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Oral spindle cell lipoma
Oral Spindle Cell Lipoma Nasser Said-Al-Naief, DDS, MS, Fazlur R. Zahurullah, MD, and James J. Sciubba, DMD, PhD Lipoma is an uncommon benign, oral, soft-tissue neoplasm commonly found on the buccal mucosa. It is predominantly composed of mature fat with or without other mesenchymal tissue elements, showing a variety of histologic subtypes, one of which is the rare “spindle cell variant” with only nine previously reported cases in the English literature. In this report, we review clinical and histomorphologic data of 164 cases of oral lipomas retrieved from the files of Long Island Jewish Medical Center, Department of Dental Medicine (New Hyde Park, NY). Of these, only two cases were diagnosed as the spindle cell variant, further confirming the rarity of this histologic subtype. A review of oral lipoma with particular reference to the spindle cell variant is also presented. Ann Diagn Pathol 5: 207-215, 2001. Copyright © 2001 by W.B. Saunders Company Index Words: Oral, lipoma, spindle cell lipoma, review
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OLITARY lipomas are the most common soft tissue tumors, benign or malignant. While commonly found on the upper back, shoulder, abdomen, and head and neck, with predilection for the latter,1 they are uncommon intraorally.1-3 Lipomas are composed entirely of mature fat cells with or without other mesenchymal tissue elements, showing a variety of histologic subtypes. These include the common (ordinary) lipoma, fibrolipoma, myxoid lipoma, angiolipoma, myolipoma, and spindle cell lipoma.1,3,4 The latter subtype is rarely encountered intraorally5-12 and is generally benign, but may occasionally present a diagnostic challenge and potential pitfall which can mistakenly lead to overtreatment.11,13 A total of 11 cases of intraoral spindle cell lipoma have been described. These include two cases retrieved from our data at the
From the Department of Pathology, the University of Alabama at Birmingham; the Department of Otolaryngology, Rockford Health System, Rockford, IL; and the Department of Otolaryngology Head and Neck Surgery, Division of Dental & Oral Medicine, Johns Hopkins University, Baltimore, MD. This study was performed on cases retrieved from Long Island Jewish Medical Center, Departments of Dental Medicine & Otolaryngology Head and Neck Surgery, New Hyde Park, NY. Address reprint requests to Nasser Said-Al-Naief, DDS, MS, University of Alabama at Birmingham, Department of Pathology, SDB 81, 1530 3rd Ave South, Birmingham, AL 35294-0007. Copyright © 2001 by W.B. Saunders Company 1092-9134/01/0504-0003$35.00/0 doi:10.1053/adpa.2001.26973
Long Island Jewish Medical Center (New Hyde Park, NY). In this study, we confirm the rarity of intraoral spindle cell lipoma. Materials and Methods One hundred forty six cases of intraoral lipoma were retrieved from the files of the Department of Dental Medicine at Long Island Jewish Medical Center and were analyzed. Sixty-nine cases (47.26%) occurred in females and 77 cases (52.73%) involved males. Histologically, the diagnosis of ordinary lipoma dominated, comprising 56.84% of all cases (83 cases), followed by fibrolipoma, 34.24% (50 cases), myxoid lipoma 5.47% (8 cases), and angiolipoma 2.05% (3 cases), and only 1.36% (2 cases) belonged to the spindle cell variant. Table 1 shows the distribution of all cases according to histologic type in various oral mucosal sites. The majority of cases (49 cases, 33.5%) involved the buccal mucosa, followed by the lower lip (30 cases, 20.5%) and mucobuccal folds (14 cases, 9.5%). The lateral tongue, dorsum of the tongue, and retromolar pad area were each involved with nine cases (6.16%). Eight lipomas (5.4%) occurred on the floor of the mouth and six cases (4.1%) were located on the retromandibular raphae. The hard and soft palate were involved with four cases (2.7%), while only one case (0.68%) was found on the upper lip. The lesions varied in size ranging from 0.3 to 2.2 cm in greatest dimensions. All lesions were treated with surgical excision without recurrence, with the exception of an ordinary lipoma that involved the buccal mucosa. This led to speculation that the recurrence was caused by incomplete excision at first attempt, rather than the growth of the lesion.
Annals of Diagnostic Pathology, Vol 5, No 4 (August), 2001: pp 207-215
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Said-Al-Naief, Zahurullah, and Sciubba Table 1. Clinicopathologic Features of 146 Oral Lipomas Histomorphologic Type Location
Ordinary Lipoma
Fibrolipoma
Myxoid Lipoma
Angiolipoma
SpindleCell Lipoma
Buccal mucosa Mucobuccal fold Floor of mouth Lateral tongue Dorsal tongue Ventral tongue Lower lip Upper lip Hard palate Soft palate Retromolar pad Pterygomandibular raphae Total no. of cases per site
25 10 5 6 5 3 18 0 2 2 5 2 83
22 3 3 0 3 0 7 1 2 2 3 4 50
0 1 0 1 1 0 4 0 0 0 1 0 8
2 0 0 0 0 0 1 0 0 0 0 0 3
0 0 0 2 0 0 0 0 0 0 0 0 2
Pathology All lesions, regardless of histologic subtype, were characterized by the presence of mature uniformappearing adipocytes. Encapsulation or clear distinction from the surrounding connective tissue and the presence of variable number of mast cells was uniformly seen in all biopsies. The majority of cases in the present review consisted of ordinary lipoma showing mature adipocytes, slightly variable in size, with each containing a single nucleus flattened against the cell periphery. Scattered vascularity can be seen interspersed within the adipocytes. The lesions were well circumscribed and were oc-
casionally surrounded by a thin fibrous connective tissue capsule. A hint of lobular pattern was seen, especially prominent in larger lesions (Fig 1). Other lesions showed a similar pattern to ordinary lipoma with the addition of dense fibrocollagenous connective tissue bands with or without hyalinization, intercepting between the adipocytes defining the histologic pattern characteristic of fibrolipoma. Aggregates of chronic inflammatory cells were occasionally observed (Fig 2). A myxoid background with sparse vascularity partially replaced the fatty tissue in other lesions defining myxoid lipoma (Fig 3).
Figure 1. Histologic findings of ordinary lipoma showing mature, tightly packed adipocytes with few scattered vascular spaces in between (arrows). (Hematoxylin-eosin stain. Magnification ⫻ 200.) Insert: A higher magnification of the lesion showing mature adipocytes, each containing a single nucleus, flattened against the periphery of the cell. (Magnification ⫻ 400.)
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Figure 2. A representative section from a fibrolipoma shows fibrocollagenous fibrous connective tissue background (arrows) partially replacing and intersecting between the fatty tissue. The lesion is surrounded by a well-formed fibrous connective tissue capsule (c). (Hematoxylin-eosin stain. Magnification ⫻ 200.)
Other examples showed numerous, small, vascular channels interspersed among the adipocytes with scattered, but focal and mild, perivascular fibrosis showing features of angiolipoma (Fig 4). Spindle cell lipomas displayed an admixture of mature fat cells and uniform spindle cells in a fibrocollagenous background. Occasionally, the cellular components were juxtaposed with a myxoid background. Each spindle cell had single elongated nucleus with or without cytoplasmic vacuolization (Fig 5). Discussion 2
Roux first described oral lipoma in 1848, where it was referred to as yellow epulis.3 They are more common in males, as compared to other body sites where older females are more frequently affected4 and are otherwise asymptomatic unless there is
nerve compression or expansion into surrounding areas.4 Approximately 13% of lipomas are found in the head and neck area,4 including the parotids,14-17 oral mucosa,18-22 pharynx,23-25 and larynx.23,24 Enzinger and Harvey26 reported the first series of spindle cell lipomas. They described the entity as a painless and slow-growing nodule that almost exclusively involved the shoulder and posterior neck. They also noted that it predominantly involved men (94%) between 45 and 70 years of age (mean, 56 years). Subsequent reports confirmed these findings.27,28 All of the cases in the original series behaved in a benign fashion with local excision adequate for treatment. Spindle cell lipomas account for 1.5% of fatty neoplasms and are outnumbered by conventional lipomas by a factor of 60 to 1.7,10 The differential diagnosis of a mass with these
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Figure 3. A predominantly myxoid background was seen in myxoid lipoma, which may mimic or be confused with myxoid liposarcoma. Mature adipocytes are seen at the edges of the section. Numerous aggregates of mast cells (arrows) are also scattered throughout the section. (Hematoxylin-eosin stain. Magnification ⫻ 400.)
characteristics includes lipoma and fibroma, and may include salivary gland lesions (neoplasms and mucoceles) and fibroepithelial polyps. The differential also may include benign nerve sheath tumors if the lesion occurs in the setting of a mass that involves tissues deep to an intact mucosal surface.5-7 Herniated buccal fat pad, also referred to as “traumatic pseudolipoma,” must always be included at the top of the differential list of oral lipoma. Herniated buccal fat pad develops subsequent to acute trauma bilaterally because of herniation of a portion of the buccal fat pad and may assume a sessile or pedunculated appearance. It is common in infants, but also may occur in adults (especially overweight individuals).3,29-32 History of trauma is consistently present in herniated buccal fat pad, thus the name “traumatic pseudolipoma,” as proposed by most investigators.30-32 On occasion, it may not be possible to distinguish herniated
buccal fat pad from a true lipoma if the former become epithelialized.32 With the exception of a malignant salivary gland tumor, appropriate management for each of these entities may include excisional biopsy as a diagnostic and therapeutic maneuver. Histologically, oral lipomas are composed of mature fat cells arranged in lobular fashion simulating extraoral subcutaneous lipoma and the normal surrounding fat. Typically, they are encapsulated or well circumscribed with rare exceptions.1,28 Cytologically, the nuclei of the adipocytes are fairly uniform. Occasionally, the histologic features of a lipoma are altered by the presence of other mesenchymal components.1-4,33 These variants include angiolipoma, myolipoma, angiomyolipoma, myelolipoma, chondroid lipoma, pleomorphic lipoma, benign lipoblastoma, and spindle cell lipoma.1 Spindle cell lipoma is histologically characterized
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Figure 4. (Top) Medium-power view of angiolipoma showing multiple variably sized blood vessels scattered throughout the lesion. (Hematoxylineosin stain. Magnification ⫻ 200.) (Bottom) A higher magnification of the same lesion showing perivascular fibrosis (arrows) present focally within the lesion. (Hematoxylin-eosin stain. Magnification ⫻ 400.)
by the presence of an admixture of mature fat cells, uniform spindle cells, and short bundles of collagen associated with the spindle cells.1,27,28 The extent of replacement of fat cells by spindle cells varies from one case to another. Spindle cells are characterized by uniformity, having a single elongated nucleus, bipolar cytoplasmic processes, and typically containing one or two vacuoles within the cytoplasm.1,28 Adipocytes are univacuolated, mostly uniform cells that contain small peripheral nu-
clei.1,28 No lipoblastic activity is observed in spindle cell lipoma, and mitotic figures are seldom seen.1,27 Variably sized collagen fibers are haphazardly distributed.1,28 Occasionally, the cellular components of the tumor may be present within a myxoid matrix that is often distinct enough to separate the spindle cells from the surrounding adipocytes.28 In this matrix, mast cells are common and lymphocytes are infrequently seen. Typically, vascularity is inconspicuous.1,28
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Figure 5. (Top) A low-power photomicrograph of spindle cell lipoma showing an admixture of fat pad fascicles of bland and uniform spindle cells (open arrow). The fatty component was supported in part by looser myxoid areas (solid arrow). (Hematoxylin-eosin stain. Magnification ⫻ 200.) (Center) A higher power photomicrograph shows the benign and mature fatty component in the present lesion. (Hematoxylin-eosin stain. Magnification ⫻ 400.) (Bottom) Bland-looking spindle cells in a background of thick wiry bundles of collagen are shown. (Hematoxylineosin stain. Magnification ⫻ 400.)
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Table 2. Summary of Findings in Seven Cases of Spindle Cell Lipoma Reported in the Oral Cavity
Case
Study
Location
Age
Sex
1
McDaniel et al5
33
F
2 3
McDaniel et al5 Christopoulos et al9 Levy8
Anterior floor of mouth Tongue Right hard palate Anterior floor of mouth
52 58
4
5
Size (cm)
Characteristics
B
1 ⫻ 1 ⫻ 0.8
M M
NA W
NA 2⫻2⫻2
74
F
W
4.3 ⫻ 3.5 ⫻ 1.5
Dorsum of tongue Right buccal mucosa Left buccal mucosa Anterior and left lateral tongue
68
F
W
1.5 ⫻ 1.3 ⫻ 1
23
M
NA
5 ⫻ 2.5 ⫻ 1.5
55
M
NA
4.0 ⫻ 2.0 ⫻ 1.2
42
F
NA
Right buccal mucosa Said-Al-Naief Lateral et al (current) tongue Said-Al-Naief Lateral et al (current) tongue
75
M
NA
66
M
W
3 ⫻ 2.5 ⫻ 1.7
53
F
B
0.6 ⫻ 0.6 ⫻ 0.7
Firm, rubbery, nontender, intact surface mucosa NA Rubbery, nontender, intact surface mucosa Soft, nontender, intact surface mucosa, displaced tongue superiorly Pedunculated, intact surface mucosa Painless, slow-growing, intact surface mucosa Bilobular, superficial, surface mucosa intact Gradually enlarging, painless tongue swelling present for many years Painless, mobile mass of 4-months duration Rubbery, nontender, intact surface mucosa Sessile, round soft-tissue lesion, covered by nonulcerated, normalcolor mucosa. Clinical impression: granular cell tumor
6
Lombardi and Odell7 Khoo and Lian6
7
Tosios et al10
8
Dutt et al11
9
Piattelli et al12
10 11
Race
3⫻2⫻1
2 cm
Post Excision Follow-Up Period
Condition at Follow-Up
NA
NA
8 yrs 2 yrs
NED NED
NA
NA
NA
NA
3 yrs
NED
2 yrs
NED
NA
NA
NA
NA
1 yr
NED
3 yrs
NED
Abbreviations: NA, data not available; NED, no evidence of disease; W, white; B, black.
Immunohistochemical analysis of spindle cell lipoma shows that the spindle cells do not exhibit immunoreactivity with antimonocyte/macrophage antibodies (MAC-387), fibronectin, laminin, factor VIII, cytokeratin, or type IV collagen,34 but react positively to vimentin and CD34.35,36 Anti–S-100 protein antibodies do not stain the spindle cells, but do stain the adipocytes.27,34-36 The histologic differential diagnosis of spindle cell lipoma and lipomas with prominent myxoid component also should include the myxoid and fibrosing subtypes of liposarcoma, lipoblastomatosis (fetal lipoma), and myxoma.13,37 Liposarcoma merits special mention, in that it is the most easily mistaken diagnosis for spindle cell lipoma. Spindle cell lipoma is separated from this and other entities on the differential list on the basis of its unique
features. These features include its well-defined nature, great uniformity of proliferating spindle cells, absence of lipoblasts, presence of mature, thick, and regular collagen within a mucoid matrix, superficial location of the lesion, and the characteristic age prevalence.1,9,10,12 The absence of lipoblasts, sparse vascularity, and presence of focal rather than diffuse myxoid change also may be of aid in distinguishing lipoma with myxoid change from myxoid liposarcoma,4 which can have very significant prognostic implications as well as an effect on therapeutic options. A review of the English literature reveals nine previously reported cases of spindle cell lipoma in the oral cavity.5-12 Significant features of these cases, along with two additional cases retrieved from our files, are summarized in Table 2. Classic
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clinical presentation included a painless, slow-growing, rubbery, submucosal mass with an intact overlying mucosa. Of the 11 cases, six were in men, and the age ranged from 23 to 74 years. Race data were only available in five patients (four whites and one black). Average size of the excised mass was approximately 3 ⫻ 2 ⫻ 1.5 cm. Postexcision follow-up data were available for six cases and have clearly shown no recurrences (follow-up period ranged from 1 to 8 years.) Conclusion Spindle cell lipoma in the oral cavity is a benign entity. Analysis of the reported cases does not suggest any strong sex or race predilection. Age at presentation varies widely, and can be seen mostly in adults of any age. The presence of a painless, slow growing, rubbery, submucosal mass with intact overlying mucosa should alert the clinician to consider this entity in the differential diagnosis. The diagnosis of spindle cell lipoma can often be made with observation of key histologic features after routine hematoxylin-eosin staining. Special effort must be made to differentiate spindle cell lipoma from more aggressive entities requiring more radical treatment. Treatment for spindle cell lipoma involves simple excision, and has not been shown to lead to recurrence. References 1. Enzinger FM, Weiss SW: Soft Tissue Tumors (ed 3). St Louis, MO, Mosby Year Book, 1995 2. Roux M: On exostoses: Their character. Am J Dent Sci 1848;9:133-134 3. Bouquot J, Nikai H: Lesions of the oral cavity, in Gnepp DR: Diagnostic Surgical Pathology of the Head and Neck. Philadelphia, PA, Saunders, 2000, pp 141–238 4. Barnes L: Tumors and tumor like lesions of the soft tissues, in Barnes L (ed): Surgical Pathology of the Head and Neck. New York, NY, Marcel Dekker, 1985, pp 749-755 5. McDaniel RK, Newland JR, Chiles DG: Intraoral spindle cell lipoma: Case report with correlated light and electron microscopy. Oral Surg Oral Med Oral Pathol 1984;57:52-57 6. Khoo SP, Lian CB: Intraoral spindle-cell lipoma: Report of a case and literature review. Ann Dent 1995;54:53-55 7. Lombardi T, Odell EW: Spindle cell lipoma of the oral cavity: Report of a case. J Oral Pathol Med 1984;23:237-239 8. Levy FE: Goding spindle cell lipoma: An unusual oral presentation. Otolaryngol Head Neck Surg 1989;101:601-603 9. Christopoulos P, Nicolatou O, Patrikiou A: Oral spindle cell lipoma. Report of a case. Int J Oral Maxillofac Surg 1989; 8:208-209
10. Tosios K, Papanicolaou SI, Kapranos N, et al: Spindle cell lipoma of the oral cavity. Int J Oral Maxillofac Surg 1995;24:363364 11. Dutt SN, East DM, Saleem Y, et al: Spindle cell variant of intralingual lipoma. Report of a case with literature review. J Laryngol Otol 1999;113:587-589 12. Piattelli A, Fioroni M, Rubini C: Spindle cell lipoma of the oral cavity: Report of a case. J Oral Maxillofac Surg 1999;57:624625 13. Gorelking L, Conrad-England R: Spindle cell lipoma: A benign lipoma variant with potential hazards of diagnostic misinterpretation. South Med J 1978;71:1163-1164 14. Baker SE, Jensen JL, Correll RW: Lipomas of the parotid gland. Oral Surg Oral Med Oral Pathol 1981;52:167-170 15. Cowdin JT, Dew JH: Fatty infiltration of parotid glands: Report of a case. Arch Surg 1958;76:525-526 16. Janecka IP, Conley J, Perzin KH, et al: Lipomas presenting as parotid tumors. Laryngoscope 1977;87:1007-1010 17. Walts AE, Perzik SL: Lipomatous lesions of the parotid area. Arch Otolaryngol 1976;102:230-232 18. Greer RO, Richardson JF: The nature of lipomas and their significance in the oral cavity: Review and report of cases. Oral Surg 1973;36:551-557 19. Hatziotis JC: Lipoma of the oral cavity. Oral Surg 1971; 31:511-524 20. Seldin HM, Seldin SD, Rakower W, et al: Lipomas of the oral cavity: Report of 26 cases. J Oral Surg 1967;25:270-274 21. Lekkas C, Van Hoof R: Lipoma of the tongue. Oral Surg 1979;48:214-215 22. Pisanty S: Bilateral lipomas of the tongue. Oral Surg 1976;42:451-453 23. Putney FJ, Fry KE: Retropharyngeal lipoma. J Otol Rhinol Laryngol 1965;74:967-972 24. Yonus M: Retropharyngeal lipoma. J Laryngol Otol 1980; 94:321-325 25. Mannson I, Wilske J, Kindblom LG: Lipoma of the hypopharynx: A case report and review of literature. J Laryngol Otol 1978;92:1037-1043 26. Enzinger FM, Harvey DA: Spindle cell lipoma. Cancer 1975;36:1852-1859 27. Fletcher CD, Martin-Bates E: Spindle cell lipoma: A clinicopathological study with some original observations. Histopathology 1987;11:803-817 28. Angervall L, Dahl I, Kindblom LG, et al: Spindle cell lipoma. Acta Pathol Microbiol Scand [A] 1976;84:477-487 29. Clawson JR, Kline KK, Armbrecht EC: Trauma induced avulsion of the buccal fat pad into the mouth. Report of a case. J Oral Surg 1968;26:546-547 30. Brooke RI: Traumatic herniation of buccal pad of fat (traumatic pseudolipoma). A review. Oral Surg Oral Med Oral Pathol 1978;45:689-691 31. Berk CW, Gibson WS Jr: Pathologic quiz case 1. Traumatic herniated gangrenous buccal fat pad (traumatic pseudolipoma). Arch Otolaryngol Head Neck Surg 1994;120:340-342 32. Brooke RI, MacGregor AJ: Traumatic pseudolipoma of the buccal mucosa. Oral Surg Oral Med Oral Pathol 1969;28: 223-225 33. Neville B, Damm D, Allen C, et al: Soft tissue tumors, in: Textbook of Oral and Maxillofacial Pathology. Philadelphia, PA, Saunders, 1995, pp 362-415 34. Beham A, Schmid C, Hodl S, et al: Spindle cell and
Oral Spindle Cell Lipoma pleomorphic lipoma: An immunohistochemical study and histogenetic analysis. J Pathol 1989;158:219-222 35. Laskin WB, Fetsch JF, Mostofi FK: Angiomyofibroblastoma like tumor of the male genital tract: Analysis of 11 cases with comparison to female angiomyofibroblastoma and spindle cell lipoma. Am J Surg Path 1998;22:6-16
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36. Mulvany NJ, Silvester AC, Collins JP: Spindle cell lipoma of the breast. Pathology 1999;31:288-291 37. Suster S, Fisher C, Moran CA: Dendritic fibromyxolipoma: Clinicopathologic study of a distinctive benign soft tissue lesion that may be mistaken for a sarcoma. Ann Diagn Pathol 1998;2:111-120
S
OLITARY lipomas are the most common soft tissue tumors, benign or malignant. While commonly found on the upper back, shoulder, abdomen, and head and neck, with predilection for the latter,1 they are uncommon intraorally.1-3 Lipomas are composed entirely of mature fat cells with or without other mesenchymal tissue elements, showing a variety of histologic subtypes. These include the common (ordinary) lipoma, fibrolipoma, myxoid lipoma, angiolipoma, myolipoma, and spindle cell lipoma.1,3,4 The latter subtype is rarely encountered intraorally5-12 and is generally benign, but may occasionally present a diagnostic challenge and potential pitfall which can mistakenly lead to overtreatment.11,13 A total of 11 cases of intraoral spindle cell lipoma have been described. These include two cases retrieved from our data at the
From the Department of Pathology, the University of Alabama at Birmingham; the Department of Otolaryngology, Rockford Health System, Rockford, IL; and the Department of Otolaryngology Head and Neck Surgery, Division of Dental & Oral Medicine, Johns Hopkins University, Baltimore, MD. This study was performed on cases retrieved from Long Island Jewish Medical Center, Departments of Dental Medicine & Otolaryngology Head and Neck Surgery, New Hyde Park, NY. Address reprint requests to Nasser Said-Al-Naief, DDS, MS, University of Alabama at Birmingham, Department of Pathology, SDB 81, 1530 3rd Ave South, Birmingham, AL 35294-0007. Copyright © 2001 by W.B. Saunders Company 1092-9134/01/0504-0003$35.00/0 doi:10.1053/adpa.2001.26973
Long Island Jewish Medical Center (New Hyde Park, NY). In this study, we confirm the rarity of intraoral spindle cell lipoma. Materials and Methods One hundred forty six cases of intraoral lipoma were retrieved from the files of the Department of Dental Medicine at Long Island Jewish Medical Center and were analyzed. Sixty-nine cases (47.26%) occurred in females and 77 cases (52.73%) involved males. Histologically, the diagnosis of ordinary lipoma dominated, comprising 56.84% of all cases (83 cases), followed by fibrolipoma, 34.24% (50 cases), myxoid lipoma 5.47% (8 cases), and angiolipoma 2.05% (3 cases), and only 1.36% (2 cases) belonged to the spindle cell variant. Table 1 shows the distribution of all cases according to histologic type in various oral mucosal sites. The majority of cases (49 cases, 33.5%) involved the buccal mucosa, followed by the lower lip (30 cases, 20.5%) and mucobuccal folds (14 cases, 9.5%). The lateral tongue, dorsum of the tongue, and retromolar pad area were each involved with nine cases (6.16%). Eight lipomas (5.4%) occurred on the floor of the mouth and six cases (4.1%) were located on the retromandibular raphae. The hard and soft palate were involved with four cases (2.7%), while only one case (0.68%) was found on the upper lip. The lesions varied in size ranging from 0.3 to 2.2 cm in greatest dimensions. All lesions were treated with surgical excision without recurrence, with the exception of an ordinary lipoma that involved the buccal mucosa. This led to speculation that the recurrence was caused by incomplete excision at first attempt, rather than the growth of the lesion.
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Said-Al-Naief, Zahurullah, and Sciubba Table 1. Clinicopathologic Features of 146 Oral Lipomas Histomorphologic Type Location
Ordinary Lipoma
Fibrolipoma
Myxoid Lipoma
Angiolipoma
SpindleCell Lipoma
Buccal mucosa Mucobuccal fold Floor of mouth Lateral tongue Dorsal tongue Ventral tongue Lower lip Upper lip Hard palate Soft palate Retromolar pad Pterygomandibular raphae Total no. of cases per site
25 10 5 6 5 3 18 0 2 2 5 2 83
22 3 3 0 3 0 7 1 2 2 3 4 50
0 1 0 1 1 0 4 0 0 0 1 0 8
2 0 0 0 0 0 1 0 0 0 0 0 3
0 0 0 2 0 0 0 0 0 0 0 0 2
Pathology All lesions, regardless of histologic subtype, were characterized by the presence of mature uniformappearing adipocytes. Encapsulation or clear distinction from the surrounding connective tissue and the presence of variable number of mast cells was uniformly seen in all biopsies. The majority of cases in the present review consisted of ordinary lipoma showing mature adipocytes, slightly variable in size, with each containing a single nucleus flattened against the cell periphery. Scattered vascularity can be seen interspersed within the adipocytes. The lesions were well circumscribed and were oc-
casionally surrounded by a thin fibrous connective tissue capsule. A hint of lobular pattern was seen, especially prominent in larger lesions (Fig 1). Other lesions showed a similar pattern to ordinary lipoma with the addition of dense fibrocollagenous connective tissue bands with or without hyalinization, intercepting between the adipocytes defining the histologic pattern characteristic of fibrolipoma. Aggregates of chronic inflammatory cells were occasionally observed (Fig 2). A myxoid background with sparse vascularity partially replaced the fatty tissue in other lesions defining myxoid lipoma (Fig 3).
Figure 1. Histologic findings of ordinary lipoma showing mature, tightly packed adipocytes with few scattered vascular spaces in between (arrows). (Hematoxylin-eosin stain. Magnification ⫻ 200.) Insert: A higher magnification of the lesion showing mature adipocytes, each containing a single nucleus, flattened against the periphery of the cell. (Magnification ⫻ 400.)
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Figure 2. A representative section from a fibrolipoma shows fibrocollagenous fibrous connective tissue background (arrows) partially replacing and intersecting between the fatty tissue. The lesion is surrounded by a well-formed fibrous connective tissue capsule (c). (Hematoxylin-eosin stain. Magnification ⫻ 200.)
Other examples showed numerous, small, vascular channels interspersed among the adipocytes with scattered, but focal and mild, perivascular fibrosis showing features of angiolipoma (Fig 4). Spindle cell lipomas displayed an admixture of mature fat cells and uniform spindle cells in a fibrocollagenous background. Occasionally, the cellular components were juxtaposed with a myxoid background. Each spindle cell had single elongated nucleus with or without cytoplasmic vacuolization (Fig 5). Discussion 2
Roux first described oral lipoma in 1848, where it was referred to as yellow epulis.3 They are more common in males, as compared to other body sites where older females are more frequently affected4 and are otherwise asymptomatic unless there is
nerve compression or expansion into surrounding areas.4 Approximately 13% of lipomas are found in the head and neck area,4 including the parotids,14-17 oral mucosa,18-22 pharynx,23-25 and larynx.23,24 Enzinger and Harvey26 reported the first series of spindle cell lipomas. They described the entity as a painless and slow-growing nodule that almost exclusively involved the shoulder and posterior neck. They also noted that it predominantly involved men (94%) between 45 and 70 years of age (mean, 56 years). Subsequent reports confirmed these findings.27,28 All of the cases in the original series behaved in a benign fashion with local excision adequate for treatment. Spindle cell lipomas account for 1.5% of fatty neoplasms and are outnumbered by conventional lipomas by a factor of 60 to 1.7,10 The differential diagnosis of a mass with these
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Figure 3. A predominantly myxoid background was seen in myxoid lipoma, which may mimic or be confused with myxoid liposarcoma. Mature adipocytes are seen at the edges of the section. Numerous aggregates of mast cells (arrows) are also scattered throughout the section. (Hematoxylin-eosin stain. Magnification ⫻ 400.)
characteristics includes lipoma and fibroma, and may include salivary gland lesions (neoplasms and mucoceles) and fibroepithelial polyps. The differential also may include benign nerve sheath tumors if the lesion occurs in the setting of a mass that involves tissues deep to an intact mucosal surface.5-7 Herniated buccal fat pad, also referred to as “traumatic pseudolipoma,” must always be included at the top of the differential list of oral lipoma. Herniated buccal fat pad develops subsequent to acute trauma bilaterally because of herniation of a portion of the buccal fat pad and may assume a sessile or pedunculated appearance. It is common in infants, but also may occur in adults (especially overweight individuals).3,29-32 History of trauma is consistently present in herniated buccal fat pad, thus the name “traumatic pseudolipoma,” as proposed by most investigators.30-32 On occasion, it may not be possible to distinguish herniated
buccal fat pad from a true lipoma if the former become epithelialized.32 With the exception of a malignant salivary gland tumor, appropriate management for each of these entities may include excisional biopsy as a diagnostic and therapeutic maneuver. Histologically, oral lipomas are composed of mature fat cells arranged in lobular fashion simulating extraoral subcutaneous lipoma and the normal surrounding fat. Typically, they are encapsulated or well circumscribed with rare exceptions.1,28 Cytologically, the nuclei of the adipocytes are fairly uniform. Occasionally, the histologic features of a lipoma are altered by the presence of other mesenchymal components.1-4,33 These variants include angiolipoma, myolipoma, angiomyolipoma, myelolipoma, chondroid lipoma, pleomorphic lipoma, benign lipoblastoma, and spindle cell lipoma.1 Spindle cell lipoma is histologically characterized
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Figure 4. (Top) Medium-power view of angiolipoma showing multiple variably sized blood vessels scattered throughout the lesion. (Hematoxylineosin stain. Magnification ⫻ 200.) (Bottom) A higher magnification of the same lesion showing perivascular fibrosis (arrows) present focally within the lesion. (Hematoxylin-eosin stain. Magnification ⫻ 400.)
by the presence of an admixture of mature fat cells, uniform spindle cells, and short bundles of collagen associated with the spindle cells.1,27,28 The extent of replacement of fat cells by spindle cells varies from one case to another. Spindle cells are characterized by uniformity, having a single elongated nucleus, bipolar cytoplasmic processes, and typically containing one or two vacuoles within the cytoplasm.1,28 Adipocytes are univacuolated, mostly uniform cells that contain small peripheral nu-
clei.1,28 No lipoblastic activity is observed in spindle cell lipoma, and mitotic figures are seldom seen.1,27 Variably sized collagen fibers are haphazardly distributed.1,28 Occasionally, the cellular components of the tumor may be present within a myxoid matrix that is often distinct enough to separate the spindle cells from the surrounding adipocytes.28 In this matrix, mast cells are common and lymphocytes are infrequently seen. Typically, vascularity is inconspicuous.1,28
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Figure 5. (Top) A low-power photomicrograph of spindle cell lipoma showing an admixture of fat pad fascicles of bland and uniform spindle cells (open arrow). The fatty component was supported in part by looser myxoid areas (solid arrow). (Hematoxylin-eosin stain. Magnification ⫻ 200.) (Center) A higher power photomicrograph shows the benign and mature fatty component in the present lesion. (Hematoxylin-eosin stain. Magnification ⫻ 400.) (Bottom) Bland-looking spindle cells in a background of thick wiry bundles of collagen are shown. (Hematoxylineosin stain. Magnification ⫻ 400.)
Oral Spindle Cell Lipoma
213
Table 2. Summary of Findings in Seven Cases of Spindle Cell Lipoma Reported in the Oral Cavity
Case
Study
Location
Age
Sex
1
McDaniel et al5
33
F
2 3
McDaniel et al5 Christopoulos et al9 Levy8
Anterior floor of mouth Tongue Right hard palate Anterior floor of mouth
52 58
4
5
Size (cm)
Characteristics
B
1 ⫻ 1 ⫻ 0.8
M M
NA W
NA 2⫻2⫻2
74
F
W
4.3 ⫻ 3.5 ⫻ 1.5
Dorsum of tongue Right buccal mucosa Left buccal mucosa Anterior and left lateral tongue
68
F
W
1.5 ⫻ 1.3 ⫻ 1
23
M
NA
5 ⫻ 2.5 ⫻ 1.5
55
M
NA
4.0 ⫻ 2.0 ⫻ 1.2
42
F
NA
Right buccal mucosa Said-Al-Naief Lateral et al (current) tongue Said-Al-Naief Lateral et al (current) tongue
75
M
NA
66
M
W
3 ⫻ 2.5 ⫻ 1.7
53
F
B
0.6 ⫻ 0.6 ⫻ 0.7
Firm, rubbery, nontender, intact surface mucosa NA Rubbery, nontender, intact surface mucosa Soft, nontender, intact surface mucosa, displaced tongue superiorly Pedunculated, intact surface mucosa Painless, slow-growing, intact surface mucosa Bilobular, superficial, surface mucosa intact Gradually enlarging, painless tongue swelling present for many years Painless, mobile mass of 4-months duration Rubbery, nontender, intact surface mucosa Sessile, round soft-tissue lesion, covered by nonulcerated, normalcolor mucosa. Clinical impression: granular cell tumor
6
Lombardi and Odell7 Khoo and Lian6
7
Tosios et al10
8
Dutt et al11
9
Piattelli et al12
10 11
Race
3⫻2⫻1
2 cm
Post Excision Follow-Up Period
Condition at Follow-Up
NA
NA
8 yrs 2 yrs
NED NED
NA
NA
NA
NA
3 yrs
NED
2 yrs
NED
NA
NA
NA
NA
1 yr
NED
3 yrs
NED
Abbreviations: NA, data not available; NED, no evidence of disease; W, white; B, black.
Immunohistochemical analysis of spindle cell lipoma shows that the spindle cells do not exhibit immunoreactivity with antimonocyte/macrophage antibodies (MAC-387), fibronectin, laminin, factor VIII, cytokeratin, or type IV collagen,34 but react positively to vimentin and CD34.35,36 Anti–S-100 protein antibodies do not stain the spindle cells, but do stain the adipocytes.27,34-36 The histologic differential diagnosis of spindle cell lipoma and lipomas with prominent myxoid component also should include the myxoid and fibrosing subtypes of liposarcoma, lipoblastomatosis (fetal lipoma), and myxoma.13,37 Liposarcoma merits special mention, in that it is the most easily mistaken diagnosis for spindle cell lipoma. Spindle cell lipoma is separated from this and other entities on the differential list on the basis of its unique
features. These features include its well-defined nature, great uniformity of proliferating spindle cells, absence of lipoblasts, presence of mature, thick, and regular collagen within a mucoid matrix, superficial location of the lesion, and the characteristic age prevalence.1,9,10,12 The absence of lipoblasts, sparse vascularity, and presence of focal rather than diffuse myxoid change also may be of aid in distinguishing lipoma with myxoid change from myxoid liposarcoma,4 which can have very significant prognostic implications as well as an effect on therapeutic options. A review of the English literature reveals nine previously reported cases of spindle cell lipoma in the oral cavity.5-12 Significant features of these cases, along with two additional cases retrieved from our files, are summarized in Table 2. Classic
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Said-Al-Naief, Zahurullah, and Sciubba
clinical presentation included a painless, slow-growing, rubbery, submucosal mass with an intact overlying mucosa. Of the 11 cases, six were in men, and the age ranged from 23 to 74 years. Race data were only available in five patients (four whites and one black). Average size of the excised mass was approximately 3 ⫻ 2 ⫻ 1.5 cm. Postexcision follow-up data were available for six cases and have clearly shown no recurrences (follow-up period ranged from 1 to 8 years.) Conclusion Spindle cell lipoma in the oral cavity is a benign entity. Analysis of the reported cases does not suggest any strong sex or race predilection. Age at presentation varies widely, and can be seen mostly in adults of any age. The presence of a painless, slow growing, rubbery, submucosal mass with intact overlying mucosa should alert the clinician to consider this entity in the differential diagnosis. The diagnosis of spindle cell lipoma can often be made with observation of key histologic features after routine hematoxylin-eosin staining. Special effort must be made to differentiate spindle cell lipoma from more aggressive entities requiring more radical treatment. Treatment for spindle cell lipoma involves simple excision, and has not been shown to lead to recurrence. References 1. Enzinger FM, Weiss SW: Soft Tissue Tumors (ed 3). St Louis, MO, Mosby Year Book, 1995 2. Roux M: On exostoses: Their character. Am J Dent Sci 1848;9:133-134 3. Bouquot J, Nikai H: Lesions of the oral cavity, in Gnepp DR: Diagnostic Surgical Pathology of the Head and Neck. Philadelphia, PA, Saunders, 2000, pp 141–238 4. Barnes L: Tumors and tumor like lesions of the soft tissues, in Barnes L (ed): Surgical Pathology of the Head and Neck. New York, NY, Marcel Dekker, 1985, pp 749-755 5. McDaniel RK, Newland JR, Chiles DG: Intraoral spindle cell lipoma: Case report with correlated light and electron microscopy. Oral Surg Oral Med Oral Pathol 1984;57:52-57 6. Khoo SP, Lian CB: Intraoral spindle-cell lipoma: Report of a case and literature review. Ann Dent 1995;54:53-55 7. Lombardi T, Odell EW: Spindle cell lipoma of the oral cavity: Report of a case. J Oral Pathol Med 1984;23:237-239 8. Levy FE: Goding spindle cell lipoma: An unusual oral presentation. Otolaryngol Head Neck Surg 1989;101:601-603 9. Christopoulos P, Nicolatou O, Patrikiou A: Oral spindle cell lipoma. Report of a case. Int J Oral Maxillofac Surg 1989; 8:208-209
10. Tosios K, Papanicolaou SI, Kapranos N, et al: Spindle cell lipoma of the oral cavity. Int J Oral Maxillofac Surg 1995;24:363364 11. Dutt SN, East DM, Saleem Y, et al: Spindle cell variant of intralingual lipoma. Report of a case with literature review. J Laryngol Otol 1999;113:587-589 12. Piattelli A, Fioroni M, Rubini C: Spindle cell lipoma of the oral cavity: Report of a case. J Oral Maxillofac Surg 1999;57:624625 13. Gorelking L, Conrad-England R: Spindle cell lipoma: A benign lipoma variant with potential hazards of diagnostic misinterpretation. South Med J 1978;71:1163-1164 14. Baker SE, Jensen JL, Correll RW: Lipomas of the parotid gland. Oral Surg Oral Med Oral Pathol 1981;52:167-170 15. Cowdin JT, Dew JH: Fatty infiltration of parotid glands: Report of a case. Arch Surg 1958;76:525-526 16. Janecka IP, Conley J, Perzin KH, et al: Lipomas presenting as parotid tumors. Laryngoscope 1977;87:1007-1010 17. Walts AE, Perzik SL: Lipomatous lesions of the parotid area. Arch Otolaryngol 1976;102:230-232 18. Greer RO, Richardson JF: The nature of lipomas and their significance in the oral cavity: Review and report of cases. Oral Surg 1973;36:551-557 19. Hatziotis JC: Lipoma of the oral cavity. Oral Surg 1971; 31:511-524 20. Seldin HM, Seldin SD, Rakower W, et al: Lipomas of the oral cavity: Report of 26 cases. J Oral Surg 1967;25:270-274 21. Lekkas C, Van Hoof R: Lipoma of the tongue. Oral Surg 1979;48:214-215 22. Pisanty S: Bilateral lipomas of the tongue. Oral Surg 1976;42:451-453 23. Putney FJ, Fry KE: Retropharyngeal lipoma. J Otol Rhinol Laryngol 1965;74:967-972 24. Yonus M: Retropharyngeal lipoma. J Laryngol Otol 1980; 94:321-325 25. Mannson I, Wilske J, Kindblom LG: Lipoma of the hypopharynx: A case report and review of literature. J Laryngol Otol 1978;92:1037-1043 26. Enzinger FM, Harvey DA: Spindle cell lipoma. Cancer 1975;36:1852-1859 27. Fletcher CD, Martin-Bates E: Spindle cell lipoma: A clinicopathological study with some original observations. Histopathology 1987;11:803-817 28. Angervall L, Dahl I, Kindblom LG, et al: Spindle cell lipoma. Acta Pathol Microbiol Scand [A] 1976;84:477-487 29. Clawson JR, Kline KK, Armbrecht EC: Trauma induced avulsion of the buccal fat pad into the mouth. Report of a case. J Oral Surg 1968;26:546-547 30. Brooke RI: Traumatic herniation of buccal pad of fat (traumatic pseudolipoma). A review. Oral Surg Oral Med Oral Pathol 1978;45:689-691 31. Berk CW, Gibson WS Jr: Pathologic quiz case 1. Traumatic herniated gangrenous buccal fat pad (traumatic pseudolipoma). Arch Otolaryngol Head Neck Surg 1994;120:340-342 32. Brooke RI, MacGregor AJ: Traumatic pseudolipoma of the buccal mucosa. Oral Surg Oral Med Oral Pathol 1969;28: 223-225 33. Neville B, Damm D, Allen C, et al: Soft tissue tumors, in: Textbook of Oral and Maxillofacial Pathology. Philadelphia, PA, Saunders, 1995, pp 362-415 34. Beham A, Schmid C, Hodl S, et al: Spindle cell and
Oral Spindle Cell Lipoma pleomorphic lipoma: An immunohistochemical study and histogenetic analysis. J Pathol 1989;158:219-222 35. Laskin WB, Fetsch JF, Mostofi FK: Angiomyofibroblastoma like tumor of the male genital tract: Analysis of 11 cases with comparison to female angiomyofibroblastoma and spindle cell lipoma. Am J Surg Path 1998;22:6-16
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36. Mulvany NJ, Silvester AC, Collins JP: Spindle cell lipoma of the breast. Pathology 1999;31:288-291 37. Suster S, Fisher C, Moran CA: Dendritic fibromyxolipoma: Clinicopathologic study of a distinctive benign soft tissue lesion that may be mistaken for a sarcoma. Ann Diagn Pathol 1998;2:111-120