- Email: [email protected]
Lipoblastomatosis of the cheek
LIPOBLASTOMATOSIS
OF THE
CHEEK
MERVYN SHEAR, M.D.S., M.C.PATH. Joint Oral Pathology Unit, University of the IVitwatersrand and South African Institute for Medical Research, Johannesburg, South Africa LIPOBLASTOMATOSIS is a rare lesion of fat cells which has not previously been recorded in the oral tissues. Its nature was first recognised by Vellios et al. (I958), who gave it its present name. Their case involved the pectoral region and axilla in a girl aged 8 months. These authors studied the embryogenesis of adipose tissue in human foetuses and found that although the formation of fat lobules appears to cease in late foetal or early post-natal life, the differentiation of individual lipoblasts may continue. In certain areas such as the axilla, mediastinum and retroperitoneum, fat cells may not attain adult form at the time of birth. They believe that lipoblastomatosis occurs when there is continued proliferation of lipoblasts and of new lobules of adipose tissue in the post-natal period. In a review of 27 fatty turnouts, Kauffman and Stout (I959) describe four cases of lipoblastomatosis, one of which was the case previously reported by Vellios et aL They emphasise the lobulated nature of these masses and state that although areas of active lipogenesis are commonly found they are potentially less dangerous than liposarcomas because of their restricted nodular growth. They do, however, point out that they may recur if inadequately excised. Of the three previously unreported cases in the series recorded by Kauffman and Stout, two occurred in males and all were noticed during the first year of life. One occurred in the neck and mediastinum, one in the buttock and one in the chest wall. Only the latter case recurred, three months after treatment. The others have been followed, with no evidence of recurrence, for two and a half years and eight months, respectively (Table I). A case occurring in the popliteal region of a Ig-month-old child is reported by Enterline et al. (196o). There was a three-month history of an enlarging TABLE I
CASES OF LIPOBLASTOMATOSIS Author(s)
Site
I. Vellios et al. 2. Kauffman and Stout 3. Kauffman and Stout 4. Kauffman and Stout 5- Enterline et aL 6. van Meurs 7. Shear
Pectoral Neck/mediastinum Buttock Chest wall
Recurrence Follow-up
Sex
Operation
F M
Dissected free Excised
No
4
No
2½ yr. 2½ yr.
6½
M
Excised
No
8 mo.
4~
F
Not well demarcated Invaded muscle Not excised Dissected free
Yes 3 mo.
4 mo.
Age Months
M
Popliteal Axilla Cheek
8
I9 F M r73
Yes × 4
20 m o .
174
B R I T I S H JOURNAL OF ORAL SURGERY
t u m o u r and at operation an encapsulated mass was found which extended into the adjacent gastrocnemius muscle. T h e t u m o u r had a lobular pattern and a well-defined lobular blood supply. It was composed o f mature fat cells with areas o f immature cells. Vellios et al. believe that the case described by van Meurs (1947) as an embryonic lipoma may have been one o f lipoblastomatosis. Van Meurs' case was one o f a fatty t u m o u r in the right axilla o f a 5-month-old girl. T h e t u m o u r recurred four times and the child had five operations between the ages o f 5 and 25 months. Histological examination at successive operations showed relatively more and more adult tissue. In the earlier specimens myxomatous tissue predominated whereas later the lesion was more lipomatous. Van Meurs felt that the t u m o u r arose from persistent embryonic adipose tissue in the interscapular area b u t remained under the influence o f factors controlling cell growth so that it was altered into an innocent tumour.
CASE R E P O R T An African child of I8 months was admitted to hospital with a mass on the mucosal surface of the cheek close to the opening of the parotid duct. The surgeon was not able to elicit accurately how long the swelling had been present nor the rapidity of growth. At operation, the tumour appeared to enucleate completely. The patient has not been seen since discharge and attempts to locate the family have been unsuccessful. P a t h o l o g y . The fixed specimen was a dark, ovoid, soft tissue mass measuring 3o× 2o× IO mm. The surface was smooth and the cut surface was darkly coloured, homogeneous, and did not resemble adult fat. Histological examination of the specimen at low magnification shows a distinctly lobulated pattern (Fig. In). On the surface there is a band of fibrinous and necrotic material enmeshed in which are numerous inflammatory cells. The interlobular septa, which are densely infiltrated with polymorphonuclear leukocytes, have a loose myxoid appearance but are irregularly and only faintly metachromatic with toluidine blue (Fig. 1a). Many bacteria can be demonstrated in the septa and in the surface tissue. At slightly higher magnification (Fig. IC) the lobules are seen to comprise mainly adult fat cells, but interspersed with these are many lipoblasts in various stages of differentiation. In each lobule there is a diffuse capillary network. Lipofuscin pigment is present at the periphery of many of the fat cells. The majority of lipoblasts are large round or ovoid cells (Fig. 2A and B) but some smaller spindle and stellate forms are seen (Fig. 2c). Their nuclei are plump, eccentric and pyknotic. Mitoses are present (Fig. 2D) but no bizarre forms are seen. Three lipoblasts in varying stages of development are illustrated in Figure 2A. At an early stage they have a granular, eosinophilic cytoplasm containing numerous small vacuoles. These vacuoles coalesce, forming a progressively larger vacuole while the granular cytoplasm is compressed to the periphery of the cell. Special stains demonstrate the presence of neutral fat in some of the lipoblasts (Fig. 2B). Lipoblasts and lipocytes are also seen in the interlobular septa (Fig. IB).
DISCUSSION I n naming this entity 'lipoblastomatosis' the implication o f Vellios and his co-workers is clearly that it is not a neoplasm but a continuation o f the normal
LIPOBLASTOMATOSIS
FIG.
OF
THE
CHEEK
IA
Distinctly lobulated pattern which is characteristic of lipoblastomatosis. H. a n d E . x4o. FIG. IB The interlobular septa have a loose myxoid appearance and contain lipoblasts and lipocytes. I n this case there is a dense inflammatory cell infiltrate. Lipofuscin pigment is present at the periphery of many of the fat cells. H. and E. x 12o. FIG. IC The lobules comprise mainly adult fat cells but many lipoblasts are interspersed. A diffuse capillary network is present in each lobule. H. and E. ×15o.
175
176
BRITISH JOURNAL OF ORAL SURGERY
process o f foetal fat development carried into post-natal life. T h e y arc supported in this opinion by K a u f f m a n and Stout, Enterline e t al. (I96O) and Willis (I962). T h e latter author believes that the lesion is in the group of adipose h a m a r t o m a and congenital liporna and catls it a 'congenital lipomatoid growth'. T h i s hypothesis is supported by three facts: the exclusive occurrence o f this lesion in infants; its location in sites of, and its histological resemblance to~ some of the stages of foetal fat formation; and the evidence provided b y van M c u r s '
~.
•
i~
B
A
FIG. 2A A number of lipoblasts are illustrated in this field. They are large ovoid to round cells with eccentric pyknotic nuclei. An early stage (A) shows the presence of numerous minute vacuoles in a granular eosinophilic cytoplasm. At B a large vacuole has formed by coalescence, and at C increase in size of the vacuole has compressed the cytoplasm to the periphery of the cell. H. and E. × 6oo. FIG. 2B Neutral fat in a lipoblast. Oil red O. x 6oo.
c FIG. 2C Spindle and stellate lipoblasts. Many polymorphonuclear leukocytes are present in this case. H. and E. × 480. FIG. 2D A lipoblast in mitosis. H. and E. × 360.
L I P O B L A S T O M A T O S I S OF THE CHEEK
177
case in which five consecutive biopsies showed progressive maturation of the adipose tissue. On the other hand, there are certain features which suggest a neoplastic character. One of the cases of Kauffman and Stout recurred after three months and the case of Enterline et al. was locally invasive. The present case enucleated readily and is distinctly lobulated, but the presence ofmyxoid tissue and numerous lipoblasts makes it difficult to distinguish this lesion histologically from the differentiated liposarcoma described by Kauffman and Stout and by Shuman (1961). The fact that it may recur if inadequately excised is more suggestive of a neoplasm than a developmental abnormality. However, contemporary opinion is that lipoblastomatosis is not prone to recur, whereas the welldifferentiated liposarcoma has, in the words of Kauffman and Stout, an 'inexorable tendency to recur'. Unfortunately the term 'lipoblastomatosis' is ambiguous even if this is a developmental abnormality, as the suffix 'osis' has, by usage, come to imply widespread multicentric involvement by a tumour-like process. Lipoblastomatosis may therefore be confused with the different entity 'systemic multicentric lipoblastosis' described by Goormaghtigh et al. (1936-37) and Tedeschi (1946). However, as this suffix is derived from the Greek word 'osis' (co~) meaning 'condition' (Onions, I955), there can be no objection to its use to denote a solitary condition. The terms 'thrombosis' and 'sclerosis' are examples of the use of this suffix to describe single lesions. If the lesion is in fact a neoplasm, the term 'lipoblastoma' would be preferable. Jaffe (1926) believes that tumours made up of lipoblasts should be called lipoblastomas and differentiated from liposarcoma. Although he does not describe specific cases, Jaffe states that the lipoblastoma is encapsulated, easily removed and has a regular histological structure. Cell anaplasia and atypical mitoses are absent. 'Although some observers have noted an invading growth into adjacent musculature, nothing is known about recurrence or metastases.' A further complication in terminology is that the term 'lipoblastoma' is used, particularly by Continental workers, to describe a somewhat different entity. One example is a paper by Carcassonne et al. (1964), who report a case of lipoblastoma in the mesentery. They believe that this is a tumour that spreads by diffuse infiltration; is made up of myxoid tissue and young lipoblasts and lipocytes without cellular atypism. It spreads locally and to distant sites and change to liposarcoma is possible. These authors consider that it is a turnout of intermediate malignancy between lipoma and liposarcoma. One gets the impression that their lipoblastoma probably corresponds with the differentiated liposarcoma of other workers (Kauffman & Stout, 1959; Shuman, I961). As the term 'lipoblastomatosis' has now been accepted by a number of writers to describe this specific entity, little would be gained by altering the nomenclature until such time as further evidence implicating its neoplastic nature is presented. There is sufficient evidence to warrant its consideration as an entity. The lesion is confined to infants and has a characteristically lobulated histological pattern. The lobules, which have a well-defined vascular component, consist predominantly of adult fat cells but are interspersed with numerous lipoblasts. Mitoses occur but bizarre forms are not found. Most of the reported cases have occurred in the upper pectoral and axillary regions, but Enterline's case involved the popliteal fossa and the present case occurred in the cheek. There is no sex
z78
B R I T I S H J O U R N A L OF ORAL SURGERY
predilection. Reports of its behaviour vary. Four of the seven reported cases were apparently readily excised at operation and had not recurred following review up to two and a half years post-operatively. The case of van Meurs recurred four times, but there is evidence that the lesion was maturing all the time. In one of the four cases reported by Kauffman and Stout, the lesion was not well demarcated and recurred three months after operation. The case of Enterline et al. invaded muscle deep to the lesion, but no follow-up is reported. In the present case no review was possible as the child's parents removed him from hospital (Table I). Lipomas of the oral tissues are relatively uncommon; liposarcomas are exceptionally rare (Lucas, I964). Stout (I944), who reports 4I cases of liposarcoma accumulated over a period of 37 years in the Department of Surgical Pathology, Columbia University, describes two occurring in the cheek. No unequivocal case of lipoblastomatosis of the mouth has, as far as I am aware, been previously recorded, although Ransohoff (z917) reports two cases of congenital lipoma of the cheek. One of these was in a girl of 6 months who had had a rapidly enlarging tumour of the left cheek from the time of her birth. The tumour was removed by an external approach and 'revealed a lipoma, which in places has undergone myxomatous degeneration'. The second case was a 5-year-old girl with a swelling of the left cheek which had been previously operated on at the age of I year. The tumour could not be removed in one mass but was removed piecemeal. The pathologist reported that 'for a lipoma, there was an unusual development of fibrous and lymphangiomatous tissue'. Although both these cases may be examples of lipoblastomatosis, the incomplete information, particularly in respect of the histopathology, precludes definite diagnoses. The occurrence of fat hamartomas in the cheek can be attributed to the presence of the buccal fat pad. The development of this pad has been studied by Scammon (I918-I9), who states that the formation of lobules in the pad is, in the majority of cases, completed by the end of the fifth month of intra-uterine life and differentiation of new fat cells generally by the seventh month. Lipoblastomatosis arising in the buccal fat pad therefore implies continued proliferation of fat-forming elements beyond the seventh month in utero.
SUMMARY Lipoblastomatosis is a rare developmental anomaly which is characterised by the continued proliferation of lipoblasts in the post-natal period. It is found in infants and occurs in sites of foetal fat formation. The case reported here arose in the cheek of an 18-month-old child and is believed to have developed from the buccal fat pad. It enucleated readily at operation, but it has not been possible to follow the patient's progress. Histological examination showed the typical features of a distinctly lobulated growth comprising mainly adult fat ceils but interspersed with many lipoblasts in various stages of differentiation. In each lobule there was diffuse capillary network. Mitoses were seen, but bizarre forms were not present. It is generally believed that lipoblastomatosis is of restricted growth, will
LIPOBLASTOMATOSIS
OF THE CHEEK
179
not recur i f completely excised b u t m a y recur i f cut across. I t m u s t be distinguished f r o m the well-differentiated liposarcoma which is locally invasive. T h e hypothesis that the lesion is o f a hamartomatous nature is sound and the t e r m lipoblastomatosis should be retained unless evidence of its neoplastic character is presented. ACKNOWLEDGEMENTS The author acknowledges, with sincere thanks, the assistance of Mr. M. Ulrich and Miss Denise Moore with the photomicrographs.
REFERENCES
CARCASSONNE,F., BONNEAU, H., PESCHARD,J. J. & GHIRAGOSSIAN,O. (1964). ft. int. Coll. Surg. 42, 31 I. ENTERLINE, H. T., CULBERSON, J. D., ROCHLIN, D. B. & BRADY, L. W. (196o). Cancer, 13, 932. GOORMAGHTHIGH,N., VANDERLINDEN,P. & DE PUYSSELEYR,R. (1936-47). Cancer, Brux. 13, 3. (Cited by Tedeschi, C. G., 1946.) JAFFE, R. H. (1926). Arch. Path. lab. z~led. I, 381. KAUFFMAN, SHIRLEY,L. & STOUT, A. P. (1959). Cancer, 12, 912. LUCAS, R. B. (1964). Pathology of Tumours of the Oral Tissues, p. 14o. London: Churchill. ONIONS, C. T. (1955). Shorter Oxford English Dictionary, 3rd ed., p. 1389. Oxford: Clarendon Press. RANSOHOFF,J. (1917). Ann. Surg. 65, 711. SCAMMON, R. E. (1918-19). Anat. Rec. 15, 267. SHUMAN, R. (1961). Mesenchymal turnouts. In Pathology, ed. Anderson, W. A. D., 4th ed., p. 471. St. Louis: Mosby. STOUT, A. P. (1944). Ann. Surg. 119, 86. TEDESCHI, C. G. (1946). Archs Path. 42, 32o. VAN MEURS, D. P. (1947). Br. ft. Surg. 34, 282. VELLIOS, F., BAEZ, J. & SCHUMACKER,H. B. (1958). Am. ft. Path. 34, 1149. WILLIS, R. A. (1962). The Pathology of the Tumours of Children. Pathological Monographs, II, p. ioo. Edinburgh: Oliver & Boyd.
OF THE
CHEEK
MERVYN SHEAR, M.D.S., M.C.PATH. Joint Oral Pathology Unit, University of the IVitwatersrand and South African Institute for Medical Research, Johannesburg, South Africa LIPOBLASTOMATOSIS is a rare lesion of fat cells which has not previously been recorded in the oral tissues. Its nature was first recognised by Vellios et al. (I958), who gave it its present name. Their case involved the pectoral region and axilla in a girl aged 8 months. These authors studied the embryogenesis of adipose tissue in human foetuses and found that although the formation of fat lobules appears to cease in late foetal or early post-natal life, the differentiation of individual lipoblasts may continue. In certain areas such as the axilla, mediastinum and retroperitoneum, fat cells may not attain adult form at the time of birth. They believe that lipoblastomatosis occurs when there is continued proliferation of lipoblasts and of new lobules of adipose tissue in the post-natal period. In a review of 27 fatty turnouts, Kauffman and Stout (I959) describe four cases of lipoblastomatosis, one of which was the case previously reported by Vellios et aL They emphasise the lobulated nature of these masses and state that although areas of active lipogenesis are commonly found they are potentially less dangerous than liposarcomas because of their restricted nodular growth. They do, however, point out that they may recur if inadequately excised. Of the three previously unreported cases in the series recorded by Kauffman and Stout, two occurred in males and all were noticed during the first year of life. One occurred in the neck and mediastinum, one in the buttock and one in the chest wall. Only the latter case recurred, three months after treatment. The others have been followed, with no evidence of recurrence, for two and a half years and eight months, respectively (Table I). A case occurring in the popliteal region of a Ig-month-old child is reported by Enterline et al. (196o). There was a three-month history of an enlarging TABLE I
CASES OF LIPOBLASTOMATOSIS Author(s)
Site
I. Vellios et al. 2. Kauffman and Stout 3. Kauffman and Stout 4. Kauffman and Stout 5- Enterline et aL 6. van Meurs 7. Shear
Pectoral Neck/mediastinum Buttock Chest wall
Recurrence Follow-up
Sex
Operation
F M
Dissected free Excised
No
4
No
2½ yr. 2½ yr.
6½
M
Excised
No
8 mo.
4~
F
Not well demarcated Invaded muscle Not excised Dissected free
Yes 3 mo.
4 mo.
Age Months
M
Popliteal Axilla Cheek
8
I9 F M r73
Yes × 4
20 m o .
174
B R I T I S H JOURNAL OF ORAL SURGERY
t u m o u r and at operation an encapsulated mass was found which extended into the adjacent gastrocnemius muscle. T h e t u m o u r had a lobular pattern and a well-defined lobular blood supply. It was composed o f mature fat cells with areas o f immature cells. Vellios et al. believe that the case described by van Meurs (1947) as an embryonic lipoma may have been one o f lipoblastomatosis. Van Meurs' case was one o f a fatty t u m o u r in the right axilla o f a 5-month-old girl. T h e t u m o u r recurred four times and the child had five operations between the ages o f 5 and 25 months. Histological examination at successive operations showed relatively more and more adult tissue. In the earlier specimens myxomatous tissue predominated whereas later the lesion was more lipomatous. Van Meurs felt that the t u m o u r arose from persistent embryonic adipose tissue in the interscapular area b u t remained under the influence o f factors controlling cell growth so that it was altered into an innocent tumour.
CASE R E P O R T An African child of I8 months was admitted to hospital with a mass on the mucosal surface of the cheek close to the opening of the parotid duct. The surgeon was not able to elicit accurately how long the swelling had been present nor the rapidity of growth. At operation, the tumour appeared to enucleate completely. The patient has not been seen since discharge and attempts to locate the family have been unsuccessful. P a t h o l o g y . The fixed specimen was a dark, ovoid, soft tissue mass measuring 3o× 2o× IO mm. The surface was smooth and the cut surface was darkly coloured, homogeneous, and did not resemble adult fat. Histological examination of the specimen at low magnification shows a distinctly lobulated pattern (Fig. In). On the surface there is a band of fibrinous and necrotic material enmeshed in which are numerous inflammatory cells. The interlobular septa, which are densely infiltrated with polymorphonuclear leukocytes, have a loose myxoid appearance but are irregularly and only faintly metachromatic with toluidine blue (Fig. 1a). Many bacteria can be demonstrated in the septa and in the surface tissue. At slightly higher magnification (Fig. IC) the lobules are seen to comprise mainly adult fat cells, but interspersed with these are many lipoblasts in various stages of differentiation. In each lobule there is a diffuse capillary network. Lipofuscin pigment is present at the periphery of many of the fat cells. The majority of lipoblasts are large round or ovoid cells (Fig. 2A and B) but some smaller spindle and stellate forms are seen (Fig. 2c). Their nuclei are plump, eccentric and pyknotic. Mitoses are present (Fig. 2D) but no bizarre forms are seen. Three lipoblasts in varying stages of development are illustrated in Figure 2A. At an early stage they have a granular, eosinophilic cytoplasm containing numerous small vacuoles. These vacuoles coalesce, forming a progressively larger vacuole while the granular cytoplasm is compressed to the periphery of the cell. Special stains demonstrate the presence of neutral fat in some of the lipoblasts (Fig. 2B). Lipoblasts and lipocytes are also seen in the interlobular septa (Fig. IB).
DISCUSSION I n naming this entity 'lipoblastomatosis' the implication o f Vellios and his co-workers is clearly that it is not a neoplasm but a continuation o f the normal
LIPOBLASTOMATOSIS
FIG.
OF
THE
CHEEK
IA
Distinctly lobulated pattern which is characteristic of lipoblastomatosis. H. a n d E . x4o. FIG. IB The interlobular septa have a loose myxoid appearance and contain lipoblasts and lipocytes. I n this case there is a dense inflammatory cell infiltrate. Lipofuscin pigment is present at the periphery of many of the fat cells. H. and E. x 12o. FIG. IC The lobules comprise mainly adult fat cells but many lipoblasts are interspersed. A diffuse capillary network is present in each lobule. H. and E. ×15o.
175
176
BRITISH JOURNAL OF ORAL SURGERY
process o f foetal fat development carried into post-natal life. T h e y arc supported in this opinion by K a u f f m a n and Stout, Enterline e t al. (I96O) and Willis (I962). T h e latter author believes that the lesion is in the group of adipose h a m a r t o m a and congenital liporna and catls it a 'congenital lipomatoid growth'. T h i s hypothesis is supported by three facts: the exclusive occurrence o f this lesion in infants; its location in sites of, and its histological resemblance to~ some of the stages of foetal fat formation; and the evidence provided b y van M c u r s '
~.
•
i~
B
A
FIG. 2A A number of lipoblasts are illustrated in this field. They are large ovoid to round cells with eccentric pyknotic nuclei. An early stage (A) shows the presence of numerous minute vacuoles in a granular eosinophilic cytoplasm. At B a large vacuole has formed by coalescence, and at C increase in size of the vacuole has compressed the cytoplasm to the periphery of the cell. H. and E. × 6oo. FIG. 2B Neutral fat in a lipoblast. Oil red O. x 6oo.
c FIG. 2C Spindle and stellate lipoblasts. Many polymorphonuclear leukocytes are present in this case. H. and E. × 480. FIG. 2D A lipoblast in mitosis. H. and E. × 360.
L I P O B L A S T O M A T O S I S OF THE CHEEK
177
case in which five consecutive biopsies showed progressive maturation of the adipose tissue. On the other hand, there are certain features which suggest a neoplastic character. One of the cases of Kauffman and Stout recurred after three months and the case of Enterline et al. was locally invasive. The present case enucleated readily and is distinctly lobulated, but the presence ofmyxoid tissue and numerous lipoblasts makes it difficult to distinguish this lesion histologically from the differentiated liposarcoma described by Kauffman and Stout and by Shuman (1961). The fact that it may recur if inadequately excised is more suggestive of a neoplasm than a developmental abnormality. However, contemporary opinion is that lipoblastomatosis is not prone to recur, whereas the welldifferentiated liposarcoma has, in the words of Kauffman and Stout, an 'inexorable tendency to recur'. Unfortunately the term 'lipoblastomatosis' is ambiguous even if this is a developmental abnormality, as the suffix 'osis' has, by usage, come to imply widespread multicentric involvement by a tumour-like process. Lipoblastomatosis may therefore be confused with the different entity 'systemic multicentric lipoblastosis' described by Goormaghtigh et al. (1936-37) and Tedeschi (1946). However, as this suffix is derived from the Greek word 'osis' (co~) meaning 'condition' (Onions, I955), there can be no objection to its use to denote a solitary condition. The terms 'thrombosis' and 'sclerosis' are examples of the use of this suffix to describe single lesions. If the lesion is in fact a neoplasm, the term 'lipoblastoma' would be preferable. Jaffe (1926) believes that tumours made up of lipoblasts should be called lipoblastomas and differentiated from liposarcoma. Although he does not describe specific cases, Jaffe states that the lipoblastoma is encapsulated, easily removed and has a regular histological structure. Cell anaplasia and atypical mitoses are absent. 'Although some observers have noted an invading growth into adjacent musculature, nothing is known about recurrence or metastases.' A further complication in terminology is that the term 'lipoblastoma' is used, particularly by Continental workers, to describe a somewhat different entity. One example is a paper by Carcassonne et al. (1964), who report a case of lipoblastoma in the mesentery. They believe that this is a tumour that spreads by diffuse infiltration; is made up of myxoid tissue and young lipoblasts and lipocytes without cellular atypism. It spreads locally and to distant sites and change to liposarcoma is possible. These authors consider that it is a turnout of intermediate malignancy between lipoma and liposarcoma. One gets the impression that their lipoblastoma probably corresponds with the differentiated liposarcoma of other workers (Kauffman & Stout, 1959; Shuman, I961). As the term 'lipoblastomatosis' has now been accepted by a number of writers to describe this specific entity, little would be gained by altering the nomenclature until such time as further evidence implicating its neoplastic nature is presented. There is sufficient evidence to warrant its consideration as an entity. The lesion is confined to infants and has a characteristically lobulated histological pattern. The lobules, which have a well-defined vascular component, consist predominantly of adult fat cells but are interspersed with numerous lipoblasts. Mitoses occur but bizarre forms are not found. Most of the reported cases have occurred in the upper pectoral and axillary regions, but Enterline's case involved the popliteal fossa and the present case occurred in the cheek. There is no sex
z78
B R I T I S H J O U R N A L OF ORAL SURGERY
predilection. Reports of its behaviour vary. Four of the seven reported cases were apparently readily excised at operation and had not recurred following review up to two and a half years post-operatively. The case of van Meurs recurred four times, but there is evidence that the lesion was maturing all the time. In one of the four cases reported by Kauffman and Stout, the lesion was not well demarcated and recurred three months after operation. The case of Enterline et al. invaded muscle deep to the lesion, but no follow-up is reported. In the present case no review was possible as the child's parents removed him from hospital (Table I). Lipomas of the oral tissues are relatively uncommon; liposarcomas are exceptionally rare (Lucas, I964). Stout (I944), who reports 4I cases of liposarcoma accumulated over a period of 37 years in the Department of Surgical Pathology, Columbia University, describes two occurring in the cheek. No unequivocal case of lipoblastomatosis of the mouth has, as far as I am aware, been previously recorded, although Ransohoff (z917) reports two cases of congenital lipoma of the cheek. One of these was in a girl of 6 months who had had a rapidly enlarging tumour of the left cheek from the time of her birth. The tumour was removed by an external approach and 'revealed a lipoma, which in places has undergone myxomatous degeneration'. The second case was a 5-year-old girl with a swelling of the left cheek which had been previously operated on at the age of I year. The tumour could not be removed in one mass but was removed piecemeal. The pathologist reported that 'for a lipoma, there was an unusual development of fibrous and lymphangiomatous tissue'. Although both these cases may be examples of lipoblastomatosis, the incomplete information, particularly in respect of the histopathology, precludes definite diagnoses. The occurrence of fat hamartomas in the cheek can be attributed to the presence of the buccal fat pad. The development of this pad has been studied by Scammon (I918-I9), who states that the formation of lobules in the pad is, in the majority of cases, completed by the end of the fifth month of intra-uterine life and differentiation of new fat cells generally by the seventh month. Lipoblastomatosis arising in the buccal fat pad therefore implies continued proliferation of fat-forming elements beyond the seventh month in utero.
SUMMARY Lipoblastomatosis is a rare developmental anomaly which is characterised by the continued proliferation of lipoblasts in the post-natal period. It is found in infants and occurs in sites of foetal fat formation. The case reported here arose in the cheek of an 18-month-old child and is believed to have developed from the buccal fat pad. It enucleated readily at operation, but it has not been possible to follow the patient's progress. Histological examination showed the typical features of a distinctly lobulated growth comprising mainly adult fat ceils but interspersed with many lipoblasts in various stages of differentiation. In each lobule there was diffuse capillary network. Mitoses were seen, but bizarre forms were not present. It is generally believed that lipoblastomatosis is of restricted growth, will
LIPOBLASTOMATOSIS
OF THE CHEEK
179
not recur i f completely excised b u t m a y recur i f cut across. I t m u s t be distinguished f r o m the well-differentiated liposarcoma which is locally invasive. T h e hypothesis that the lesion is o f a hamartomatous nature is sound and the t e r m lipoblastomatosis should be retained unless evidence of its neoplastic character is presented. ACKNOWLEDGEMENTS The author acknowledges, with sincere thanks, the assistance of Mr. M. Ulrich and Miss Denise Moore with the photomicrographs.
REFERENCES
CARCASSONNE,F., BONNEAU, H., PESCHARD,J. J. & GHIRAGOSSIAN,O. (1964). ft. int. Coll. Surg. 42, 31 I. ENTERLINE, H. T., CULBERSON, J. D., ROCHLIN, D. B. & BRADY, L. W. (196o). Cancer, 13, 932. GOORMAGHTHIGH,N., VANDERLINDEN,P. & DE PUYSSELEYR,R. (1936-47). Cancer, Brux. 13, 3. (Cited by Tedeschi, C. G., 1946.) JAFFE, R. H. (1926). Arch. Path. lab. z~led. I, 381. KAUFFMAN, SHIRLEY,L. & STOUT, A. P. (1959). Cancer, 12, 912. LUCAS, R. B. (1964). Pathology of Tumours of the Oral Tissues, p. 14o. London: Churchill. ONIONS, C. T. (1955). Shorter Oxford English Dictionary, 3rd ed., p. 1389. Oxford: Clarendon Press. RANSOHOFF,J. (1917). Ann. Surg. 65, 711. SCAMMON, R. E. (1918-19). Anat. Rec. 15, 267. SHUMAN, R. (1961). Mesenchymal turnouts. In Pathology, ed. Anderson, W. A. D., 4th ed., p. 471. St. Louis: Mosby. STOUT, A. P. (1944). Ann. Surg. 119, 86. TEDESCHI, C. G. (1946). Archs Path. 42, 32o. VAN MEURS, D. P. (1947). Br. ft. Surg. 34, 282. VELLIOS, F., BAEZ, J. & SCHUMACKER,H. B. (1958). Am. ft. Path. 34, 1149. WILLIS, R. A. (1962). The Pathology of the Tumours of Children. Pathological Monographs, II, p. ioo. Edinburgh: Oliver & Boyd.