- Email: [email protected]
Ulcerated mass of the retromolar area
oo o
Vol. 93 No. 6 June 2002
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY CLINICOPATHOLOGIC CONFERENCE
Editor: John R. Kalmar
Ulcerated mass of the retromolar area Bruno Courrier, DDS,a Franc¸oise Plantier, MD,b and Roger Ku¨ffer, MD,c Paris, France UNIVERSITY OF PARIS, COCHIN HOSPITAL, AND GENEVE HOSPITAL
(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:635-9)
CASE REPORT
Differential diagnosis
A 37-year-old man appeared for examination in our office in 1997 with a complaint of a congenitally missing right maxillary canine, which was confirmed by routine radiography. His medical history was unremarkable, and no other abnormalities were detected on oral examination. An implant procedure was performed in the area without complication. One year after his dental implant surgery, the patient appeared again for evaluation and treatment of symptomatic wisdom teeth on the left side. In addition to evidence of pericoronitis affecting both the maxillary and mandibular left third molars, an asymptomatic, white-gray to pink, sessile nodule, measuring 1.5 cm in diameter, was noted on the posterior aspect of the left cheek, just lateral to the retromolar pad. A small, central ulceration, thought to be trauma-related, was observed, but the patient denied trauma to the area or any associated symptoms (Fig 1). The nodule was rubbery-firm and mobile to palpation. Despite medical advice, the patient refused to have the lesion biopsied but elected to have his upper and lower left third molars extracted. A year later, the patient returned for extraction of the wisdom teeth on the right side. Intraorally, the previous extraction sites appeared well-healed. The soft tissue mass, by contrast, had become more exophytic and erythematous with a greater degree of ulceration (Fig 2). The patient claimed that the mass had remained totally asymptomatic since his previous extractions. During anamnesis, however, the patient confessed to a habit of chronically sucking in the cheeks and chewing the mucosa on this side. No other clinical abnormalities were noted intraorally.
With the patient’s admission of a parafunctional habit, the clinical features and behavior of this lesion were thought to be most consistent with a traumatically induced, reactive process such as pyogenic granuloma or inflammatory fibrous hyperplasia. Although the area was in close proximity to the posterior mandibular alveolar tissue, reactive gingival or alveolar proliferations such as peripheral giant cell granuloma or peripheral ossifying fibroma were not considered likely because of clinical evidence of mobility. Other considerations in the differential included a variety of benign connective tissue neoplasms, salivary gland neoplasia such as pleomorphic adenoma or mucoepidermoid carcinoma, and a peripheral odontogenic tumor such as ameloblastoma or calcifying epithelial odontogenic tumor.
a
School of Dentistry Garancie`re, Hoˆtel Dieu Hospital, University of Paris. b Division of Anatomic Pathology, Department of Laboratory Medicine, Tarnier’s Center, Cochin Hospital, Paris. c Division of Anatomic Pathology, Department of Laboratory Medicine, Geneve Hospital, Geneva, Switzerland. Copyright © 2002 by Mosby, Inc. 1079-2104/2002/$35.00 ⫹ 0 7/14/124765 doi:10.1067/moe.2002.124765
Diagnosis Because of its size and localized, indolent behavior, the tumor was excised with the patient under local anesthesia, together with a small margin of adjacent muscle. At the time of surgery, the mass was found to separate easily from the buccal fat pad at the deep and lateral margins. Histopathologic evaluation of hematoxylin-eosin-stained sections showed an ulcerated, cellular tumor arranged in well-defined lobules. A circumscribed but unencapsulated margin was observed with focal, limited infiltration of surrounding skeletal muscle. The tumor was composed of spindle-shaped cells with indistinct cytoplasm and vesicular nuclei exhibiting vague storiform arrangements (Fig 3). Rare, coarse collagen bundles were seen within the lesion, and a prominent microvasculature was noted. Normal mitoses were observed, with an average of roughly 2 per 10 high-power fields (hpf). No nuclear or cellular pleomorphism was seen, and no evidence of calcification or necrosis was identified. A preliminary histopathologic interpretation was made of “benign spindle-cell proliferation.” The reviewing pathologists indicated that although a diagnosis of solitary fibrous tumor (SFT) was favored, immunohistochemical (IHC) probes would be necessary to provide a definitive diagnosis.
635
636 Courrier, Plantier, and Ku¨ffer
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 2002
Fig 1. Slightly exophytic, white-gray to pink, submucosal nodule of the left retromolar area.
Fig 2. Left retromolar area 1 year later after removal of lower left third molar. Note enlargement and more extensive surface ulceration of the asymptomatic soft tissue mass.
For such cases, a new differential diagnosis can be constructed on the basis of the microscopic features, and a final diagnosis is often made through analysis of the antigenic markers expressed by lesional tissue.
whorls or fascicles of bland oval to spindle cells with eosinophilic, slightly fibrillar cytoplasm. A multinodular appearance is commonly observed as a result of a characteristic zonation of light- and dark-staining areas that corresponds to relative hypocellularity and hypercellularity within the tumor. A prominent microvasculature is typical, and mitoses are usually inconspicuous. Lesional cells commonly express vimentin, smooth muscle actin, and muscle-specific actin. Nodular fasciitis is a reactive, pseudosarcomatous process composed of fibroblasts and myofibroblasts that usually occurs between the ages of 20 and 40 years and may present in the head and neck.6 Most cases are characterized by a micronodular proliferation of spindle cells admixed with delicate fascicles of collagen fibers and foci of mucinous ground substance that produce a “feathery” appearance. Although somewhat circumscribed at low magnification, closer inspection often shows an infiltrative margin. Scattered lymphoid cells and erythrocytes are typically seen among the lesional tissue. Consistent with a myofibroblastic origin, lesions of nodular fasciitis are usually positive for vimentin, smooth muscle actin, and muscle-specific actin.
Microscopic differential diagnosis SFT is a relatively uncommon neoplasm that preferentially occurs within the thoracic cavity but has been reported in numerous extrapleural sites, including the oral cavity.1,2 It is described as densely cellular proliferation of spindle-shaped cells with a prominent, hemangiopericytoma-like vasculature admixed with areas of dense hyalinization. Vague storiform or fascicular arrangements may be seen, but lesions often exhibit a widely variable or “patternless” architecture. By IHC analysis, the tumor cells are consistently positive for vimentin, CD34, and bcl-2.2-4 Malignant variants have been reported; however, these lesions have exhibited destructive margins, cellular pleomorphism, and increased mitotic figures as well as occasional areas of necrosis or calcification. Solitary myofibroma is a soft tissue lesion with a predilection for the head and neck region.5 It is composed of vague
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
Courrier, Plantier, and Ku¨ ffer 637
Fig 3. Medium-power photomicrograph depicting cellular proliferation of spindle-shaped cells exhibiting a vague storiform architecture (hematoxylin-eosin stain, original magnification ⫻25).
Fig 4. Lesional cells with strong, uniform expression of CD34 (original magnification ⫻25).
Desmoid tumor (extra-abdominal fibromatosis) is a characteristically infiltrative lesion that may occur in the head and neck, especially in children or young adults.7 Oral presentations, however, are uncommon. These tumors feature a monotonous proliferation of spindle-shaped cells, often arranged in fascicles, that are separated by abundant, dense collagen. The associated vasculature is usually inconspicuous. Tumor cells are uniformly positive for vimentin, variably express smooth muscle actin and muscle-specific actin, and are negative for CD34.4,7 Spindle cell lipoma primarily occurs in the neck and shoulder area, although oral examples have been reported.1 This tumor usually has a prominent vascular pattern, and the spindle-shaped cells may be associated with focally abundant collagen as well as frequent mast cells. The diagnosis is aided by the finding of variable numbers of mature adipocytes
enclosed by the spindle cell component. By IHC analysis, these proliferations are positive for vimentin, CD34, and bcl-2.3,4,8 The spindle cell population is usually negative for S100; however, this marker is strongly expressed by the associated mature fat cells. Benign fibrous histiocytoma is a vaguely circumscribed proliferation of spindle-shaped cells that usually exhibits vague storiform arrangements in association with delicate collagen fibers, although occasional areas of hyalinization may be seen. Variably numerous multinucleated giant cells and aggregates of foamy histiocytes are often identified. Lesions are usually positive for vimentin and factor XIIIa, with focal positivity for CD68 (histiocytes and giant cells) as well as rare CD34 expression.1,5,8 Malignant spindle cell proliferations such as leiomyosarcoma, malignant fibrous histiocytoma, fibrosarcoma, and der-
638 Courrier, Plantier, and Ku¨ ffer
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 2002
Table I. Solitary fibrous tumor of the oral cavity Patient age(y)/gender
Location
50/M 50/F 55/M 66/M 34/F 53/M
Size (cm)
Duration
Reference, case no.
Right sublingual gland area Soft palate Left internal cheek Tongue Left buccal mucosa Oral cavity
3 4 2 1 1.5 2.2
11 9, case 7 12 13 14 15, case 14
46/F
Right buccal mucosa
2.9
27/M 39/F 70/M 56/M 45/F 70/M 38/M
Anterior buccal mucosa of the lip Lingual aspect, left retromolar triangle Left buccal mucosa Right cheek Left cheek Left cheek Left posterior cheek
2 1 4 2 1.5 1 2.5
12 y ⬍1 y NA 1y 3y 2 mo-4 y 2 mo-4 y 5y 4 wk NA ⬍10 y 6 mo 5 mo ⬍3 y
15, case 15 16 4, case 1 4, case 2 17, case 1 17, case 2 17, case 3 Current case
NA, Not available.
matofibrosarcoma protuberans (DFSP) should be distinguishable from benign or reactive proliferations by features such as extensive marginal infiltration, cellular or nuclear atypia, numerous or abnormal mitotic figures, and tumor necrosis. In addition, these sarcomatous neoplasms usually exhibit distinct IHC profiles that aid in their categorization. CD34 expression, however, can be seen in fibrosarcoma and is strongly expressed in most cases of DFSP as well as malignant variants of SFT.3,4,9 By IHC analysis of the current case, lesional cells proved to be strongly positive for vimentin, CD34 (Fig 4), bcl-2, and CD99. Weaker expression of Ki-67 (MIB 1) was noted. Probes for smooth muscle actin, pancytokeratins, desmin, epithelial membrane antigen (EMA), and S-100 were negative. Despite the presence of an average of 2 mitoses per 10 hpf, the relatively well-circumscribed tumor margin and lack of cellular pleomorphism were thought to be most consistent with a benign neoplasm. The final diagnosis was benign SFT.
Management Because the tumor margin was free of involvement, no additional treatment was deemed necessary. Two years after resection, no evidence of recurrence could be identified during routine follow-up examination.
DISCUSSION SFT is a relatively uncommon lesion typically seen in adults between the fourth and seventh decades of life.1,2 It was first described in 193110 as a primary pleural neoplasm that often presented as circumscribed, rounded masses attached to either the parietal or visceral pleura. More recently, it has been recognized that this tumor may occur over a wide range of anatomic sites, with a total of 13 previously reported cases involving the oral cavity (Table).4,9,11-17 The oral lesions
have presented as well-circumscribed, soft to rubbery, gray to tan-pink, submucosal masses ranging in size from 1 to 4 cm in diameter. Reported duration has varied from a few weeks to several years. Most cases have been asymptomatic with a normal-appearing overlying mucosa, and an association with trauma has been noted in only 2 of the previously reported lesions.17 On histopathologic examination, the SFT is an unencapsulated proliferation of spindle-shaped cells that often exhibit a patternless pattern (any combination of short storiform, fascicular, herringbone, and/or hemangiopericytomatous arrangements).8 This polymorphous, patternless quality is, paradoxically, considered characteristic for these neoplasms.18 Because of cellular, architectural, and IHC profile similarities, some authorities believe that cases previously diagnosed as hemangiopericytoma may actually represent monophasic variants of SFT.3,8,9 As in this case, the diagnosis of SFT is often supported by IHC analysis. Others have suggested a role for comparative genomic hybridization.19 SFT typically exhibits a strongly positive reaction for vimentin, CD34, and bcl-2 with variable expression of CD99, factor XIIIa, and Ki 67 (MIB 1).2-4,8,18,20 Most cases are uniformly negative for S-100, cytokeratins, smooth muscle and muscle-specific actins, desmin, and EMA. Nielsen et al2 reported that their cases of malignant SFT exhibited 2 or more mitoses per 10 hpf, together with cytologic atypia. Others suggest that, in the absence of other architectural or cytologic features of malignancy, up to 4 or 5 normal mitoses per 10 hpf can be consistent with the diagnosis of benign SFT.8,18 In summary, we report an unusual intraoral presen-
Courrier, Plantier, and Ku¨ ffer 639
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
tation of benign SFT that closely mimicked more common reactive proliferations such as inflammatory fibrous hyperplasia or pyogenic granuloma. This case illustrates the histopathologic and IHC features that are used to help distinguish various spindle cell proliferations that may occur in the oral cavity. To date, all oral cases of SFT have exhibited a benign clinical course with no evidence of recurrence or metastasis. Despite this indolent behavior, the limited number of cases warrants careful, long-term follow-up for these unusual spindle cell neoplasms. REFERENCES 1. Enzinger FM, Weis SW. Soft tissue tumors. 3rd ed. St Louis: Mosby; 1995. 2. Nielsen GP, O’Connell JX, Dickersin GR, Rosenberg AE. Solitary fibrous tumor of soft tissue: a report of 15 cases, including 5 malignant examples with light microscopic, immunohistochemical, and ultrastructural data. Mod Pathol 1997;10:1028-37. 3. Suster S, Fisher C, Moran CA. Expression of bcl-2 oncoprotein in benign and malignant spindle cell tumors of soft tissue, skin, serosal surfaces, and gastrointestinal tract. Am J Surg Pathol 1998;22:863-72. 4. Perez-Ordonez B, Koutlas IG, Strich E, Gilbert RW, Jordan RCK. Solitary fibrous tumor of the oral cavity: an uncommon location for a ubiquitous neoplasm. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:589-93. 5. Beham A, Badve S, Suster S, Fletcher CDM. Solitary myofibroma in adults: clinicopathologic analysis of a series. Histopathology 1993;22:335-41. 6. Eversole LR, Christensen R, Ficarra G, Pierleoni L, Sapp JP. Nodular fasciitis and solitary fibrous tumor of the oral region: tumors of fibroblast heterogeneity. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:471-6. 7. Fowler CB, Hartman KS, Brannon RB. Fibromatosis of the oral and paraoral region. Oral Surg Oral Med Oral Pathol 1994;77: 373-86. 8. Cowper SE. Solitary fibrous tumor of the skin. Am J Dermatopathol 1999;21:213-9. 9. Suster S, Nascimento AG, Miettinen M, Sickel JZ, Moran CA.
10. 11. 12. 13. 14. 15. 16.
17.
18. 19.
20.
Solitary fibrous tumors of soft tissue: a clinicopathologic and immunohistochemical study of 12 cases. Am J Surg Pathol 1995;19:1257-66. Klemperer P, Rabin CB. Primary neoplasms of the pleura: a report of five cases. Arch Pathol 1931;11:385-412. ¨ , Yildiz FR, Celasun B, O ¨ nder T, Finci R. Solitary Gu¨ nhan O fibrous tumour arising from sublingual gland: report of a case. J Laryngol Otol 1994;108:998-1000. Fornelli A, Cocchi R, Eusebi V. Solitary fibrous tumor of the cheek. Pathologica 1996;88:36-9. Piattelli A, Fioroni M, Rubini C. Solitary fibrous tumour of the tongue. Oral Oncol 1998;34:431-4. Kurihara K, Mizuseki K, Sonobe J, Yanagihara J. Solitary fibrous tumor of the oral cavity: report of a case. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:223-6. Brunnemann RB, Ro JY, Ordonez NG, Mooney J, El-Naggar AK, Ayala AG. Extrapleural solitary fibrous tumor: a clinicopathologic study of 24 cases. Mod Pathol 1999;12:1034-42. Iwai S, Nakazawa M, Yoshikawa F, Amekawa S, Sakuda M. Solitary fibrous tumor of the buccal mucosa: report of a case with immunohistochemical studies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:461-5. Lukinmaa P-L, Hietanen J, Warfvinge G, Sane J, Tuominen S, Henriksson V, et al. Solitary fibrous tumour of the oral cavity: clinicopathological and immunohistochemical characterization of three cases. J Oral Pathol Med 2000;29:186-92. Chan JKC. Solitary fibrous tumour: everywhere, and a diagnosis in vogue. Histopathology 1997;31:568-76. Miettinen MM, El-Rifai W, Sarlomo-Rikala M, Andersson LC, Knuutila S. Tumor size-related DNA copy number changes occur in solitary fibrous tumors but not in hemangiopericytomas. Mod Pathol 1997;10:1194-200. Hasegawa T, Matsuno Y, Shimoda T, Hirohashi S, Hirose T, Sano T. Frequent expression of bcl-2 protein in solitary fibrous tumors. Jpn J Clin Oncol 1998;28:86-91.
Reprint requests: Bruno Courrier, DDS 3, Rue Anatole de la Forge 75017 Paris France [email protected]
Vol. 93 No. 6 June 2002
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY CLINICOPATHOLOGIC CONFERENCE
Editor: John R. Kalmar
Ulcerated mass of the retromolar area Bruno Courrier, DDS,a Franc¸oise Plantier, MD,b and Roger Ku¨ffer, MD,c Paris, France UNIVERSITY OF PARIS, COCHIN HOSPITAL, AND GENEVE HOSPITAL
(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:635-9)
CASE REPORT
Differential diagnosis
A 37-year-old man appeared for examination in our office in 1997 with a complaint of a congenitally missing right maxillary canine, which was confirmed by routine radiography. His medical history was unremarkable, and no other abnormalities were detected on oral examination. An implant procedure was performed in the area without complication. One year after his dental implant surgery, the patient appeared again for evaluation and treatment of symptomatic wisdom teeth on the left side. In addition to evidence of pericoronitis affecting both the maxillary and mandibular left third molars, an asymptomatic, white-gray to pink, sessile nodule, measuring 1.5 cm in diameter, was noted on the posterior aspect of the left cheek, just lateral to the retromolar pad. A small, central ulceration, thought to be trauma-related, was observed, but the patient denied trauma to the area or any associated symptoms (Fig 1). The nodule was rubbery-firm and mobile to palpation. Despite medical advice, the patient refused to have the lesion biopsied but elected to have his upper and lower left third molars extracted. A year later, the patient returned for extraction of the wisdom teeth on the right side. Intraorally, the previous extraction sites appeared well-healed. The soft tissue mass, by contrast, had become more exophytic and erythematous with a greater degree of ulceration (Fig 2). The patient claimed that the mass had remained totally asymptomatic since his previous extractions. During anamnesis, however, the patient confessed to a habit of chronically sucking in the cheeks and chewing the mucosa on this side. No other clinical abnormalities were noted intraorally.
With the patient’s admission of a parafunctional habit, the clinical features and behavior of this lesion were thought to be most consistent with a traumatically induced, reactive process such as pyogenic granuloma or inflammatory fibrous hyperplasia. Although the area was in close proximity to the posterior mandibular alveolar tissue, reactive gingival or alveolar proliferations such as peripheral giant cell granuloma or peripheral ossifying fibroma were not considered likely because of clinical evidence of mobility. Other considerations in the differential included a variety of benign connective tissue neoplasms, salivary gland neoplasia such as pleomorphic adenoma or mucoepidermoid carcinoma, and a peripheral odontogenic tumor such as ameloblastoma or calcifying epithelial odontogenic tumor.
a
School of Dentistry Garancie`re, Hoˆtel Dieu Hospital, University of Paris. b Division of Anatomic Pathology, Department of Laboratory Medicine, Tarnier’s Center, Cochin Hospital, Paris. c Division of Anatomic Pathology, Department of Laboratory Medicine, Geneve Hospital, Geneva, Switzerland. Copyright © 2002 by Mosby, Inc. 1079-2104/2002/$35.00 ⫹ 0 7/14/124765 doi:10.1067/moe.2002.124765
Diagnosis Because of its size and localized, indolent behavior, the tumor was excised with the patient under local anesthesia, together with a small margin of adjacent muscle. At the time of surgery, the mass was found to separate easily from the buccal fat pad at the deep and lateral margins. Histopathologic evaluation of hematoxylin-eosin-stained sections showed an ulcerated, cellular tumor arranged in well-defined lobules. A circumscribed but unencapsulated margin was observed with focal, limited infiltration of surrounding skeletal muscle. The tumor was composed of spindle-shaped cells with indistinct cytoplasm and vesicular nuclei exhibiting vague storiform arrangements (Fig 3). Rare, coarse collagen bundles were seen within the lesion, and a prominent microvasculature was noted. Normal mitoses were observed, with an average of roughly 2 per 10 high-power fields (hpf). No nuclear or cellular pleomorphism was seen, and no evidence of calcification or necrosis was identified. A preliminary histopathologic interpretation was made of “benign spindle-cell proliferation.” The reviewing pathologists indicated that although a diagnosis of solitary fibrous tumor (SFT) was favored, immunohistochemical (IHC) probes would be necessary to provide a definitive diagnosis.
635
636 Courrier, Plantier, and Ku¨ffer
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 2002
Fig 1. Slightly exophytic, white-gray to pink, submucosal nodule of the left retromolar area.
Fig 2. Left retromolar area 1 year later after removal of lower left third molar. Note enlargement and more extensive surface ulceration of the asymptomatic soft tissue mass.
For such cases, a new differential diagnosis can be constructed on the basis of the microscopic features, and a final diagnosis is often made through analysis of the antigenic markers expressed by lesional tissue.
whorls or fascicles of bland oval to spindle cells with eosinophilic, slightly fibrillar cytoplasm. A multinodular appearance is commonly observed as a result of a characteristic zonation of light- and dark-staining areas that corresponds to relative hypocellularity and hypercellularity within the tumor. A prominent microvasculature is typical, and mitoses are usually inconspicuous. Lesional cells commonly express vimentin, smooth muscle actin, and muscle-specific actin. Nodular fasciitis is a reactive, pseudosarcomatous process composed of fibroblasts and myofibroblasts that usually occurs between the ages of 20 and 40 years and may present in the head and neck.6 Most cases are characterized by a micronodular proliferation of spindle cells admixed with delicate fascicles of collagen fibers and foci of mucinous ground substance that produce a “feathery” appearance. Although somewhat circumscribed at low magnification, closer inspection often shows an infiltrative margin. Scattered lymphoid cells and erythrocytes are typically seen among the lesional tissue. Consistent with a myofibroblastic origin, lesions of nodular fasciitis are usually positive for vimentin, smooth muscle actin, and muscle-specific actin.
Microscopic differential diagnosis SFT is a relatively uncommon neoplasm that preferentially occurs within the thoracic cavity but has been reported in numerous extrapleural sites, including the oral cavity.1,2 It is described as densely cellular proliferation of spindle-shaped cells with a prominent, hemangiopericytoma-like vasculature admixed with areas of dense hyalinization. Vague storiform or fascicular arrangements may be seen, but lesions often exhibit a widely variable or “patternless” architecture. By IHC analysis, the tumor cells are consistently positive for vimentin, CD34, and bcl-2.2-4 Malignant variants have been reported; however, these lesions have exhibited destructive margins, cellular pleomorphism, and increased mitotic figures as well as occasional areas of necrosis or calcification. Solitary myofibroma is a soft tissue lesion with a predilection for the head and neck region.5 It is composed of vague
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
Courrier, Plantier, and Ku¨ ffer 637
Fig 3. Medium-power photomicrograph depicting cellular proliferation of spindle-shaped cells exhibiting a vague storiform architecture (hematoxylin-eosin stain, original magnification ⫻25).
Fig 4. Lesional cells with strong, uniform expression of CD34 (original magnification ⫻25).
Desmoid tumor (extra-abdominal fibromatosis) is a characteristically infiltrative lesion that may occur in the head and neck, especially in children or young adults.7 Oral presentations, however, are uncommon. These tumors feature a monotonous proliferation of spindle-shaped cells, often arranged in fascicles, that are separated by abundant, dense collagen. The associated vasculature is usually inconspicuous. Tumor cells are uniformly positive for vimentin, variably express smooth muscle actin and muscle-specific actin, and are negative for CD34.4,7 Spindle cell lipoma primarily occurs in the neck and shoulder area, although oral examples have been reported.1 This tumor usually has a prominent vascular pattern, and the spindle-shaped cells may be associated with focally abundant collagen as well as frequent mast cells. The diagnosis is aided by the finding of variable numbers of mature adipocytes
enclosed by the spindle cell component. By IHC analysis, these proliferations are positive for vimentin, CD34, and bcl-2.3,4,8 The spindle cell population is usually negative for S100; however, this marker is strongly expressed by the associated mature fat cells. Benign fibrous histiocytoma is a vaguely circumscribed proliferation of spindle-shaped cells that usually exhibits vague storiform arrangements in association with delicate collagen fibers, although occasional areas of hyalinization may be seen. Variably numerous multinucleated giant cells and aggregates of foamy histiocytes are often identified. Lesions are usually positive for vimentin and factor XIIIa, with focal positivity for CD68 (histiocytes and giant cells) as well as rare CD34 expression.1,5,8 Malignant spindle cell proliferations such as leiomyosarcoma, malignant fibrous histiocytoma, fibrosarcoma, and der-
638 Courrier, Plantier, and Ku¨ ffer
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY June 2002
Table I. Solitary fibrous tumor of the oral cavity Patient age(y)/gender
Location
50/M 50/F 55/M 66/M 34/F 53/M
Size (cm)
Duration
Reference, case no.
Right sublingual gland area Soft palate Left internal cheek Tongue Left buccal mucosa Oral cavity
3 4 2 1 1.5 2.2
11 9, case 7 12 13 14 15, case 14
46/F
Right buccal mucosa
2.9
27/M 39/F 70/M 56/M 45/F 70/M 38/M
Anterior buccal mucosa of the lip Lingual aspect, left retromolar triangle Left buccal mucosa Right cheek Left cheek Left cheek Left posterior cheek
2 1 4 2 1.5 1 2.5
12 y ⬍1 y NA 1y 3y 2 mo-4 y 2 mo-4 y 5y 4 wk NA ⬍10 y 6 mo 5 mo ⬍3 y
15, case 15 16 4, case 1 4, case 2 17, case 1 17, case 2 17, case 3 Current case
NA, Not available.
matofibrosarcoma protuberans (DFSP) should be distinguishable from benign or reactive proliferations by features such as extensive marginal infiltration, cellular or nuclear atypia, numerous or abnormal mitotic figures, and tumor necrosis. In addition, these sarcomatous neoplasms usually exhibit distinct IHC profiles that aid in their categorization. CD34 expression, however, can be seen in fibrosarcoma and is strongly expressed in most cases of DFSP as well as malignant variants of SFT.3,4,9 By IHC analysis of the current case, lesional cells proved to be strongly positive for vimentin, CD34 (Fig 4), bcl-2, and CD99. Weaker expression of Ki-67 (MIB 1) was noted. Probes for smooth muscle actin, pancytokeratins, desmin, epithelial membrane antigen (EMA), and S-100 were negative. Despite the presence of an average of 2 mitoses per 10 hpf, the relatively well-circumscribed tumor margin and lack of cellular pleomorphism were thought to be most consistent with a benign neoplasm. The final diagnosis was benign SFT.
Management Because the tumor margin was free of involvement, no additional treatment was deemed necessary. Two years after resection, no evidence of recurrence could be identified during routine follow-up examination.
DISCUSSION SFT is a relatively uncommon lesion typically seen in adults between the fourth and seventh decades of life.1,2 It was first described in 193110 as a primary pleural neoplasm that often presented as circumscribed, rounded masses attached to either the parietal or visceral pleura. More recently, it has been recognized that this tumor may occur over a wide range of anatomic sites, with a total of 13 previously reported cases involving the oral cavity (Table).4,9,11-17 The oral lesions
have presented as well-circumscribed, soft to rubbery, gray to tan-pink, submucosal masses ranging in size from 1 to 4 cm in diameter. Reported duration has varied from a few weeks to several years. Most cases have been asymptomatic with a normal-appearing overlying mucosa, and an association with trauma has been noted in only 2 of the previously reported lesions.17 On histopathologic examination, the SFT is an unencapsulated proliferation of spindle-shaped cells that often exhibit a patternless pattern (any combination of short storiform, fascicular, herringbone, and/or hemangiopericytomatous arrangements).8 This polymorphous, patternless quality is, paradoxically, considered characteristic for these neoplasms.18 Because of cellular, architectural, and IHC profile similarities, some authorities believe that cases previously diagnosed as hemangiopericytoma may actually represent monophasic variants of SFT.3,8,9 As in this case, the diagnosis of SFT is often supported by IHC analysis. Others have suggested a role for comparative genomic hybridization.19 SFT typically exhibits a strongly positive reaction for vimentin, CD34, and bcl-2 with variable expression of CD99, factor XIIIa, and Ki 67 (MIB 1).2-4,8,18,20 Most cases are uniformly negative for S-100, cytokeratins, smooth muscle and muscle-specific actins, desmin, and EMA. Nielsen et al2 reported that their cases of malignant SFT exhibited 2 or more mitoses per 10 hpf, together with cytologic atypia. Others suggest that, in the absence of other architectural or cytologic features of malignancy, up to 4 or 5 normal mitoses per 10 hpf can be consistent with the diagnosis of benign SFT.8,18 In summary, we report an unusual intraoral presen-
Courrier, Plantier, and Ku¨ ffer 639
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 93, Number 6
tation of benign SFT that closely mimicked more common reactive proliferations such as inflammatory fibrous hyperplasia or pyogenic granuloma. This case illustrates the histopathologic and IHC features that are used to help distinguish various spindle cell proliferations that may occur in the oral cavity. To date, all oral cases of SFT have exhibited a benign clinical course with no evidence of recurrence or metastasis. Despite this indolent behavior, the limited number of cases warrants careful, long-term follow-up for these unusual spindle cell neoplasms. REFERENCES 1. Enzinger FM, Weis SW. Soft tissue tumors. 3rd ed. St Louis: Mosby; 1995. 2. Nielsen GP, O’Connell JX, Dickersin GR, Rosenberg AE. Solitary fibrous tumor of soft tissue: a report of 15 cases, including 5 malignant examples with light microscopic, immunohistochemical, and ultrastructural data. Mod Pathol 1997;10:1028-37. 3. Suster S, Fisher C, Moran CA. Expression of bcl-2 oncoprotein in benign and malignant spindle cell tumors of soft tissue, skin, serosal surfaces, and gastrointestinal tract. Am J Surg Pathol 1998;22:863-72. 4. Perez-Ordonez B, Koutlas IG, Strich E, Gilbert RW, Jordan RCK. Solitary fibrous tumor of the oral cavity: an uncommon location for a ubiquitous neoplasm. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:589-93. 5. Beham A, Badve S, Suster S, Fletcher CDM. Solitary myofibroma in adults: clinicopathologic analysis of a series. Histopathology 1993;22:335-41. 6. Eversole LR, Christensen R, Ficarra G, Pierleoni L, Sapp JP. Nodular fasciitis and solitary fibrous tumor of the oral region: tumors of fibroblast heterogeneity. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:471-6. 7. Fowler CB, Hartman KS, Brannon RB. Fibromatosis of the oral and paraoral region. Oral Surg Oral Med Oral Pathol 1994;77: 373-86. 8. Cowper SE. Solitary fibrous tumor of the skin. Am J Dermatopathol 1999;21:213-9. 9. Suster S, Nascimento AG, Miettinen M, Sickel JZ, Moran CA.
10. 11. 12. 13. 14. 15. 16.
17.
18. 19.
20.
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