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Traumatic pseudolipoma of the buccal mucosa
Traumatic pseudolipoma of the buccal mucosa R. I. Brooke, B.Ch.D., P.D.S.R.C.S.(Eng.), M.R.C.X., L.R.C.P., and A. J. MacGregor, M.Ch.D., B.D.X., P.D.S.R.C.S.(Eng.), Leeds, England
B
enign fatty tumors of the mouth are usually diagnosed as lipomas. Willis’ has pointed out the difficulty in distinguishing between this benign neoplasm and the hamartoma of fatty tissue. The literature concerning oral lipoma was reviewed by MacGregor and Dyson3 in 1966. Since that paper was prepared, further contributions have been made to the subject. Seldin and colleagues’ have contributed twenty-six new cases. Neider, in commenting upon an article by Choukas,4 pointed out that the frequency of this tumor may be greater than realized, since the smaller tumors are not reported. The histologic appearance of fatty tumors has been well summarized by Panders and Scherpenisse,5 and a comprehensive account of the differential diagnosis has been written by Haag and his co-workers.6 Oral lipoblastomatosis has also been reported for the first time by Shear.7 The origin of these tumors, whether neoplasms or hamartomas, is subject to the same type of doubt as that concerning aberrant growth in general. One of the factors mentioned with reservation is physical trauma. There is considerable difficulty in establishing a causal relationship because of the time lapse between the traumatic event and the diagnosis of lipoma. The following case presents dramatic evidence of how trauma might produce an appearance similar to lipoma. There is no suggestion here that this deformity is an aberration of growth at the genetic level, and this is the justification for the name traumatic pseudolipoma. Had the term pseudolipoma been used without qualification, it would have been possible for confusion to arise between the type of lesion described in this article and the precancerous tumor of the breast described by Shucksmith and Dossett.8 CASE REPORT A boy, 2 years 4 months of age, was brought to the Leeds Dental Hospital with a history of having fallen the previous evening, knocking his face against a chair. There had been bleeding from the mouth, but this had soon ceased. Later in the evening the mother had inspected the mouth and noticed a swelling on the inner aspect of the cheek. She was
223
224
Brooke and Mac&w-p~
Fig. 1. Intraoral
Fig. B. Histologic cation, x150.)
appearancc
appearance
O.K., O.M. & 0.1’. Arlpst, 1909
o-f trxumatic
showing
pscudoliporn:r.
mature
fat cells and absence of capsule.
(Magnifi-
certain that this lump had not been present prior to the accident. There was no history of any other disorder. Oral examination revealed a pedunculated swelling of the mucosa of the right cheek at the level of the occlusion of the molar teeth (Fig. 1). Coagulated blood was present around the base of the lesion at its attachment. The swelling was irregular in shape, its greatest diameter being some 2.5 cm. It was grayish yellow in color, soft in consistency, and had an uneven surface. No other oral abnormalities were detected. A complete physical examination yielded normal findings. Treatment
With the patient under general anesthesia, the lesion was excised by sharp dissection, and the wound was closed with sutures. Healing was rapid, and there has been no evidence of recurrence after 3 years. Pathology
cut
The specimen consisted of a soft nodule, its greatest diameter surface presented a yellow, greasy, homogeneous appearance.
measuring 2.5 cm. The The histologic appear-
Volume Number
28 2
Traumatic pseudolipoma of buccal mucosa
225
antes were those of adipose tissue infiltrated to a varying degree with neutrophil polymorphonuclear leukocytes. The fat cells were of the adult type. No evidence of a capsule was seen. There was a layer of coagulated blood on the surface of the lesion (Fig. 2).
DISCUSSION
The buccal pad of fat is a thinly encapsulated mass of adipose tissue which lies in the cheek, wedged between the buccinstor and masseter muscles. It extends anteriorly in front of the masseter. Posteriorly, it is continuous with the larger body of fat which lies between the temporal and pterygoid muscles, extensions of which pass over the outer surface of the temporal muscle and into the pterygomandibular space. Sicher” has emphasized that this pad of fat may be a possible source of confusion in the diagnosis of lipoma. It is common experience when operating in this region (for example, for the removal of a fibroepithelial polyp) to encounter fat if the buccinator is incised. Occasionally, fatty tissue extrudes into a lower third molar wound at operation. The most likely interpretation of the findings in this case is that the patient had bitten through both the mucosa and the buccinator, producing a deficiency which allowed herniation of the buccal pad of fat. He was examined about 12 hours a,fter the injury, but even at this stage the lesion had many features resembling lipoma. It may be speculated that if healing had occurred, the lesion would have become covered with epithelium, making it clinically indistinguishable from a lipoma. An alternative diagnosis is that the patient had merely bitten into a previously existing lipoma. This view would appear to be invalidated by the confident assurance of the mother that the swelling had not been present before the accident. Moreover, no capsule was demonstrated histologically. Thanks are due Mr. P. Hart for the photographs.
for making
the histologic
preparations
and Mr. L. Jepson
REFERENCES
1. Willis, R. A.: Pathology of Tumours, ed. 4, London, Butterworth & Co., Ltd., p. 672. 2. Seldin, H. M., Seldin, S. D., and Rakower, W.: Lipomas of the Oral Cavity: Report of 26 Cases, J. Oral Surg. 25: 270,1967. 3. MacGregor, A. J., and Dyson, D. P.: Oral Lipoma; a Review of the Literature and a Report of Twelve New Cases, ORAL SURG., ORAL MED. & ORAL PATH. 9: 376, 1966. 4. Choukas, N. C.: Lipoma of Buccal Wall: Report of a Case, J. Oral Surg. 25: 371, 1967. 5. Panders, A. K., and Scherpenisse, L. A.: Oral Lipoma! Brit. J. Oral Surg. 5: 33, 1967. 6. Haag, R., Nicholas, P., and Frank, R. M.: Contributrers a l’etude du fibro-lipome de Ia cavite buccale, Rev. franp. odonto-stomatol. 14: 1629, 1967. 7. Shear, M.: Lrpoblastomatosis of the Cheek, Brit. J. Oral Surg. 5: 173, 1967. 8. Shucksmith, H. S., and Dossett, J. A.: Pseudolipoma of the Breast: A Mask for Cancer, Brit. M. J. 2: 1459-1462, 1962. 9. Sicher, H.: Anatomy and Oral Pathology, ORAL SURG., ORAL MED. L%ORAL PATH. 21: 770? 1962.
B
enign fatty tumors of the mouth are usually diagnosed as lipomas. Willis’ has pointed out the difficulty in distinguishing between this benign neoplasm and the hamartoma of fatty tissue. The literature concerning oral lipoma was reviewed by MacGregor and Dyson3 in 1966. Since that paper was prepared, further contributions have been made to the subject. Seldin and colleagues’ have contributed twenty-six new cases. Neider, in commenting upon an article by Choukas,4 pointed out that the frequency of this tumor may be greater than realized, since the smaller tumors are not reported. The histologic appearance of fatty tumors has been well summarized by Panders and Scherpenisse,5 and a comprehensive account of the differential diagnosis has been written by Haag and his co-workers.6 Oral lipoblastomatosis has also been reported for the first time by Shear.7 The origin of these tumors, whether neoplasms or hamartomas, is subject to the same type of doubt as that concerning aberrant growth in general. One of the factors mentioned with reservation is physical trauma. There is considerable difficulty in establishing a causal relationship because of the time lapse between the traumatic event and the diagnosis of lipoma. The following case presents dramatic evidence of how trauma might produce an appearance similar to lipoma. There is no suggestion here that this deformity is an aberration of growth at the genetic level, and this is the justification for the name traumatic pseudolipoma. Had the term pseudolipoma been used without qualification, it would have been possible for confusion to arise between the type of lesion described in this article and the precancerous tumor of the breast described by Shucksmith and Dossett.8 CASE REPORT A boy, 2 years 4 months of age, was brought to the Leeds Dental Hospital with a history of having fallen the previous evening, knocking his face against a chair. There had been bleeding from the mouth, but this had soon ceased. Later in the evening the mother had inspected the mouth and noticed a swelling on the inner aspect of the cheek. She was
223
224
Brooke and Mac&w-p~
Fig. 1. Intraoral
Fig. B. Histologic cation, x150.)
appearancc
appearance
O.K., O.M. & 0.1’. Arlpst, 1909
o-f trxumatic
showing
pscudoliporn:r.
mature
fat cells and absence of capsule.
(Magnifi-
certain that this lump had not been present prior to the accident. There was no history of any other disorder. Oral examination revealed a pedunculated swelling of the mucosa of the right cheek at the level of the occlusion of the molar teeth (Fig. 1). Coagulated blood was present around the base of the lesion at its attachment. The swelling was irregular in shape, its greatest diameter being some 2.5 cm. It was grayish yellow in color, soft in consistency, and had an uneven surface. No other oral abnormalities were detected. A complete physical examination yielded normal findings. Treatment
With the patient under general anesthesia, the lesion was excised by sharp dissection, and the wound was closed with sutures. Healing was rapid, and there has been no evidence of recurrence after 3 years. Pathology
cut
The specimen consisted of a soft nodule, its greatest diameter surface presented a yellow, greasy, homogeneous appearance.
measuring 2.5 cm. The The histologic appear-
Volume Number
28 2
Traumatic pseudolipoma of buccal mucosa
225
antes were those of adipose tissue infiltrated to a varying degree with neutrophil polymorphonuclear leukocytes. The fat cells were of the adult type. No evidence of a capsule was seen. There was a layer of coagulated blood on the surface of the lesion (Fig. 2).
DISCUSSION
The buccal pad of fat is a thinly encapsulated mass of adipose tissue which lies in the cheek, wedged between the buccinstor and masseter muscles. It extends anteriorly in front of the masseter. Posteriorly, it is continuous with the larger body of fat which lies between the temporal and pterygoid muscles, extensions of which pass over the outer surface of the temporal muscle and into the pterygomandibular space. Sicher” has emphasized that this pad of fat may be a possible source of confusion in the diagnosis of lipoma. It is common experience when operating in this region (for example, for the removal of a fibroepithelial polyp) to encounter fat if the buccinator is incised. Occasionally, fatty tissue extrudes into a lower third molar wound at operation. The most likely interpretation of the findings in this case is that the patient had bitten through both the mucosa and the buccinator, producing a deficiency which allowed herniation of the buccal pad of fat. He was examined about 12 hours a,fter the injury, but even at this stage the lesion had many features resembling lipoma. It may be speculated that if healing had occurred, the lesion would have become covered with epithelium, making it clinically indistinguishable from a lipoma. An alternative diagnosis is that the patient had merely bitten into a previously existing lipoma. This view would appear to be invalidated by the confident assurance of the mother that the swelling had not been present before the accident. Moreover, no capsule was demonstrated histologically. Thanks are due Mr. P. Hart for the photographs.
for making
the histologic
preparations
and Mr. L. Jepson
REFERENCES
1. Willis, R. A.: Pathology of Tumours, ed. 4, London, Butterworth & Co., Ltd., p. 672. 2. Seldin, H. M., Seldin, S. D., and Rakower, W.: Lipomas of the Oral Cavity: Report of 26 Cases, J. Oral Surg. 25: 270,1967. 3. MacGregor, A. J., and Dyson, D. P.: Oral Lipoma; a Review of the Literature and a Report of Twelve New Cases, ORAL SURG., ORAL MED. & ORAL PATH. 9: 376, 1966. 4. Choukas, N. C.: Lipoma of Buccal Wall: Report of a Case, J. Oral Surg. 25: 371, 1967. 5. Panders, A. K., and Scherpenisse, L. A.: Oral Lipoma! Brit. J. Oral Surg. 5: 33, 1967. 6. Haag, R., Nicholas, P., and Frank, R. M.: Contributrers a l’etude du fibro-lipome de Ia cavite buccale, Rev. franp. odonto-stomatol. 14: 1629, 1967. 7. Shear, M.: Lrpoblastomatosis of the Cheek, Brit. J. Oral Surg. 5: 173, 1967. 8. Shucksmith, H. S., and Dossett, J. A.: Pseudolipoma of the Breast: A Mask for Cancer, Brit. M. J. 2: 1459-1462, 1962. 9. Sicher, H.: Anatomy and Oral Pathology, ORAL SURG., ORAL MED. L%ORAL PATH. 21: 770? 1962.