|Year : 2003 | Volume
| Issue : 2 | Page : 49-51
Rhabdomyosarcoma of the oral cavity mimicking gingival epulis: Report of two cases
S Pande, SM Ganvir, VK Hazarey
Department of Oral and Maxillo Facial Pathology and Microbiology, GDCH, Nagpur, India
V K Hazarey
Department of OMFPM, GDCH, Nagpur 63
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Rhabdomyosarcoma is an uncommon malignant tumour of striated muscle. Two cases of rhabdomyosarcoma involving the gingiva are discussed here with the initial clinical appearance as a pedunculated gingival growth or epulis. One of the cases was diagnosed by FNAC of the lesion. The article thus lays emphasis on the cytodiagnosis of oral lesions with a brief review of rhabdomyosarcomas of head and neck.
Keywords: Rhabdomyosarcoma, cytodiagnosis, epulis
|How to cite this article:|
Pande S, Ganvir S M, Hazarey V K. Rhabdomyosarcoma of the oral cavity mimicking gingival epulis: Report of two cases. J Oral Maxillofac Pathol 2003;7:49-51
|How to cite this URL:|
Pande S, Ganvir S M, Hazarey V K. Rhabdomyosarcoma of the oral cavity mimicking gingival epulis: Report of two cases. J Oral Maxillofac Pathol [serial online] 2003 [cited 2020 Sep 30];7:49-51. Available from: http://www.jomfp.in/text.asp?2003/7/2/49/40938
| Introduction|| |
Tumours of skeletal muscle, particularly rhabdomyosarcoma, have always been a source of fascination and frustration for pathologists. Their diverse pattern ranging from seemingly innocuous to the bizarre and pleomorphic types has trapped the unwary into either positive or negative errors of diagnosis. Frequently masquerading as an inflammatory polyp, oral, aural or nasal, the neoplasm if unchecked, manifests a high lethality and until recently was resistant to even the most aggressive surgical management. In recent years, the dismal prognosis for the patients with rhabdomyosarcoma has changed remarkably. This has been accomplished as a result of a better understanding of the natural history of the disease, careful clinical staging of the malignancy, an awareness of the histological features, new techniques for accurately defining the disease extent and therapeutic and supportive therapy.
From a histomorphological viewpoint, rhabdomyosarcoma is the neoplastic analogue of skeletal muscle embryogenesis. Two different case reports of rhabdomyosarcoma are discussed in this paper with a brief review.
| Case 1|| |
A 22 year-old-male reported to our institution in 1977 with the chief complaint of a rapidly appearing growth in the upper left premolar molar region. Patient gave history of exfoliation of his upper left premolars and first molar and the growth has been present since then in the extraction site. Intra orally the upper first molar and both premolars were absent and a growth was seen extending from the gingival area onto the palate. Extraorally no abnormality was detected. Biopsy from the lesion revealed the diagnosis of a malignant mesenchymal tumour [Figure 1], which was myoglobin and vimentin positive. The diagnosis of rhabdomyosarcoma was given.
| Case 2|| |
A 65-year-old female reported to our institution in 2003 with the chief complaint of swelling in the left side of the oral cavity present since one month. Following extraction of her lower left lateral incisor and first premolar a month back with a private practitioner, she reports of constant bleeding from the extraction site, followed by a sudden swelling in the lower left vestibule.
Intra orally, a single, large, exophytic, lobulated and pedunculated growth was seen in the lower left buccal vestibule extending from the lower lateral incisor to the first molar region. The growth was measuring about 6x4cm 2 in size with a smooth surface and was bleeding on the slightest provocation. The entire mass was covered with slough and extended into the buccal vestibule as well as onto the lingual aspect on the floor of the mouth [Figure 2].
Considering its rapidity of growth and clinical appearance with extreme vascularity, a differential diagnosis of a sarcomatous lesion, or a metastatic lesion was considered. Skeletal scintigraphy of the whole body revealed no other lesion elsewhere. Left side of the mandible gave evidence of a hot nodule surrounded by a cold nodule in the center, thereby confirming malignancy.
FNAC from the lesion was taken and the smears were stained with PAP and hematoxylin and eosin. Cytological smears revealed high cellularity of small groups and predominantly single cells of the spindle cell type, tadpole type, and plump round cells. Cells had large hyperchromatic nuclei with prominent nucleoli and abundant well-defined eosinophilic cytoplasm. Tumor giant cells as well as large number of mitotic figures and many binucleated cells were seen [Figure 3],[Figure 4]. Features were suggestive of a malignant mesenchymal tumor. Considering the age of the patient and the cytological details, a diagnosis of pleomorphic rhabdomyosarcoma was given.
Patient was operated under general anesthesia and segmental mandibular resection was done. Histopathological section showed the presence of loosely arranged, haphazardly oriented, large round or pleomorphic cells with hyperchromatic nuclei and deeply eosinophilic cytoplasm. Presence of racquet shaped and tadpole shaped cells depicting cellular pleomorphism without any evidence of cross striations were seen. Thus diagnosis of pleomorphic rhabdomyosarcoma was confirmed by histopathology [Figure 5],[Figure 6].
| Discussion|| |
The first detailed description of rhabdomyosarcoma was given by Stout  in his report of 121 cases in 1946. The neoplasm described in his paper is one of the several variants of rhabdomyosarcoma, the pleomorphic or adult type. Horn and Enterline  in 1958 classified the other subtypes as: embryonal, alveolar, and botryoid. Recently spindle cell rhabdomyosarcoma has been added as a subtype of the embryonal form.
Pleomorphic or classical rhabdomyosarcoma, accounts for less than 5 % of all cases. It may affect patients of any age group, but has its peak incidence in patients older than 40 years. It is primarily a tumor of the large extremities. Diagnosis is difficult not only because of the consistent absence of the typical rhabdomyoblast with crossstriations but also because of the close resemblance of this tumor to malignant fibrous histiocytoma and other pleomorphic sarcomas  .
Embryonal rhabdomyosarcoma was first described in 1950. It closely resembles developing muscle in the 7 to 10 week old foetus. It is characterized by round to spindle cells of small to moderate size, a central ovoid to round nucleus and occasional cross striations. It is most commonly seen in children and is the frequent type involving the head and neck region  .
Alveolar rhabdomyosarcoma, which derives its name from the alveolar arrangement of its cells, is a rare variant of rhabdomyosarcoma characterized by alveolar spaces that are either round or elongated and often showing 'out pouching'. Many tumor giant cells are seen with "wreath" like appearance.
Botryoid rhabdomyosarcoma is usually considered as a variant of embryonal rhabdomyosarcoma. One of the distinctive histological features of this type is the presence of more or less compact layer of parallel rows of cells immediately beneath the mucous membrane ('cambium layer') below which the neoplasm assumes a more sparse cellular arrangement.
Ditto and Batsakis  were the first to consider the biological activity of rhabdomyosarcoma of the head and neck as distinctive lesions from the other rhabdomyosarcomas. In their extensive study of 170 cases of rhabdomyosarcomas, they found the head and neck lesions to comprise 17 % of the total, with 77 % of them occurring in patients 12 years or younger in age at the time of diagnosis. Further, head and neck rhabdomyosarcomas possessed a significantly rapid rate of growth with high metastasis rate. Histologically, the most common variety of rhabdomyosarcoma is the embryonal or botryoid form depending on whether or not the neoplasm is associated with the mucous membrane surface of the oral cavity. Adult pleomorphic type is less common with a predilection for the oral tongue.
Till now, only one of case pleomorphic rhabdomyosarcoma of the gingiva has been reported in the literature. The present cases would probably rank as second and third, with similar clinical presentation.
Histogenesis of rhabdomyosarcoma is controversial, as shown by an example reported by Tsnaguchi et al  which had apparently arisen from the stroma of a long standing ameloblastoma in a 65-year-old male patient. Many rhabdomyosarcoma sdo not arise in striated muscle. Enzinger and Weiss proposed two histogenic possibilities for rhabdomyosarcomas  , one from the primitive and undifferentiated mesenchymal cells and the other from the embryonal muscle tissue displaced during early stages of development.
Genetic changes like t  , familial occurrence or occasional trauma may serve as a trigger mechanism to induce such growth.
Special stains such as Masson's trichome, PTAH and, iron hematoxylin compliment the morphological findings and facilitate the scanning of multiple sections for the presence of differentiated cells among the poorly differentiated components and hence were used in the past to highlight the skeletal muscle origin. Cells of rhabdomyosarcoma contain abundant PAS positive intra cellular glycogen that can be useful in the differential diagnosis of small cell tumours. Immunohistochemical stains  such as myoglobin, muscle specific actin HHF35, vimentin, desmin and myosin can be used as markers of rhabdomyosarcomas.
Biological behaviour & management ,,
The first line of treatment is radical excision and this is usually supplemented by radiotherapy. It is believed that adjunct combination chemotherapy may greatly improve the prognosis. Inadequately treated tumours grow in an infiltrative manner and recur in a high percentage of cases. Bone does not constitute an effective barrier to the growth of the tumour and bone invasion is a frequent finding in head and neck rhabdomyosarcomas. Metastasis develops during the course of the disease or is present in about 20% of cases at the time of diagnosis. Major sites of metastasis are the lungs, lymph nodes and bone marrow followed by heart, brain, meninges, pancreas, liver and kidney.
| Summary|| |
The case reports presented were unique in respect to , the clinical appearance and location. As the second case in our study was diagnosed by cytology, the importance of cytodiagnosis cannot be over emphasized as it gives a better clue to the clinicians before hand. A thorough understanding of the aggressive clinical behaviour and the diverse histopathological appearance will enable us to treat the sarcomas with dubious biological behavior more effectively, at the earliest possible.
| References|| |
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|3.||Enzinger F M , Weiss SW (1995) : Rhabdomyosarcoma. In soft tissue tumors, (3rd ed.), CV Mosby, St Louis, pages 539-577. |
|4.||Ditto WR, Batsakis JG (1962): Rhabdomyosarcoma of the head and neck: an appraisal of the biologic behaviour in 170 cases, Arch Surg, 84: 112-118. |
|5.||Tnanaguchi K, Okamura K, Matsura H, Ogou K, Honda T and Kitamura (1995): Rhabdomyosarcoma arising in a case of long standing ameloblastoma, Oral Surg Oral Med Oral Pathol Oral Radiology Endol, 80: 202-206. |
|6.||Donaldson SS, Castro JR, Wilbur JR & Jesse RH Jr (1973): Rhabdomyosarcoma of head and neck in children. Combination treatment and Surgery, irradiation and chemotherapy, Cancer, 31: 26. |
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6]