Posttraumatic spindle cell nodule of the buccal mucosa Report of a case Robin A. Zellers, MD, William J. Bicket, MD, and Michael
G. Parker, MD, Akron, Ohio
DEPARTMENTS
GENERAL
OF PATHOLOGY
AND
PLASTIC
SURGERY,
AKRON
MEDICAL
CENTER
A benign posttraumatic spindle cell proliferation arising at a site of laceration in the buccal mucosa of a 19-year old man is described. This lesion, which histologically mimicked a leiomyosarcoma, appears to represent a reactive process similar to that described as postoperative spindle cell nodules of the genitourinary tract. Reexcision of the area 1 month after biopsy revealed only scar formation and mild chronic inflammation. Recognition of this type of benign spindle cell proliferation at traumatized sites in the oral cavity is important if misdiagnosis and subsequent aggressive therapy is to be avoided. (ORAL SURC ORAL MED ORAL PATHOL 1992;74:212-5)
D
iagnostic difficulties may be encountered in the histologic interpretation of proliferative spindle cell lesions in any body site. Pseudoneoplastic proliferations may especially represent diagnostic pitfalls in that they clinically and histologically may be mistaken for malignant tumors. Benign postoperative spindle cell nodules resembling sarcomas of the genitourinary tract have recently been described as a distinct clinicopathologic entity. These nodules represent benign reactive spindle cell lesions that are distinct histologically from other types of benign proliferative lesions of soft tissues such as nodular fasciitis. They may be mistaken histologically for leiomyosarcoma or Kaposi’s sarcoma.’ We describe a similar benign spindle cell lesion that developed in the oral cavity after trauma to the buccal mucosa. Recognition of posttraumatic spindle cell nodules is important if the potentially serious consequences of misdiagnosis of malignancy are to be avoided. CASE REPORT A 19-year old white man who was struck in the face during a basketball game had a mucosal laceration of the buccal sulcusjust lateral to the secondmolar. He was seenwhen this area failed to heal after several weeks and developed into an ulcerative lesion. The patient was examined by his dentist, who performed a biopsy on the area. The clinical impression was that the
7114136229
212
lesion representeda pyogenic granuloma. The initial pathologic diagnosis, however, was low-grade (grade I/III) spindle cell sarcoma consistent with leiomyosarcoma. Because of this diagnosis, the patient underwent further examination. A chest x-ray film was unremarkable and a Panorex radiograph and mandibular magnetic resonance imaging showed no evidence of bony abnormality. One month after biopsy the patient underwent reexcision of the biopsy site and the surrounding tissue. The defect was closedwith a buccal flap. Residual tumor was not identified, and postoperative healing was uneventful. The patient remains free of diseaseat 8 months’ follow-up. RESULTS The biopsy consisted of a mass of tan soft tissue measuring 1.5 cm in greatest dimension. Microscopic evaluation of this buccal mucosal biopsy revealed the presence of a nodular invasive and sarcomatousappearing spindle cell proliferation within the deep submucosa (Fig. 1). It infiltrated or obliterated associated skeletal muscle (Fig. 2). The involved mucosa was extensively ulcerated and was covered with a small amount of fibrinopurulent exudate. The adjacent uninvolved mucosa showed marked chronic inflammation consisting of dense infiltrates of plasma cells. The nodular tumorlike mass was composed of a proliferation of monotonous appearing spindle cells that displayed elongated plump vesicular nuclei with blunt ends and one or two small but distinct nucleoli (Fig. 3). They showed moderate amounts of eosinophilic cytoplasm with ill-defined cell borders and
Volume 74
Posttraumatic
spindle cell nodule
213
Number 2
Fig. 1. Invasive and sarcomatous-appearingspindle cell proliferation in deep submucosa.Surface is ulcerated and composedof edematousgranulation tissue that blends imperceptibly with deep-seatedlesion. (Hemotoxylin-eosin stain; magnification X2.)
Fig. 2. Tumorlike proliferation of spindle cells obliterating skeletal muscle at deep aspectsof buccal mucosal biopsy specimen.Arrows show small clusters of degenerating muscle fibers. (Hemotoxylin-eosin stain; magnification X 10.) formed intersecting fascicles that were haphazardly arranged but lacked a storiform pattern (Fig. 4). A delicate network of small capillaries within the lesion was somewhat obscured by the densely arranged fascicles of spindle cells. No collagenization was identifiable. A relatively prominent chronic inflammatory cell infiltrate consisting largely of plasma cells and small numbers of lymphocytes and mast cells was evident throughout the lesion. Moderate numbers of mitoses were identified within the spindle cell proliferation, but none appeared atypical. Small foci of hemorrhage were noted, and the presence of extrava-
sated red blood cells in areas imparted a Kaposi’s sarcoma-like appearance. No necrosis was within the nodule and no polarizable foreign material was identified on examination under polarized light. The spindled areas in the deeper aspects of the biopsy blended gradually and imperceptibly with the overlying loosely organized and edematous granulation tissue within which spindle cells similar in appearance to those found in the deeper aspects of the biopsy were identified. The lesion appeared to have been incompletely excised. Immunohistochemical studies performed with a
214
Zellers, Bicket, and Parker
ORAL SURG ORAL MED ORAL PATHOL August 1992
Fig. 3. Proliferating spindle cells show elongated vesicular nuclei with blunt ends. Mitoses (arrows) are fairly prominent. (Hemotoxylin-eosin stain; magnification x40.)
Fig. 4. Proliferating spindle cells form haphazardly arranged intersecting fascicles and bundles in deep submucosa, simulating sarcoma. (Hemotoxylin-eosin stain; magnification X10.) limited panel of monoclonal antibodies revealed that some of the spindle cells expressed muscle-specific actin (HHF-35). The spindle cells lacked expression
of cytokeratin (AEl-3, a marker of epithelial differentiation), Factor VIII-related antigen (an endothelial cell marker), and HMB-45 (an antimelanomaspecific antigen). Initial pathologic diagnosis was low-grade sarcoma consistent with leiomyosarcoma. On review of the biopsy by another pathologist and two consultants with expertise in soft tissue tumors, the lesion was believed to be consistent with a benign spindle cell nodule
rather than a sarcoma.
The reexcision consisted of a portion of pink-tan mucosa measuring 2.2 x 1.3 X 1.1 cm in greatest dimension. The mucosal surface was smooth, and no tumor was grossly identified. Microscopic examination showedscar formation with fibrosis, mild chronic inflammation and occasional suture granulomas at the site of the previous biopsy. A spindle cell proliferation was not identified. DISCUSSION
Posttraumatic spindle cell nodules involving the oral cavity have not to our knowledge been previously described. The lesion we report is histologically sim-
Posttraumatic
Volume 74 Number 2
ilar to that described by Proppe et al.’ as postoperative spindle cell nodules of the genitourinary tract. These authors mentioned a similar-appearing nodule involving a tooth socket after tooth extraction. Thus apparently both operative and nonoperative trauma may result in similar pseudosarcomatous proliferations. Features distinguishing this lesion from nodular fasciitis, another rare benign pseudosarcomatousprocessthat may arise in the oral cavity, are the lack of myxomatous stroma or foci of cystic degeneration in posttraumatic spindle cell nodules and the cytologic features of the proliferating cells, which in nodular fasciitis usually have S-shaped or wavy nuclei with pointed ends rather than the elongated vesicular forms with blunt ends found in the lesion we described.2 Additionally, nodular fasciitis typically arises spontaneously.*,3 Unlike postoperative or posttraumatic spindle cell nodules, malignant sarcomatous neoplasms(e.g., leiomyosarcoma or Kaposi’s sarcoma) tend to arise spontaneously, without a history of trauma, and they are rarely cured by incomplete excision.’ Rare spindle cell variants of squamouscell carcinoma and melanoma that may have sarcomatous appearancescan in most instances be differentiated from posttraumatic spindle cell nodules by both cytologic features and by immunohistochemical studies.4,5 Squamous cell carcinoma typically expressescytokeratin, and melanoma cells usually expressS- 100 protein and/or HMB-45.@ Kaposi’s sarcoma cells may expressFactor VIII-related antigen9 The spindle cells in the lesion we described were negative for these antigens. The histologic features characterizing the benignity of posttraumatic spindle cell nodules are the lack of necrosis, the cytologic monotony of the proliferating cells, and the lack of atypical mitotic figures. Additionally, sarcomas (i.e., leiomyosarcomas) tend to show more orderly arrangement of their spindle cells in fascicles or bundles than was found in the lesion we described.tO,‘l The histogenesisof postoperative or posttraumatic spindle cell nodules has not been clearly elucidated. Limited ultrastructural studies performed on a postoperative spindle cell nodule of the genitourinary tract suggestthat the proliferating spindled cells are fibroblasts.’ The possibility that the proliferating cells may be myofibroblasts or smooth muscle cells or an admixture of these cell types is suggestedby the reactivity of the spindle cells in the lesion described here with HHF-35. This antigen is expressed by smooth muscle cells and may be expressed by myofibro-
spindle cell nodule
215
blasts.‘* Additional ultrastructural and immunohistochemical studies would be necessaryto define fully the cytogenesis of these lesions. Both benign spindle cell proliferations and sarcomas occur rarely in the oral cavity.‘, 3,‘I Becauseof differences in the therapeutic approach when a benign or a malignant lesion is treated (i.e., simple excision vs wide resection with or without adjunctive postoperative chemotherapy and/or radiation therapy), it is essential that the correct diagnosis be made. Careful correlation of the pathologic findings with the clinical findings should obviate misdiagnosis of a spindle cell proliferation in the oral cavity. We acknowledgeDr. Stacy E. Mills (University of Virginia Health SciencesCenter,Charlottesville,Va.) andDr. Juan Rosai (Yale University, Departmentof Pathology, NewHaven,Corm.)asconsultantsandsourcesof reference. REFERENCES 1. Proppe KH, Scully RE, Rosai J. Post-operative spindle cell nodules of genitourinary tract resembling sarcomas. Am J Surg Path01 1984;8:101-8. 2. Werning JT. Nodular fasciitis of the orofacial region. ORAL SURG URAL MED ORAL PATHOL 1979;48:441-6. -
3. Dahl I. Jarlstedt J. Nodular fasciitis in the head and neck. Acta Otolaryngol 1980;90:152-9. 4. Leventon GS, Evans HL. Sarcomatoid squamous cell carcinoma of the mucous membranes of the head and neck: a clinicopathologic study of 20 cases.Cancer 1981;48:944-1003. 5. Reiman HM, Goellner JR, Woods JE, Mixter RC. Desmoplastic melanoma of the head and neck. Cancer 1987;60:226974. 6. Nagle R. Intermediate
filaments. Am J Clin Path01 1989;91:(suppl 1):514-g. 7. Chandrasoma PT, Martin SE. Primary mucosal malignant melanoma: an immunohistochemical study of 12 cases with comparison to cutaneous and metastatic melanomas. Hum Path01 1986;20:269-72. 8. Gown AM, Vogel AM, Hoak D, Gough F, McNutt MA. Monoclonal antibodies specific for melanocytic tumors distinguish subpopulations of melanocytes. Ann J Path01 1986;123:195-203. 9. Leader M, Collins M, Pate1 J, Henry K. Staining for factor VIII-related antigen and Ufex europeuus agglutinin (UEA-1) in 230 tumors: an assessmentof their specificity for angiosarcomas and Kaposi’s sarcoma. Histopathology 1986;10:115362.
10. Enzinger FM, Weiss SW. Soft tissue tumors. 2nd ed. St Louis: CV Mosby, 1988:407-g. Il. Haedicke G, Kaban LB. Smooth muscle tumors of the oral cavity. Plast Reconstr Surg 1988;81:264-9. 12. Rangdaeng S, Truong LD. Comparative immunohistochemical staining for desmin and muscle-specific actin. Am J Clin Path01 1991;96:32-45. Reprint requests:
Robin A. Zellers, MD Department of Pathology Akron City Hospital 525 E. Market St. Akron, OH 44309
G. Parker, MD, Akron, Ohio
DEPARTMENTS
GENERAL
OF PATHOLOGY
AND
PLASTIC
SURGERY,
AKRON
MEDICAL
CENTER
A benign posttraumatic spindle cell proliferation arising at a site of laceration in the buccal mucosa of a 19-year old man is described. This lesion, which histologically mimicked a leiomyosarcoma, appears to represent a reactive process similar to that described as postoperative spindle cell nodules of the genitourinary tract. Reexcision of the area 1 month after biopsy revealed only scar formation and mild chronic inflammation. Recognition of this type of benign spindle cell proliferation at traumatized sites in the oral cavity is important if misdiagnosis and subsequent aggressive therapy is to be avoided. (ORAL SURC ORAL MED ORAL PATHOL 1992;74:212-5)
D
iagnostic difficulties may be encountered in the histologic interpretation of proliferative spindle cell lesions in any body site. Pseudoneoplastic proliferations may especially represent diagnostic pitfalls in that they clinically and histologically may be mistaken for malignant tumors. Benign postoperative spindle cell nodules resembling sarcomas of the genitourinary tract have recently been described as a distinct clinicopathologic entity. These nodules represent benign reactive spindle cell lesions that are distinct histologically from other types of benign proliferative lesions of soft tissues such as nodular fasciitis. They may be mistaken histologically for leiomyosarcoma or Kaposi’s sarcoma.’ We describe a similar benign spindle cell lesion that developed in the oral cavity after trauma to the buccal mucosa. Recognition of posttraumatic spindle cell nodules is important if the potentially serious consequences of misdiagnosis of malignancy are to be avoided. CASE REPORT A 19-year old white man who was struck in the face during a basketball game had a mucosal laceration of the buccal sulcusjust lateral to the secondmolar. He was seenwhen this area failed to heal after several weeks and developed into an ulcerative lesion. The patient was examined by his dentist, who performed a biopsy on the area. The clinical impression was that the
7114136229
212
lesion representeda pyogenic granuloma. The initial pathologic diagnosis, however, was low-grade (grade I/III) spindle cell sarcoma consistent with leiomyosarcoma. Because of this diagnosis, the patient underwent further examination. A chest x-ray film was unremarkable and a Panorex radiograph and mandibular magnetic resonance imaging showed no evidence of bony abnormality. One month after biopsy the patient underwent reexcision of the biopsy site and the surrounding tissue. The defect was closedwith a buccal flap. Residual tumor was not identified, and postoperative healing was uneventful. The patient remains free of diseaseat 8 months’ follow-up. RESULTS The biopsy consisted of a mass of tan soft tissue measuring 1.5 cm in greatest dimension. Microscopic evaluation of this buccal mucosal biopsy revealed the presence of a nodular invasive and sarcomatousappearing spindle cell proliferation within the deep submucosa (Fig. 1). It infiltrated or obliterated associated skeletal muscle (Fig. 2). The involved mucosa was extensively ulcerated and was covered with a small amount of fibrinopurulent exudate. The adjacent uninvolved mucosa showed marked chronic inflammation consisting of dense infiltrates of plasma cells. The nodular tumorlike mass was composed of a proliferation of monotonous appearing spindle cells that displayed elongated plump vesicular nuclei with blunt ends and one or two small but distinct nucleoli (Fig. 3). They showed moderate amounts of eosinophilic cytoplasm with ill-defined cell borders and
Volume 74
Posttraumatic
spindle cell nodule
213
Number 2
Fig. 1. Invasive and sarcomatous-appearingspindle cell proliferation in deep submucosa.Surface is ulcerated and composedof edematousgranulation tissue that blends imperceptibly with deep-seatedlesion. (Hemotoxylin-eosin stain; magnification X2.)
Fig. 2. Tumorlike proliferation of spindle cells obliterating skeletal muscle at deep aspectsof buccal mucosal biopsy specimen.Arrows show small clusters of degenerating muscle fibers. (Hemotoxylin-eosin stain; magnification X 10.) formed intersecting fascicles that were haphazardly arranged but lacked a storiform pattern (Fig. 4). A delicate network of small capillaries within the lesion was somewhat obscured by the densely arranged fascicles of spindle cells. No collagenization was identifiable. A relatively prominent chronic inflammatory cell infiltrate consisting largely of plasma cells and small numbers of lymphocytes and mast cells was evident throughout the lesion. Moderate numbers of mitoses were identified within the spindle cell proliferation, but none appeared atypical. Small foci of hemorrhage were noted, and the presence of extrava-
sated red blood cells in areas imparted a Kaposi’s sarcoma-like appearance. No necrosis was within the nodule and no polarizable foreign material was identified on examination under polarized light. The spindled areas in the deeper aspects of the biopsy blended gradually and imperceptibly with the overlying loosely organized and edematous granulation tissue within which spindle cells similar in appearance to those found in the deeper aspects of the biopsy were identified. The lesion appeared to have been incompletely excised. Immunohistochemical studies performed with a
214
Zellers, Bicket, and Parker
ORAL SURG ORAL MED ORAL PATHOL August 1992
Fig. 3. Proliferating spindle cells show elongated vesicular nuclei with blunt ends. Mitoses (arrows) are fairly prominent. (Hemotoxylin-eosin stain; magnification x40.)
Fig. 4. Proliferating spindle cells form haphazardly arranged intersecting fascicles and bundles in deep submucosa, simulating sarcoma. (Hemotoxylin-eosin stain; magnification X10.) limited panel of monoclonal antibodies revealed that some of the spindle cells expressed muscle-specific actin (HHF-35). The spindle cells lacked expression
of cytokeratin (AEl-3, a marker of epithelial differentiation), Factor VIII-related antigen (an endothelial cell marker), and HMB-45 (an antimelanomaspecific antigen). Initial pathologic diagnosis was low-grade sarcoma consistent with leiomyosarcoma. On review of the biopsy by another pathologist and two consultants with expertise in soft tissue tumors, the lesion was believed to be consistent with a benign spindle cell nodule
rather than a sarcoma.
The reexcision consisted of a portion of pink-tan mucosa measuring 2.2 x 1.3 X 1.1 cm in greatest dimension. The mucosal surface was smooth, and no tumor was grossly identified. Microscopic examination showedscar formation with fibrosis, mild chronic inflammation and occasional suture granulomas at the site of the previous biopsy. A spindle cell proliferation was not identified. DISCUSSION
Posttraumatic spindle cell nodules involving the oral cavity have not to our knowledge been previously described. The lesion we report is histologically sim-
Posttraumatic
Volume 74 Number 2
ilar to that described by Proppe et al.’ as postoperative spindle cell nodules of the genitourinary tract. These authors mentioned a similar-appearing nodule involving a tooth socket after tooth extraction. Thus apparently both operative and nonoperative trauma may result in similar pseudosarcomatous proliferations. Features distinguishing this lesion from nodular fasciitis, another rare benign pseudosarcomatousprocessthat may arise in the oral cavity, are the lack of myxomatous stroma or foci of cystic degeneration in posttraumatic spindle cell nodules and the cytologic features of the proliferating cells, which in nodular fasciitis usually have S-shaped or wavy nuclei with pointed ends rather than the elongated vesicular forms with blunt ends found in the lesion we described.2 Additionally, nodular fasciitis typically arises spontaneously.*,3 Unlike postoperative or posttraumatic spindle cell nodules, malignant sarcomatous neoplasms(e.g., leiomyosarcoma or Kaposi’s sarcoma) tend to arise spontaneously, without a history of trauma, and they are rarely cured by incomplete excision.’ Rare spindle cell variants of squamouscell carcinoma and melanoma that may have sarcomatous appearancescan in most instances be differentiated from posttraumatic spindle cell nodules by both cytologic features and by immunohistochemical studies.4,5 Squamous cell carcinoma typically expressescytokeratin, and melanoma cells usually expressS- 100 protein and/or HMB-45.@ Kaposi’s sarcoma cells may expressFactor VIII-related antigen9 The spindle cells in the lesion we described were negative for these antigens. The histologic features characterizing the benignity of posttraumatic spindle cell nodules are the lack of necrosis, the cytologic monotony of the proliferating cells, and the lack of atypical mitotic figures. Additionally, sarcomas (i.e., leiomyosarcomas) tend to show more orderly arrangement of their spindle cells in fascicles or bundles than was found in the lesion we described.tO,‘l The histogenesisof postoperative or posttraumatic spindle cell nodules has not been clearly elucidated. Limited ultrastructural studies performed on a postoperative spindle cell nodule of the genitourinary tract suggestthat the proliferating spindled cells are fibroblasts.’ The possibility that the proliferating cells may be myofibroblasts or smooth muscle cells or an admixture of these cell types is suggestedby the reactivity of the spindle cells in the lesion described here with HHF-35. This antigen is expressed by smooth muscle cells and may be expressed by myofibro-
spindle cell nodule
215
blasts.‘* Additional ultrastructural and immunohistochemical studies would be necessaryto define fully the cytogenesis of these lesions. Both benign spindle cell proliferations and sarcomas occur rarely in the oral cavity.‘, 3,‘I Becauseof differences in the therapeutic approach when a benign or a malignant lesion is treated (i.e., simple excision vs wide resection with or without adjunctive postoperative chemotherapy and/or radiation therapy), it is essential that the correct diagnosis be made. Careful correlation of the pathologic findings with the clinical findings should obviate misdiagnosis of a spindle cell proliferation in the oral cavity. We acknowledgeDr. Stacy E. Mills (University of Virginia Health SciencesCenter,Charlottesville,Va.) andDr. Juan Rosai (Yale University, Departmentof Pathology, NewHaven,Corm.)asconsultantsandsourcesof reference. REFERENCES 1. Proppe KH, Scully RE, Rosai J. Post-operative spindle cell nodules of genitourinary tract resembling sarcomas. Am J Surg Path01 1984;8:101-8. 2. Werning JT. Nodular fasciitis of the orofacial region. ORAL SURG URAL MED ORAL PATHOL 1979;48:441-6. -
3. Dahl I. Jarlstedt J. Nodular fasciitis in the head and neck. Acta Otolaryngol 1980;90:152-9. 4. Leventon GS, Evans HL. Sarcomatoid squamous cell carcinoma of the mucous membranes of the head and neck: a clinicopathologic study of 20 cases.Cancer 1981;48:944-1003. 5. Reiman HM, Goellner JR, Woods JE, Mixter RC. Desmoplastic melanoma of the head and neck. Cancer 1987;60:226974. 6. Nagle R. Intermediate
filaments. Am J Clin Path01 1989;91:(suppl 1):514-g. 7. Chandrasoma PT, Martin SE. Primary mucosal malignant melanoma: an immunohistochemical study of 12 cases with comparison to cutaneous and metastatic melanomas. Hum Path01 1986;20:269-72. 8. Gown AM, Vogel AM, Hoak D, Gough F, McNutt MA. Monoclonal antibodies specific for melanocytic tumors distinguish subpopulations of melanocytes. Ann J Path01 1986;123:195-203. 9. Leader M, Collins M, Pate1 J, Henry K. Staining for factor VIII-related antigen and Ufex europeuus agglutinin (UEA-1) in 230 tumors: an assessmentof their specificity for angiosarcomas and Kaposi’s sarcoma. Histopathology 1986;10:115362.
10. Enzinger FM, Weiss SW. Soft tissue tumors. 2nd ed. St Louis: CV Mosby, 1988:407-g. Il. Haedicke G, Kaban LB. Smooth muscle tumors of the oral cavity. Plast Reconstr Surg 1988;81:264-9. 12. Rangdaeng S, Truong LD. Comparative immunohistochemical staining for desmin and muscle-specific actin. Am J Clin Path01 1991;96:32-45. Reprint requests:
Robin A. Zellers, MD Department of Pathology Akron City Hospital 525 E. Market St. Akron, OH 44309
