32 recorded cases in a comprehensive literature review. Thus, true intraosseous lipoma appears to be the rarest primary tumour of bone (Leeson et al., 1983). The present paper records a rare case of intraosseous lipoma of the mandible and reviews the clinical, radiographic and histopathological findings in previously reported cases in the jaws. There are no pathognomonic histological features to differentiate the diagnosis of intraosseous lipoma from a developmental, marrow defect or ‘reactive’ increase in adipose tissue. Intraosseous

Case Report

A 53 year-old housewife, who was under medical treatment with antihypertensive and anti-depressant medication, was seen for the removal of symptomless retained roots, prior to the construction of partial dentures. Routine radiological examination confirmed the presence of retained third molar roots and also revealed a radiolucent area in the lower right third molar region. This area was of even radiodensity and lay above the inferior alveolar canal and was entirely within bone. The lesion was 1 cm in diameter and resembled a cyst, having a rounded denser almost corticated margin. The margin of the radiolucency was complete and regular in outline (Fig. 1). A root apex was noted to be lying horizontally, immediately beneath the radiolucency. From the clinical history and radiological examination a provisional diagnosis of an inflammatory cyst in relation to the retained apex of the lower third molar was made. The third molar region was explored surgically under local anaesthesia. The buccal plate of bone appeared intact and showed a normal periosteal appearance (Received

23 December

1985: uccepred

459

15 January

1983)

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overlying a cortical plate which was not expanded. A window separated readily from the underlying lesion, was removed from to reveal an underlying mass which had a yellow, smooth but surface. Lobules of fat were identified in the blood, oozing from The lesion itself was soft and readily separated from the bone,

I

Fig. Figure

1-Radiolucent

arca

and retained

root

of bone, which the buccal aspect slightly lobulated the surgical site. and floated when

apex

from

the Iowcr

left third

molar

Fig. 2 Figure

Z-High

power

view of adipose

tissue to show mature

fat cells

region

IN’I‘RAOSSEOUS

461

LIPOMAS

placed in the 10% buffered formalin fixative. The resulting bone cavity had smooth walls without communication to the oral mucosa. There was no recognisable capsular structure and the resultant bony defect was clean and free from any soft tissue attachments. Cancellous bone lined the anterior, posterior and inferior aspects. The root apex was noted to be lying beneath the floor of the cavity enclosed within the bone on all but its uppermost aspect. Histopathological examination of the curetted lesion included serial sections and showed the presence of mature adipose tissue (Fig. 2). There wds no evidence of fibrosis or inflammation. Tiny fragments of bone from the edge of the lesion were examined and found to have the characteristic features of viable bone which possessed a lamellar structure when viewed with polarised light. There was no evidence of any capsular tissue lying on the bone surface of the specimen. The root apices were also examined and showed no abnormal features or evidence of inflammatory cells. Discussion lntraosseous deposits of adipose tissue have been reported in several bones. In 1880 the first case was described (Cornil & Ranvier) which invofved the diaphysis of the femur. No further details were given except that cortical erosion was present. Other cases were described in the femur, fibula, maxilla, tibia, ulna, clacaneus and frontal bones (Brault, 1901; Whersig, 1910; Mead, 1946; Dickinson et al., 1951; Caruolo & Dahlin, 1953; Child, 1955; Dahlin, 1957). Intraosseous lipomas have been described in the body of the mandible (Oringer, 1948; Miller et al., 1982; Heir 8r Geron, 1983) and in the ramus (Johnson, 1969). In addition a fibrolipoma (Newman. 1957) and an angiolipoma (Polte, et al., 1976) have been described. All these lipomas were noted to appear as radiolucencies and are listed in Table I. Lipomas occur also in the soft tissues of the mouth and compared with Table I Summary Histology Lipoma

of the published Author .-___. Oringer ( 1948)

Sex

Site

37

F

Under -i

Newman (1957)

65

Lipoma

Johnson (1969) Poke et 01. (1976) Miller ef (11. ( 1982)

21

Lipoma

Lipoma

Lipoma

Heir & Geron (1983) Prcscnt case

of intraosseous

Age

Fihrolipoma

Angiolipoma

cases

roots

Near q but not connected Cyst around 87 Body of mandible Impicted

39 51

lipoma X-ray

Clinical

Radiolucency

Pain made worse with chewing and pressure in the left molar area

53

F

Left anterior mandibular ramus Ret$ned apex

features

Radioluccncy

Radioluccnq Radiolucency Radiolucency

8 43

of the jaws

Radiolucency

Radiolucency

Hypcraesthesia of the chin area Impacted lower third molar Periodontal disease Trigeminal neuropathy ReGined

apex

of

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intraosseous lipomas, they occur relatively frequently and are most commonly found in the fourth and fifth decades (Hatziotis, 1971). There is no specific sex dominance although Cannel1 et al. (1976) reported that soft tissue lipomas of the buccal mucosa occurred almost exclusively in men, whereas those in the floor of the mouth and retromolar area occurred more commonly in women. The most frequent site is the buccal mucosa followed by the tongue, floor of mouth, buccal sulcus and vestibule, palate, lips and gingiva (Pindborg, 1980). In the published cases of intraosseous lipoma, most presented in the long bones, predominantly in the fourth decade and like soft tissue lipomas, they are reported to be relatively painless and are presumed to be slow growing. It is interesting to combine these features with the ageing processes of long bones in which fatty degeneration of the bone marrow (Geschickter, 1934) results in fat cells becoming more abundant. In this respect the mandible also displays the same property. Therefore, at the age at which intraosseous lipomas present, fat cells are abundant in the mandible and long bones and it seems likely that intraosseous lipomas are derived from the fatty marrow. Whether they represent true neoplasms or space filling marrow defects is uncertain and despite the presence of fat cells in the marrow of the adult, intraosseous lipomas remain very rare lesions. A preceding history of trauma, fracture and later pain which necessitated the radiological examination at which the lipomas were diagnosed is the presenting feature of long bone cases. In this present case of mandibular intraosseous lipoma there must have been localised trauma during the removal of the tooth as evidenced by the fracture and retention of the root apex. In the absence of any clinical or radiological evidence of inflammation or degeneration it would appear that trauma was one of the more plausible aetiologies of the lesion. However. trauma to the mandible is common and the finding of an intraosseous lipoma is uncommon. This may be because trauma can exert its effect indirectly, disrupting the blood supply and leading to a disorganised healing process. There is evidence that infarction and nutritional compromise in long bones may be aetiological factors in intraosseous lipomas (Hart, 1973). With regard to the mandible, histological studies have shown that the inferior dental artery supplies the angle and the body of the mandible. With increasing age this arterial blood supply becomes obliterated and the periosteal blood vessels come to supply the cortex and adjacent cancellous bone (Lavelle, 1975). If the nutrient vessels from the inferior dental artery become obliterated, areas of infarction may develop. Within these areas fat cells of the marrow may accumulate to form a ‘lipomatous mass.’ Areas of infarction are known to occur in fatty marrow and have been described in the inner cortex of bone overlying an intraosseous a correlation between lipoma by Bagnoud et al. (1967), who also demonstrated intraosseous lipomas in the metaphyses of long bones with the distribution of chronic infarcts. Physical trauma to the periosteum is common in long bones and in the mandible. If trauma, ageing and blood vessel infarction were precipitating factors in intraosseous lipomas there should also be periosteal lipomas. These have been reported (Geschickter, 1934; Bartlett, 1930) in the long bones and also in the mandible (Steiner et al., 1981). Other bones which suffer repeated minor trauma, for example, vertebral bodies have been reported to develop intraosseous lipomas (Dickinson et al., 1951). Trauma may not have been the only factor in the present case; an apical bony defect could have arisen as a result of infection and the accumulation of fat cells at

INTRAOSSEOUS

463

LIPOMAS

the apex may thus represent

the end stage of the resultant pathological process. osteoporosis could be a further explanation and the cyst-like appearance of the cavity in the alveolar bone would support this, but there was a distinct lack of osteoblastic and osteoclastic activity and no cortical thinning around the lesion. Finally, a true benign tumour would not necessarily be expected to have a

Local&d

capsule.

Encapsulated

reported

a well encapsulated

yellowish

white

and

tumours

in bone

slightly

consisted

have been described.

lobulated

of adult

fatty

fibrolipoma tissue;

the

Bartlett

(1930)

whose cut surface capsule

was

periosteum capsule on either and

merged together. In this present case there was no detectable In the other published cases of clikcal or histopathological examination. intraosseous lipomas the presence of a capsule was not clearly described. The recommended treatment is simple conservative excision as there have been no reported cases of recurrence or malignant change. Similarly in long bones (Leeson et al., 1983), curettage with or without bone grafting is the treatment of choice. References

Appenzeller,J. & Weitzner, S. (1974).

lipoma of OS calcis. Clinical Orlhopaedics, 101, 171. F., The Voz. F. & Taillard, W. (1967). Le lipome intra-osseux expression d’un infarctus chronique. Journal de Chirurgie, 94, 165. Bartlett, E. 1. (1930). Periosteal lipoma: report of two cases. Archive.y of Surgery, 21, 1015. Brault, A. (1901). Des Tumeurs. In Manuel D’Histologie Pafhologique. Ed. V. Cornil & L. Anvier, Edition no. 3. Vol. 1. p. 393. Balliere et Cie. Paris. Cannell, H., Langdon, J. D., Patel. M. F. & Rapidis, A. D. (1976). Lipomata in oral tissues. Journal of Maxilla-facial Surgery, 12, 3. Caruolo, J. E. & Dahlin, D. C. (1953). Lipoma involving bone and simulating malignant bone tumour. Report of a case. Proceedings Staff Meetings, Mayo Clinic, 28, 361. Child, P. L. (1955). Lipoma of OS calcis. Report of a case. American Journal of Clinical Pathology, 25, 1050. Cornil, V. & Ranvier, L. (1869). Manuel d’histologie pathologique, 1, 393. Mnnunl of Pathological Histology. (1880). Translation with notes and additions by Shakespeare, E. 0. and Simes. J. H. p. 784. Philadelphia. Dahlin, D. C. (1957). Bone Turnours. 9@93 Ed. Charles C. Thomas, Springfield, Illinois. Dickinson, A. B., Ayres, W. W.. Mason. M. W. & Miller, W. R. (1951 J. Lipoma of bone of intraosseous origin. Journal of Bone and Joint Surgery, 33A, 257. Geschickter, C. G. (1934). Lipomid tumours. American Journul of Cancer, 21, 617. Hart, J. (1973). Intraosseous lipoma. Journal of Bone and Joint Surgery, 559, 624. Hatziotis, J. C. (1971). Lipoma of the oral cavity. Oral Surgery, Oral Medicine, Oral Pathology, 31,511. intraosseous lipoma related to crigeminal neuropathy. Heir, G. M. & Geron, P. R. (1983). Mandibular Clinical Preventive Dentistry, 5, 13. Johnson, E. C. (1969). Intraosseous lipomas: report of case. Journal of Orul Surgery, 27, 868. Lavek C. L. B. (1975). The blood supply of oral tissues. In: Applied Physiology of the Mouth, p. 269. John Wright, Bristol. Leeson, M. C., Kay, D. & Smith. B. S. (1983). Intraosseous lipoma. Clinical Orthopedics and Related Research, 181, 186. Mead, S. V. (1946). Oral Surgery. Edition No. 3, p. 1213. St. Louis, C. V. Mosby Co. Miller, W. B., Ausich. J. E.. McDaniel, R. K. & Longo. J. J. f 1982). Mandibular intraosseous linoma. Journal of Oral and Maxillofacial Surgery> 40,“594. ’ Newman,C. W. (1957). Fibrolipoma of the mandible: report of case. Journul of Oral Surgery, 15, 251. Oringer, M. J. (1948). Lipoma of the mandible. Oral Surgery, Oral Medicine, Oral Pathology, 1, 1134. Pindborg, J. J. (1980). Atlas ofDiseuses ofthe Oral Mucosa, p. 102. W. B. Saunders & Co. Philadelphia, Pennsylvania. Polte, H. W., Kollony. S. C. & Hooker. S. P. (1976). Lipoma of mandible. Oral Surgery. Oral Medicine. Oral Pufhology 41, 637. Steiner. M., Gould, A. R., Rasmussen. & LaBriola. D. (1981). Parosteal lipoma of the mandible. Oral Surgery, Oral Medicine, Oral Pathologytv, 52, 61. Whersig (1910). Lipom des Knochenmarks. Zentralhlatt fiir allgeneinr Pathologic und pathologische Anatomie, 21, 243. Wilner, D. (1982). Radiology of Bone Tumours and Allied Disorder.s, p. 387. Philadelphia. W. B. Saunders. Bagnoud,

Intraosseous