|Year : 2012 | Volume
| Issue : 2 | Page : 282-285
Pediatric oral leiomyosarcoma: Rare case report
CV Divyambika1, S Sathasivasubramanian1, CL Krithika1, N Malathi2, D Prathiba3
1 Department of Oral Medicine and Radiology, Sri Ramachandra University, Porur, Chennai - 600118, India
2 Department of Oral Pathology, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai - 600118, India
3 Department of General Pathology, Sri Ramachandra University, Porur, Chennai - 600118, India
|Date of Web Publication||26-Jul-2012|
C V Divyambika
Department of Oral Medicine and Radiology, Faculty of Dental Sciences, Sri Ramachandra University, Porur, Chennai - 600118
Soft tissue sarcomas comprise a group of histologically diverse malignant neoplasms arising from mesenchymal cell lines. Among these, leiomyosarcomas are sarcomas exhibiting smooth muscle differentiation. Occurrence of this neoplasm in the oral cavity is exceedingly rare and its presentation is unusual in children. We present a case report of leiomyosarcoma of the oral cavity in an eight-year old child. Primary oral leiomyosarcoma, being a rare entity in children, this case report emphasizes the prompt recognition of this tumor to institute appropriate multimodality treatment.
Keywords: Leiomyosarcoma, oral cavity, pediatric, soft tissue sarcoma
|How to cite this article:|
Divyambika C V, Sathasivasubramanian S, Krithika C L, Malathi N, Prathiba D. Pediatric oral leiomyosarcoma: Rare case report. J Can Res Ther 2012;8:282-5
|How to cite this URL:|
Divyambika C V, Sathasivasubramanian S, Krithika C L, Malathi N, Prathiba D. Pediatric oral leiomyosarcoma: Rare case report. J Can Res Ther [serial online] 2012 [cited 2014 Sep 21];8:282-5. Available from: http://www.cancerjournal.net/text.asp?2012/8/2/282/98990
| > Introduction|| |
Soft tissue sarcomas are malignant neoplasms of mesenchymal origin which account for about 5-15% of all pediatric malignancies, with rhabdomyosarcoma of the head and neck being the most common sarcoma seen in children. 
Leiomyosarcomas occur commonly in the uterus and gastrointestinal tract of adults and are rarely encountered in children. 
Head and neck leiomyosarcomas are unusual and comprise less than 10% of all leiomyosarcomas. They rarely occur in the oral cavity due to the paucity of smooth muscle content.  Immunohistochemical assay for actin, desmin, HHF 35 and vimentin helps in confirming the diagnosis of leiomyosarcoma.  Early diagnosis and multimodality treatment form the basis of management.
| > Case Report|| |
An eight year old female patient [Figure 1] reported with swelling in the left side of the face of 6 weeks duration associated with dull aching pain. Extra oral examination revealed a swelling in the region of the left cheek, which was firm in consistency. Intra oral examination [Figure 2] revealed a pedunculated growth with surface ulceration in the left buccal mucosa measuring 6x7 cm extending anteriorly from 1 cm behind the left oral commissure and posteriorly up to the retromolar region. Superioinferiorly, the upper and lower buccal sulci were involved. Mandible and overlying skin were clinically normal and the patient did not have trismus.
|Figure 2: Intraoral photograph showing the mass occupying the left side of oral cavity|
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Examination of the neck did not reveal any palpable cervical nodes. Considering the pediatric age group, rapidity of growth and the clinical features, a provisional diagnosis of rhabdomyosarcoma of the left cheek was made.
The patient underwent complete hemogram, renal function and liver function tests, which were normal. Computed tomography (CT) scan of paranasal sinus [Figure 3] showed a heterogenous variably enhancing soft tissue mass involving left masticator and buccal spaces with extension to infratemporal fossa with partial effacement of left parapharyngeal space. Based on CT findings, a diagnosis of soft tissue neoplasm arising from left cheek musculature was made.
Patient underwent biopsy which revealed spindle cells with arranged in interlacing bundles with mild to moderate nuclear pleomorphism [Figure 4] and [Figure 5] suggestive of high grade spindle cell neoplasm. Immunohistochemistry (IHC) was positive for vimentin [Figure 6] Desmin [Figure 7] smooth muscle actin [Figure 8] and negative for myogenin, EMA, S100, CD 34 and HMB 45. Based on IHC, a final diagnosis of leiomyosarcoma was made.
|Figure 3: Coronal slice CT showing heterogenous variably enhancing soft tissue mass involving left masticator and buccal spaces including infratemporal fossa|
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|Figure 4: 100× view of H and E stain showing tumor composed of spindle cells arranged in interlacing bundles with oval vesicular nuclei and indistinct nucleoli|
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|Figure 5: High power view of spindle cell tumor showing many mitotic figures (H and E, 200×)|
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|Figure 6: Masson trichrome stain showing tumor cells staining red indicating muscle differentiation (100×)|
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|Figure 8: Smooth muscle actin immunostain positivity in tumor cells (100×)|
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CT of thorax and ultrasound of abdomen were negative for metastasis. Tc99 MDP bone scintigraphy [Figure 9] showed mild increased tracer concentration in the mandible adjacent to the tumor mass. Subsequently, the patient underwent complete excision of the tumor with clear margins and was advised adjuvant radiation and chemotherapy in view of the size and grade of the tumor. Patient was subsequently referred to a local regional cancer center for adjuvant radiation and chemotherapy; however, she was lost for follow up.
|Figure 9: Tc - 99 MDP bone scintigraphy showing mild increased tracer concentration on the left side of face|
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| > Discussion|| |
Leiomyosarcomas (LMS) account for less than 10% of all head and neck sarcomas usually arising from the jaw (59%).  The rarity of this neoplasm in the oral cavity can be attributed to the paucity of smooth muscle at this site.  Several theories have been proposed to explain the origin of LMS of the oral cavity, the most commonly accepted origin being the vascular wall.  LMS that do develop in the oral cavity are believed to arise from the tunica media or from pluripotent mesenchymal cells. 
Leiomyosarcoma is an extremely uncommon tumor in children.  The patient described in our case report was of 8 years old, which is a relatively uncommon age of presentation of oral leiomyosarcoma. In children, soft tissue sarcomas are classified as either rhabdomyosarcomas (RMS) or nonrhabdomyosarcomas (NRSTS).  Among the NRSTS of childhood, the most common are synovial sarcomas (25 to 50%), followed by fibrosarcomas (15 to 20%), malignant fibrous histiocytomas (10 to 20%), and malignant peripheral nerve sheath tumors (10 to 20%).  In our patient, in view of the age group, denovo origin, short history, rapid growth and clinical features, our preliminary clinical diagnosis was soft tissue sarcoma, most probably rhabdomyosarcoma. However, histopathological and immunohistochemical analyses were suggestive of leiomyosarcoma.
Histopathologically, this neoplasm is characterized by sheets of sweeping, alternating bundles and fascicles of densely packed spindle cells with abundant fibrillar eosinophilic cytoplasm and indistinct cytoplasmic borders, aligned in a palisade pattern.  This malignancy is distinguished from other spindle cell sarcomas with the help of Masson's trichrome staining, Immunohistochemical (IHC) analysis and ultrastructural examination. , IHC based positive reactivity to desmin and muscle specific actin in spindlecell sarcomas and ultrastructural findings of abundant microfilaments, pinocytotic vesicles, and basement membrane formation confirms smooth muscle origin of these tumors , Our patient was positive for vimentin, desmin and smooth muscle actin, thus confirming our diagnosis.
Radical surgical resection is the mainstay of treatment.  Aggressive surgical treatment with Wide local excision and reconstruction with appropriate flap is necessary for radical cure. Despite the rarity of lymph node metastasis, radical neck dissection is recommended for patients with cervical adenopathy.  Adjuvant RT may also have a beneficial effect in terms of reducing local recurrence.  Chemotherapy has been used with the aim of decreasing distal failure and improving survival  as well as for palliating metastatic disease.  In a review of 20 cases of primary oral leiomyosarcoma by Yan et al bone involvement was associated with poorer survival, thereby signifying poor prognosis.  Ethunandan et al reported, tumors with bony involvement, primary presentation with distant metastasis, increasing age and male gender as poor prognostic factors with site of the tumor being a predictor of metastasis.  Despite trimodality treatment, the infiltrative and aggressive nature of this malignancy is reflected in its dismal overall five year disease free survival rate of 23%  and 55%.  In a study conducted by Somerhausen et al with 20 pediatric patients, 85% were considered lowgrade with local recurrence in two patients and the overall prognosis appeared to be better than adults. 
| > Conclusion|| |
Primary oral leiomyosarcoma in pediatric age group is exceedingly rare. Due to its innocuous clinical presentation, the possibility of occurrence of this tumor should also be considered in the differential diagnosis of any oral cavity growth in children. Accurate diagnosis with immunohistochemistry coupled with multimodality treatment is the basis of management of this aggressive sarcoma.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]