|Ahead of print publication
Radiation-induced leiomyosarcoma of oral cavity: Two cases with a review of literature
Nishant Sagar1, Meeta Singh1, Neelakshi Goyal1, Nita Khurana1, Kishore Singh2, Ravi Meher3
1 Department of Pathology, Maulana Azad Medical College, New Delhi, India
2 Department of Radiation Medicine, Maulana Azad Medical College, New Delhi, India
3 Department of Otolaryngology, Maulana Azad Medical College, New Delhi, India
|Date of Submission||17-Oct-2018|
|Date of Decision||17-Apr-2019|
|Date of Acceptance||16-May-2019|
|Date of Web Publication||29-Jan-2020|
Department of Pathology, Maulana Azad Medical College, New Delhi
Source of Support: None, Conflict of Interest: None
Radiation-induced sarcoma is a rare entity, with leiomyosarcoma (LMS) in the oral cavity post radiation being extremely rare. We report two such cases who presented with swelling in the oral cavity with a history of moderately differentiated squamous cell carcinoma. Both cases prior to the diagnosis of LMS had been managed with surgery and radiation therapy and later developed swelling in the oral cavity. The management of LMS is uncertain; hence, this article aims to spread awareness about this rare diagnosis and to know the importance of differentiation from other more common lesions including recurrence.
Keywords: Oral leiomyosarcoma, radiation-induced sarcoma, squamous cell carcinoma
|How to cite this URL:|
Sagar N, Singh M, Goyal N, Khurana N, Singh K, Meher R. Radiation-induced leiomyosarcoma of oral cavity: Two cases with a review of literature. J Can Res Ther [Epub ahead of print] [cited 2020 Oct 31]. Available from: https://www.cancerjournal.net/preprintarticle.asp?id=277279
| > Introduction|| |
Radiation-induced sarcoma (RIS) is a well-known albeit rare complication of radiotherapy. The reported incidence of RIS is roughly between 0.03% and 0.3%. Commonly encountered RISs include osteosarcoma, malignant fibrous histiocytoma, osteosarcoma, chondrosarcoma, and fibrosarcoma. Radiation-induced leiomyosarcoma (LMS) is extremely rare in the head-and-neck region, with only seven cases reported in literature at extraorbital location [Table 1].,,,,,, In this article, two cases of radiation-induced LMS in the head-and-neck region are described along with a review of literature.
|Table 1: Reported cases of radiation-induced head-and-neck leiomyosarcoma|
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| > Case Reports|| |
A 58-year-old female presented with a previously diagnosed and treated case of moderately differentiated squamous cell carcinoma stage T4aN2bM0 in the left buccoalveolar region. The patient underwent wide local excision of the tumor with negative surgical margin and modified radical neck dissection followed by adjuvant radiotherapy. She received 22 fractions of radiotherapy, at a total dosage of 66 Gy for a period of 2 months following which she was declared disease free. Two years later, she developed swelling in the hard palate measuring 4 cm × 3 cm. The mass was excised and sent for histopathological examination. Grossly, the specimen comprised an irregular mass measuring 4 cm × 3.5 cm × 2.5 cm. Microscopic examination revealed spindle cells with moderate pleomorphism, brisk mitosis, and mitotic count (12/10 hpf), with large areas of necrosis [Figure 1]a and [Figure 1]b. On immunohistochemistry (IHC), these tumor cells were positive for vimentin [Figure 1]c, smooth muscle actin-positive (SMA) [Figure 1]d, and desmin, while negative for creatine kinase (CK), epithelial membrane antigen (EMA), S-100, ALK, and CD68, thus diagnosed as radiation-induced LMS.
|Figure 1: (a) Tumor showing fascicles of spindled cells with large areas of necrosis (H and E, ×100). (b) Bizarre tumor giant cells and pleomorphism (H and E, ×600). (c) Cells showing smooth muscle actin positivity (immunohistochemistry, diaminobenzidine chromogen, ×600). (d) Cells showing desmin positivity (immunohistochemistry, diaminobenzidine chromogen, ×600)|
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A 60-year-old diabetic female presented with a previous history of moderately differentiated squamous cell carcinoma in the left buccoalveolar region. She underwent wide local excision of the tumor with negative surgical margin and modified radical neck dissection and given 20 fractions of adjuvant radiation for 3 months with a total dosage of 60 Gy following which she was declared disease free. After 3 years, she developed a swelling near the site of primary malignancy measuring 5 cm × 4 cm. Contrast-enhanced computed tomography (CECT) showed soft-tissue enhancement in the left buccal region reaching up to the skin [Figure 2]a. The mass was excised and sent to our department. Grossly, the mass was globular measuring 4 cm × 3 cm × 2.5 cm. Cut section was solid and gray white. Microscopic examination revealed plump spindle cells with moderate pleomorphism and mitotic count of 10/10 hpf with evidence of vascular invasion [Figure 2]b. No necrosis was identified. On IHC, these tumor cells were positive for vimentin, SMA [Figure 2]c, and desmin [Figure 2]d, while negative for CK, EMA, S-100, and CD68, suggestive of radiation-induced LMS.
|Figure 2:(a) Contrast-enhanced computed tomography showing soft tissue enhancement in the left buccal region. (b) Bizarre tumor giant cells, pleomorphism brisk mitosis (H and E, ×600). (c) Cells showing vimentin positivity (immunohistochemistry, diaminobenzidine chromogen, ×600). (d) Cells showing smooth muscle actin positivity (immunohistochemistry, diaminobenzidine chromogen, ×600)|
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| > Discussion|| |
Radiotherapy is a double-edged sword, with RIS as one of its complications. RIS has been reported in cases of carcinoma breast, Hodgkin's disease, carcinoma cervix, and bone and soft-tissue malignancies., The head-and-neck region is an extremely rare site, with an incidence rate of 1%. RIS LMS is extremely rare even more so in the head-and-neck region.,,,,,, To render a diagnosis of RIS, revised criteria were proposed by Murray et al. which included:
- History of irradiation with the sarcoma arising in the area included in the radiation field and the 5% iso dose line
- No evidence that the sarcoma was present before the radiation therapy
- Sarcomas must be proven histologically and be of different pathology compared with the primary tumor.
The latency period for the development of RIS is typically 5–20 years. However, consensus does not prevail to agree the duration of latency after radiation exposure. The sarcoma team at the Memorial Sloan Kettering Cancer Center suggests that a latency of 6 months is sufficient to affirm the diagnosis of RIS. The shorter latency period can be attributed to advancement in radiotherapy techniques.
The exact pathogenesis of the development of RIS remains unknown. Studies show that tumor suppressor gene including p53 mutation plays an important in RIS as indicated by the overexpression of p53 on IHC in these cases. The role of Rb gene has also been studied.
LMSs are rare in the oral cavity, be it primary, metastatic, or radiation induced, which can be attributed to lack of smooth muscle in the oral cavity. Studies suggest that LMS arises from blood vessel wall, circumvallate papillae, or pleuripotent stem cells.
Due to paucity of cases reported in literature, the accurate management cannot be ascertained. The prognosis remains poor, with the only best treatment of choice being surgical excision with negative tumor margins. However, due to difficulty in complete excision of head-and-neck lesions, chances of recurrence and metastasis are high. The role of chemotherapy is uncertain. Literature suggests that systemic chemotherapy may improve the outcome, but should be administered only when the benefit outweighs the risk of toxicity.
| > Conclusion|| |
RIS LMS in the oral cavity is a rare entity. As a result, its pathogenesis remains poorly understood. Management protocols are not standardized currently and require more studies.
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.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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