|Year : 2015 | Volume
| Issue : 2 | Page : 130-133
Undifferentiated pleomorphic sarcoma presenting as a gingival mass: A rare case
BS Sreenivasan1, V Vinod Sankar2, Deepu George Mathew1, Merin George3
1 Department of Oral and Maxillofacial Pathology, Mar Baselios Dental College, Kothamangalam, Kerala, India
2 Department of Oral and Maxillofacial Surgery, Mar Baselios Dental College, Kothamangalam, Kerala, India
3 Department of Oral Medicine and Radiology, Mar Baselios Dental College, Kothamangalam, Kerala, India
|Date of Web Publication||12-Jun-2015|
B S Sreenivasan
Department of Oral and Maxillofacial Pathology, Mar Baselios Dental College, Kothamangalam, Ernakulam, Kerala - 686 691
Source of Support: None, Conflict of Interest: None
Malignant fibrous histiocytoma which was once considered as a tumor of adults, is now being re-classified and subtyped either as a pleomorphic undifferentiated sarcoma or pleomorphic variant of other spindle cell tumors. Only less than 5% of these cases are reported in the head and neck, and its presentation intra-orally is still rarer. Herein, we report a case of gingival swelling in relation to the 16 region, which on microscopic examination showed a histomorphometric pattern of storiform pleomorphic-malignant fibrous histiocytoma. Immunohistochemical studies were done to exclude similar appearing spindle cell neoplasms. The tumor showed focal positivity for pan histiocytic marker, CD68. Based on the histopathological and immunohistochemical profiles, the tumor was diagnosed as undifferentiated pleomorphic sarcoma.
Keywords: Malignant fibrous histiocytoma, pan histiocytic marker, storiform pleomorphic, undifferentiated pleomorphic sarcoma
|How to cite this article:|
Sreenivasan B S, Sankar V V, Mathew DG, George M. Undifferentiated pleomorphic sarcoma presenting as a gingival mass: A rare case. J NTR Univ Health Sci 2015;4:130-3
|How to cite this URL:|
Sreenivasan B S, Sankar V V, Mathew DG, George M. Undifferentiated pleomorphic sarcoma presenting as a gingival mass: A rare case. J NTR Univ Health Sci [serial online] 2015 [cited 2022 Jan 19];4:130-3. Available from: https://www.jdrntruhs.org/text.asp?2015/4/2/130/158599
| Introduction|| |
Malignant fibrous histiocytoma (MFH) was considered as a tumor of adult life. This tumor was first described by O'brian and Stout and was considered to be derived from histiocytes, which can assume the appearance of fibroblast, known as facultative fibroblast.  But, later studies with tissue lineage markers showed that they are either pleomorphic subtypes of other sarcomas or an undifferentiated pleomorphic sarcoma. 
The common site of occurrence is the extremities involving the metaphysis of long bones. It rarely involves the head and neck region, with 54% of the cases involving nasal cavity and paranasal sinus. Involvement of the oral cavity is rare and accounts to only 3% of the reported cases. ,,, Herein, we report a rare case of intraoral MFH involving the gingiva of region 16 with its immunohistochemistry (IHC) profile.
| Case Report|| |
A 74-year-old female patient reported to the OPD with a complaint of non-tender swelling on the right upper jaws with mobility of the adjacent teeth for the past 3 months. Patient did not have any deleterious habits. Intra oral examination revealed a well-defined unilateral solitary swelling measuring 3 × 2 cm present in relation to 16. Surface appeared ulcerated and bluish pink in color [Figure 1]. On palpation, the swelling was firm, pedunculated, non-tender, non-compressible and non-reducible.
The associated 16 region showed gingival recession, with furcation involvement and grade III mobility. Based on the clinical appearance and behavior, the lesion was provisionally diagnosed as pyogenic granuloma. Intra oral periapical radiograph showed severe interdental bone loss in the 16 region [Figure 2].
|Figure 2: Intraoral periapical radiograph showing bone loss in relation to 16|
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An excision biopsy was performed and a formalin fixed mass of size1.5 × 1.3 × 1.5 cm was received for histopathological examination [Figure 3]. Routine hematoxylin and eosin stained sections showed spindle shaped fibroblast cells arranged in a whorled storiform pattern with many areas showing cellular and nuclear pleomorphism [Figure 4] and [Figure 5]. Many foci showed areas of histiocytic differentiation with multinucleated giant cells and abnormal mitotic figures [Figure 6] and [Figure 7]. These histomorphologic patterns were suggestive of storiform pleomorphic type of malignant fibrous histiocytoma. Due to the presence of more than 20 mitosis in 10 high power fields, cellular pleomorphism and absence of necrosis, the tumor obtained an overall score of 7 and was graded as grade III [Table 1]. 
|Figure 4: Photomicrograph (10×) showing storiform pattern of spindle cell arrangement|
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|Figure 6: Photomicrograph (40×) showing areas of histiocytic differentiation and giant cell formation|
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|Table 1: Histologic Grading System for Spindle Cell Soft Tissue Sarcomas|
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But various other spindle cell neoplasms like spindle cell carcinoma, amelanotic melanomas, pleomorphic rhabdomyosarcomas and leiomyosarcomas can also show similar histologic pattern in routine stains. In order to rule out these differential diagnoses, Immunohistochemistry (IHC) was performed. The tumor cells were negative for pancytokeratin, S100, desmin and smooth muscle actin (SMA). Pan histiocytic marker, CD68 showed positivity in areas with histiocytic differentiation [Figure 8]. Based on the clinical, histopathological and IHC results, the lesion was diagnosed as high grade undifferentiated pleomorphic sarcoma. Patient was referred to a tertiary care oncologic center for further management.
|Figure 8: Photomicrograph (40×) showing areas of histiocytic differentiation positive with CD68|
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| Discussion|| |
MFH is a soft tissue sarcoma, first described in 1964 by O'brian. MFH was considered as the most common soft tissue sarcoma of adults. This diagnosis was considered to be made with caution in persons under the age of 20 years.  Arthur Purdy Stout and colleagues who initially studied the histogenesis of MFH by observing cells cultured from the lesional tissue postulated that these tumors arose from histiocytes and is capable of fibroblastic transformation. He hence called them "facultative fibroblasts".  The widespread use of monoclonal antibodies questioned this histiocytic origin of the tumor. Histiocytic markers like CD68 were seen to be expressed even in melanomas and carcinomas. When many cases previously diagnosed as MFH were re-assessed, majority of these cases were found to be pleomorphic variants of other sarcomas. MFH especially the pleomorphic variant is now considered to be a histomorphologic pattern rather than a true pathologic entity. 
According to the current World health organization (WHO) classification, pleomorphic type of MFH is considered to be either pleomorphic subtypes of other sarcomas or an undifferentiated pleomorphic sarcoma.  These undifferentiated pleomorphic sarcomas are recognized to be formed from primitive multi-potent mesenchymal cell that can differentiate into fibroblastic and histiocytic neoplastic cells.  The diagnosis usually has to be made by exclusion using immunohistochemical markers.  It has been reported that tumors having the histomorphologic pattern of MFH, can express intermediate filaments like keratin, desmin and neurofilaments, but the expression is usually focal. Enzinger and Goldblum had adopted an approach where uniform, intense immunostaining rather than a focal staining is required to reflect specific differentiation. 
The pleomorphic variants of leiomyosarcoma, malignant peripheral nerve sheath tumor, anaplastic carcinoma, rhabdomyosarcomas and liposarcomas can resemble histopathologically like storiform pleomorphic type of MFH.  In our case, the tumor cells were negative for cytokeratin an epithelial marker for anaplastic carcinoma, desmin-a muscle marker, smooth muscle actin-marker for smooth muscle differentiation, S-100-marker for melanoma and neural tumors. Tumor tissue did not show any areas of clear cells or lipoblasts excluding the possibility of being a pleomorphic liposarcoma. The tumor tissue showed focal positivity for pan histiocytic marker, CD68. Similar immunostaining pattern with CD68 has been reported in cases documented as pleomorphic sarcomas.  Since, the tumor cells in our case did not show any uniform intense staining for any of the aforementioned differentiating markers, we diagnosed it finally as undifferentiated pleomorphic sarcoma. Coindre et al., in 1988, graded spindle cell neoplasms based on tumor differentiation, mitosis count and tumor necrosis [Table 1]. Metastasis and patient survival were found to be significantly correlated to the tumor grading.  Based on the histopathological feature and IHC profile, our case was diagnosed and graded as undifferentiated pleomorphic sarcoma of grade III.
According to the follow-up study conducted by Sabesan et al., on 131 cases diagnosed as MFH, those in head and neck area had worse prognosis than that on the extremities and trunk.  Surgical excision is considered as the most successful primary treatment options for these patients. 
| Conclusion|| |
The pathology which was once known as MFH is now better differentiated as either pleomorphic variant of other sarcomas or a pleomorphic sarcoma. Hence, it has become necessary to characterize these tumors with judicious use of IHC markers. Awareness among pathologists and surgeons on re-classification of these tumors will aid in the early diagnosis and appropriate management.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]