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An Official Publication of the Indian Association of Oral and Maxillofacial Pathologists

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Year : 2023  |  Volume : 27  |  Issue : 5  |  Page : 33-37

Undifferentiated pleomorphic sarcoma of the floor of mouth: A rare case

Department of Pathology, Bhagwan Mahaveer Cancer Hospital and Research Center, Jaipur, Rajasthan, India

Date of Submission02-Apr-2021
Date of Decision20-Oct-2022
Date of Acceptance06-Dec-2022
Date of Web Publication04-Feb-2023

Correspondence Address:
Praveena Vyas
Department of Pathology, Bhagwan Mahaveer Cancer Hospital and Research Center, Jaipur - 302 017, Rajasthan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jomfp.jomfp_107_21

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Undifferentiated pleomorphic sarcoma (UPS) previously called as malignant fibrous histiocytoma comprises a group of high-grade pleomorphic sarcomas that cannot be otherwise classified and considered as a diagnosis of exclusion. In the head neck region, UPS is extremely rare and accounts for 3% of all the undifferentiated pleomorphic sarcomas. Some of the reported sites include maxilla, mandible, buccal mucosa, temperomandibular fossa, tongue, gingiva, paranasal sinuses, salivary glands, and retro-orbital soft tissue. Undifferentiated pleomorphic sarcoma of the floor of the mouth is very rare. To our knowledge, only one case has been reported earlier. We report the second case of undifferentiated pleomorphic sarcoma of the floor of mouth.

Keywords: Undifferentiated pleomorphic sarcoma, floor of mouth, malignant fibrous histiocytoma, rare tumor, sarcoma

How to cite this article:
Sharma A, Vyas P, Agarwal D. Undifferentiated pleomorphic sarcoma of the floor of mouth: A rare case. J Oral Maxillofac Pathol 2023;27, Suppl S1:33-7

How to cite this URL:
Sharma A, Vyas P, Agarwal D. Undifferentiated pleomorphic sarcoma of the floor of mouth: A rare case. J Oral Maxillofac Pathol [serial online] 2023 [cited 2023 Mar 21];27, Suppl S1:33-7. Available from: https://www.jomfp.in/text.asp?2023/27/5/33/369164

   Introduction Top

Undifferentiated pleomorphic sarcoma (UPS) is a soft tissue sarcoma composed of undifferentiated mesenchymal cells with fibrohistiocytic morphology without lineage specific differentiation representing a diagnosis of exclusion in the current World Health Organization.[1],[2],[3] In the past, most of these cases of (UPSs) were diagnosed as pleomorphic malignant fibrous histiocytomas, a term that has been kept as being synonymous with UPS in the current WHO classification.[4]

The UPSs represent about 5% of all soft tissue sarcomas in adults and occur more commonly in the extremities, mainly lower limbs, of patients during the 6th and 7th decades of life.[2] Microscopically, this group of lesions shows a heterogeneous pattern with frequent pleomorphism and aberrant giant cells.[3] The immunohistochemical (IHC) findings are nonspecific, showing that it is only a mesenchymal tumor, because the tumor cells are positive for vimentin.[3] Other immunomarkers are rarely positive.[3] In oral cavity, UPS seems to be extremely rare.[5] Some of the reported sites include maxilla, mandible, buccal mucosa, temperomandibular fossa, tongue, gingiva, paranasal sinuses, salivary glands, and retro-orbital soft tissues.[6] UPS is an aggressive tumor, with a high potential of metastasis to other parts of the body.[7] Repeated recurrences are common in patients with UPS before a confirmatory diagnosis is made.[7] Furthermore, the prognosis may become poor due to distant metastasis.[7] Therefore, correct diagnosis and initial treatment are extremely important for such sarcomas.[7]

The histopathologists often encounter such mesenchymal neoplasms within the oral cavity. There have been previous published reports of synovial sarcomas, extraskeletal Ewing's sarcoma arising in the floor of mouth (FOM). According to the available literature, only one case of an undifferentiated pleomorphic sarcoma of the FOM had been reported earlier.[5]

Here, we report the second case of an undifferentiated pleomorphic sarcoma arising in the FOM masquerading as oral squamous cell carcinoma (SCC) in its clinical presentation and being diagnosed as a poorly differentiated SCC on incisional biopsy to be proven later as UPS after surgical resection by microscopy and IHC.

   Case Report Top

A 50-year-old female reported at our institute with the complaint of a persistent, non-healing ulcer on the right FOM since last 6 months which rapidly increased in size in the last 1.5 months. Her medical history and family history were unremarkable. A month beforehand, an incisional biopsy of this ulcer was done and reported as poorly differentiated SCC. However, the ulcer was persistent, progressive, caused pain, and difficulty in mastication.

Intraoral examination revealed the presence of a unilateral, single, and easily bleeding ulcer with heaped up edges and necrotic base with surrounding induration, measuring 4 × 3 cm in size in the right FOM extending from the canine to the first right molar and reaching upto midline. Clinically, nodes were palpable at the level of right level IB and II neck regions. An incisional biopsy block was also reviewed. The biopsy showed ovoid to spindloid, pleomorphic epithelial cells infiltrating the soft tissue with focal necrotic areas. Overall morphology was suggestive of poorly differentiated SCC.

The patient was then planned for surgery and underwent composite resection (wide local excision of the right FOM, adjacent tongue, and marginal mandibulectomy) with right modified neck dissection and the left supraomohyoid neck dissection. On gross examination, an ulceroproliferative lesion was identified measuring 4.5 × 3 × 1.5 cm in the right FOM. On cut section, it was firm, fleshy, pale white, and poorly circumscribed with irregular borders. On microscopy, the tumor showed a densely cellular, high grade, and invasive malignant mesenchymal neoplasm displaying tumor cells arranged in sheets, interlacing fascicles, and storiform pattern [Figure 1]. The tumor cells were haphazardly arranged, pleomorphic, spindloid to ovoid, with ill-defined cell borders, scanty to moderate pale granular cytoplasm, strikingly pleomorphic, multilobated, and vesicular to coarse nuclei with prominent eosinophilic nucleoli. The intervening stroma was fibromyxoid. Extensive necrosis was identified (30 to 50%). Lymphovascular invasion and perineural invasion were not evident. Brisk atypical mitosis 10 to15/10 high power fields were identified [Figure 2]. There was no evidence of myogenic or heterologous differentiation. Overall morphology was suggestive of high-grade malignant mesenchymal neoplasm. Marker studies were advised for exact histogenesis. On IHC analysis, the tumor was labeled as undifferentiated pleomorphic sarcoma, as the neoplasm showed positivity for vimentin and CD-163 [Figure 3] and [Figure 4]. The tumor was negative for desmin, myogenin, caldesmon, and pancytokeratin.
Figure 1: Short fascicles and storiform arrangement of pleomorphic spindle cells. (H&E X 10)

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Figure 2: Bizarre pleomorphic spindle cells (H&E X 10)

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Figure 3: Vimentin strongly positive

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Figure 4: Focally positive CD 163

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   Discussion Top

SCC and lymphoma are the most common cancers of head and neck representing 80%–90% of the total cases, while sarcomas are relatively rare in this area, representing between 1% and 10% of the neoplasms.[8] Undifferentiated high-grade pleomorphic sarcoma is currently a diagnosis of exclusion and represents 5% of soft tissue sarcomas in adults.[2],[9] It is a soft tissue sarcoma composed of undifferentiated mesenchymal cells.[1] It usually occurs in lower extremities.[8] UPS is characteristically a tumor of late adult life, with most cases occurring in persons between the ages of 50 and 70 years.[10] Tumors in children are exceedingly rare, and this diagnosis should always be made with caution in patients less than 20 years of age.[11] Approximately, two-thirds occur in men, and whites are affected more often than blacks or Asians.[11] The tumor occurs most frequently in the lower extremity especially thighs.[11] Its location in the head and neck is rare.[12] The most frequent location in head and neck is the neck and parotid gland, followed by the scalp, face, anterior skull base, and orbit. Their presence in oral cavity is extremely rare.[12]

There have been reports of predisposing factors such as history of recurrent trauma, surgery, radiation, fractures, osteonecrosis, Paget's disease, non-ossifying fibroma, and fibrous dysplasia.[13]

Clinically, the most common symptom is the presence of a mass of progressive and rapid growth that may be associated with nonspecific symptoms such as pain and paresthesia of the compromised site.[12] Imaging studies like the computed tomography and magnetic resonance imaging usually reveal a heterogeneously enhancing, lobulated soft tissue mass with adjacent soft tissue, and bone extension. The gross appearance is typically heterogeneous with areas of gelatinous firm and fleshy components admixed with areas of necrosis and cystic hemorrhagic change.[10] On microscopy, UPS shows an intratumoral and intertumoral diversity.[10] There is high degree of nuclear pleomorphism often with multinucleated bizzare giant cells with dense hyperchromatic nuclei.[10] The non-pleomorphic component has variable cytomorphology ranging from spindle to more epitheloid cells.[10] The spindle cells are arranged in storiform pattern or intersect in short fascicles showing modest amount of amphophilic to pale eosinophilic cytoplasm.[10] The nuclei are fusiform with open or vesicular chromatin and inconspicuous nucleoli.[10] The epitheloid/histiocytic cells have moderate to abundant eosinophilic cytoplasm and eccentric nuclei.[10] Occasional osteoclast like giant cells may be seen scattered.[10] The extracellular stroma varies from myxoid to more often densely sclerotic.[10] Areas of necrosis and increased mitotic activity including atypical mitotic figures are present.[10]

Neville et al.[14] described various histological subtypes including storiform, pleomorphic, myxoid, giant cell, angiomatoid, and inflammatory.

Here are some of the key features of the various histological subtypes of UPS [Table 1]:[7],[14]
Table 1: Histopathological Subtypes of UPS

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Many mesenchymal and non-mesenchymal neoplasms can be included in the differential diagnosis of UPS. The mesenchymal neoplasms that mimic UPS are pleomorphic liposarcoma, pleomorphic leiomyosarcoma, pleomorphic rhabdomyosarcoma, pleomorphic malignant nerve sheath tumor, and extraskeletal osteosarcoma.[11] The only criterion for rendering a diagnosis of pleomorphic liposarcoma is the recognition of multivacuolated pleomorphic lipoblasts.[11] Pleomorphic liposarcoma shows focal S100 positivity in the signet ring or multivacuolated tumor lipoblasts.[15] Pleomorphic leiomyosarcoma is composed of cells in fascicular arrangement showing deeply eosinophilic cytoplasm blunt ended nuclei with perinuclear vacuoles.[11] These tumors are positive for alpha smooth muscle actin, H caldesmon, and vimentin.[15] Pleomorphic rhabdomyosarcoma is recognized by the presence of large cells with eosinophilic cytoplasm and cross striations, which can be confirmed by the IHC demonstration of skeletal muscle differentiation.[11] These tumors are globally positive for desmin and muscle specific actin.[15] In addition, they also express myoglobin and myogenin, the proteins expressed by skeletal muscle.[15] Myogenin is strictly limited to the nuclei.[15] Myoglobin expression assumes importance in pleomorphic neoplasms as de differentiated leiomyosarcoma can express desmin and actin but are devoid of myoglobin.[15] A definitive diagnosis of pleomorphic malignant peripheral nerve sheath tumor can be difficult unless the pleomorphic sarcoma clearly arises from a benign nerve sheath tumor or arises from a peripheral nerve in a patient with type-1 neurofibromatosis.[11] These tumors are capable of diffuse S-100 expression with or without CD 56.[15] The only criterion for recognizing extraskeletal osteosarcoma is the production of osteoid or bone by cytologically malignant cells.[11] The non-mesenchymal neoplasms resembling UPS are sarcomatoid carcinoma, melanoma, and anaplastic lymphoma. It can be exceedingly difficult to distinguish a UPS from a sarcomatoid carcinoma.[11] A battery of epithelial markers including broad-spectrum, low and high-molecular-weight cytokeratins is required, but equivocal results are not uncommon for several reasons.[11] First, not all sarcomatoid carcinomas show the immunohistochemical expression of epithelial markers.[11] Second, virtually any type of sarcoma, including UPS, can on occasion express cytokeratins.[11] Strong and diffuse cytokeratin expression, especially with multiple antibodies, strongly supports a diagnosis of sarcomatoid carcinoma, as does the recognition of an intraepithelial/intramucosal dysplastic component.[11] p63 can also have a role in this IHC work-up.[11] Although p63 is frequently expressed in a variety of sarcomatoid carcinomas, it is actually very rarely expressed in soft tissue tumors.[11] It should also be kept in mind that melanoma, and anaplastic lymphoma can on occasion mimic UPS; a panel of markers including melanocytic markers such as HMB45 and Melan A, CD30, and ALK1 can help resolve these issues.[11] Following the exclusion of the aforementioned scenarios, one is left with UPS as a diagnosis of exclusion.

Immunohistochemically, the tumor cells show strong immunoreactivity for vimentin and strong cytoplasmic staining for CD 68 and CD 163, a histiocyte marker.[7] They are consistently negative for other lineage specific markers.[7]

Once diagnosed, multimodality therapeutic approach combining surgery, external beam radiation therapy chemotherapy drugs like doxorubicin tailored according to the patient is the only option left.[10] The prognosis of UPS is dismal.[11] The vast majority of UPS are high-grade lesions having a local recurrence rate ranging from 19–31%, a metastatic rate of 31–35%, and a 5-year survival of 65–70%.[11] Both local recurrence and distant metastases often develop within 12–24 months of diagnosis.[11] Only a minority of patients develop metastases after 5 years, with the common metastatic sites being lung (90%), bone (8%), and liver (1%).[11] Regional lymph node metastases are decidedly uncommon.[11] The predictors of poor outcome are male sex, advanced age, underlying systemic illness, large primary tumors, tumors arising in the bone and deep seated tumors, high-grade tumors, myogenic differentiation, and desmin positivity.[10]

   Conclusion Top

In summary, UPS is rare in oral cavity and it can be easily misdiagnosed as poorly differentiated SCC or sarcomatoid carcinoma. As per our knowledge, very few cases of UPS of the floor of mouth have been described in the literature. The purpose of this case report was to add to the existing knowledge about this rare entity in the floor of mouth.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Vuity D, Bogdan S, Csurgay K, Sapi Z, Nemeth Z. Malignant fibrous histiocytoma/undifferentiated high-grade pleomorphic sarcoma of the maxillary sinus: Report of a case and review of the literature. Pathol Oncol Res 2013;19:605-9.  Back to cited text no. 1
Fletcher CDM, Vandenberg E, Molenaar WM. World Health Organization Classification of Tumors. Pathology and Genetics of Tumours of Soft Tissue and Bone. IARC lyon; 2002. p. 120.  Back to cited text no. 2
Fletcher CD. The evolving classification of soft tissue tumours: An update based on the new WHO classification. Histopathology 2006;48:3-12.  Back to cited text no. 3
Dei Tos AP. Classification of pleomorphic sarcomas: Where are we now?. Histopathology 2006;48:51-62.  Back to cited text no. 4
Alfredo E, de Pádua JM, Vicentini EL, Marchesan MA, Comelli Lia RC, da Cruz Perez DE, et al. Oral undifferentiated high-grade pleomorphic sarcoma: Report of a case. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105:e37-40.  Back to cited text no. 5
Varma K, Mandal S, Jain S, Mandal AK. An ulcero proliferative growth in the gingiva: A cytological approach to the diagnosis. Cytopathology 2007;18:376-9.  Back to cited text no. 6
Vijayalakshmi D, Fathima S, Ramakrishnan K, Devi M. Malignant fibrous histiocytoma of the gingiva. BMJ Case Rep 2012;2012:bcr2012007400.  Back to cited text no. 7
Bentz BG, Singh B, Woodruff J, Brennan M, Shah JP, Kraus D. Head and neck soft tissue sarcomas: A multivariate analysis of outcomes. Ann Surg Oncol 2004;11:619-28.  Back to cited text no. 8
Müller-Richter UD, Kohlhof JK, Reichert TE, Roldán JC. Undifferentiated pleomorphic sarcoma of the orbital region. Br J Oral Maxillofac Surg 2008;46:325-7.  Back to cited text no. 9
Miettinen M, Fetsch John F, Antonescu Cristina R, Folpe Andrew L, Wakely Paul E. AFIP Atlas of Tumor Pathology Fourth Series, Fascicle 20. Tumors of the Soft Tissues. American Registry of Pathology; 2014. p203-5.  Back to cited text no. 10
Goldblum JR. An approach to pleomorphic sarcomas: Can we subclassify, and does it matter? Mod Pathol 2014;27(Suppl 1):S39-46.  Back to cited text no. 11
Sepúlveda I, Compan A, Ulloa J, Mucientes P, Vera P, Ascui R, et al. Maxillary undifferentiated high-grade pleomorphic sarcoma: A case report and review of the literature. Case Rep Clin Pathol 2016;4:32-6.  Back to cited text no. 12
Pobirci DD, Bogdan F, Pobirci O, Petcu CA, Roşca E. Study of malignant fibrous histiocytoma: Clinical, statistic and histopatological interrelation. Rom J Morphol Embryol 2011;52:385-8.  Back to cited text no. 13
Neville B, Damm DD, Allen C, Chi A. Textbook of Oral & Maxillofacial Pathology. 2nd ed. Elsevier Publishers; 2002. p. 481.  Back to cited text no. 14
Wick MR. Immunohistochemical approaches to the diagnosis of undifferentiated malignant tumors. Ann Diagn Pathol 2008;12:72-84.  Back to cited text no. 15


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]


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