Abstract
Rhabdomyosarcoma is a malignant skeletal muscle neoplasm which frequently involves head and neck region. It is the second most common soft tissue sarcoma encountered in children. RMS is an aggressive neoplasm with extensive local invasions and early hemorrhagic and lymphatic dissemination. Here, we report a case of oral RMS in a 7-year-old girl from Bangladesh. Histologically, the tumor consisted of a classic embrayonal rabdosarcomatous area was observed in the biopsy specimen. Furthermore, we discuss about the clinical, radiological, immunohistochemical findings, and management of the aforementioned RMS case.
Highlights
- •
Rhabdomyosarcoma (RMS) is malignant tumor of interest for children due to its diagnostic difficulty, treatment dilemma and fatal outcome.
- •
As conventional histopathology fails, immunohistochemistry becomes the main tool for proper diagnosis.
- •
Neo-adjuvant chemotherapy, surgery and adjuvant chemo-radiation can increase the survival of RMS.
1
Background
Rhabdomyosarcomas (RMS) are malignant soft tissue tumors of primitive mesenchymal cells that undergo partial rhabdomyoblast differentiation and is the second most common sarcoma in children after osteosarcoma. RMS represents approximately 4–8% of all cases of malignant disease in children younger than 15 [ ]. These tumors are bimodal in distribution, and often present in patients younger than 5 years of age and ages between 10 and 18 years [ ]. The most common sites of involvement of RMSs are oral & maxillofacial area, genitourinary tract, retroperitoneum, and extremities. However, RMS has a string predilection towards head and neck area with the posterior maxilla/orbit is the most commonly affected location followed by the nasal cavity, mouth, sinuses, cheek and neck [ ].
Clinically, the tumor presents as a rapidly growing mass, readily invades surrounding bone, which is occasionally associated with pain, trismus, paresthesia, facial palsy, and nasal discharge [ ]. RMSs are not radiologically distinctive but primarily show the anticipated soft tissue mass and bony destruction. Histologically, RMS is one of the “small round cell” tumors, presenting with sheets of small cells with large prominent nuclei. There are three basic histologic types: (a) embryonal, (b) alveolar & (c) pleomorphic. The embryonal type having the best prognosis, most commonly observed in children under 10 years of age, and accounts 60% of all RMS cases [ ]. The alveolar form peaks in childhood and adolescence.
The management of RMS includes multimodal therapy, where chemotherapy plays an important role and often associated with radiotherapy depending on the severity of the disease. Recently there has been a trend requiring the involvement of surgery in head and neck disease as a precise therapy. Primary surgical resection with complete excision is recommended for localized disease. Surgery is also indicated when there is resectable residual local and regional disease. The intergroup Rhabdomyosarcoma study (IRS) has established a staging system based on local excision rather than radical surgery and takes into account tumor size as it relates to the degree of excision. These are, Group I, refers to localized disease and microscopic margins free of tumor, and Group II, indicates grossly negative but microscopically positive margins. Group III indicates grossly visible disease left at the time of surgery, and Group IV shows distant metastasis irrespective of the tumor resection margins. Typically, chemotherapy continues for a year or two depending on the suspicion of presence of residual disease [ , ]. While 5-year survival is 83% for group I tumors, the survival outcome gradually decreases in advanced groups as the poorest survival outcome observed in group IV with only 20% [ , ].
Here, we report a case of a 7 year-old Bangladeshi girl with oral RMS on right side of the lower jaw.
2
Case report
A 7 year-old Bangladeshi girl with pain and swelling on the right side of the face for 15 days duration was referred to the Department of Oral & Maxillofacial Surgery, Dhaka Dental College Hospital, Dhaka, Bangladesh. The patient reported a history of pain and swelling two and half years ago on the same side of face, and was diagnosed with PNET (Primitive Neuro-Ectodermal Tumor) from FNAC on May 13, 2017. She had 6 cycles of chemotherapy followed by right parotidectomy. Further, 8 cycles of chemotherapy was administered and the lesion was reduced, and the right sided face appeared normal. Eight months later, the lesion reappeared and 2 cycles chemotherapy with Vincrystine (intravenous injection 0.9 mg on day 1), Irinotecan (intravenous injection 30 mg on day 1 to day 5) and dexamethasone were was given. MRI was conducted and revealed a heterogeneous soft tissue mass over the right lower jaw, parotid region including infratemporal fossa, right lateral pharyngeal wall, surrounding mucosa and soft tissue. Later, she was referred to Dhaka Dental College Hospital, Bangladesh with residual disease.
Extra-oral examinations, revealed a diffuse swelling on the right side of middle and lower face measuring about 10cm <SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='×’>××
×
7cm in diameter, extending supero-inferiorly from eye brow line to lower border of the face, antero-posteriorly right angle of the mouth up to post auricular region. Paresthesia of right lower lip and chin was detected. Skin color was normal. There was no discharging sinus & no visible pulsation. However, a 4 cm scar mark was visible on the right side of the neck. The swelling was mild tender and firm in consistency ( Fig. 1 a).
Intra-oral examination, revealed a diffuse swelling of about 6 cm × 5 cm in diametre on the right posterior buccal mucosa, extending from upper vestibule to lower vestibule and with from lower right 2nd deciduous molar to tonsillar area. The swelling was tender and firm in consistency. The overlying mucosa was normal in color without any obvious ulceration ( Fig. 1 b). The patient was in mixed dentition, with mobility of deciduous molar and permanent first molar teeth. Tongue was normal in appearance and function. The reminder of the intraoral cavity was unremarkable.
In regional lymph node examination, there was a palpable, mobile, non-tender, enlarged sub-mental lymph node on the right side of the face, which was about 1cm <SPAN role=presentation tabIndex=0 id=MathJax-Element-2-Frame class=MathJax style="POSITION: relative" data-mathml='×’>××
×
1.5cm in diameter. Another palpable, mobile, non-tender, enlarged sub-mandibular lymph node was noticed on the left side with 1cm <SPAN role=presentation tabIndex=0 id=MathJax-Element-3-Frame class=MathJax style="POSITION: relative" data-mathml='×’>××
×
0.5cm in diameter.
Orthopantomogram (OPG) revealed ill-defined radiolucency on the right side of the body of the mandible, extending from right canine through the ramus to the condyle of the right mandible where lower border was intact. Resorption of roots of right lower permanent first molar, upward displacement of second molar, normal position of premolars and deciduous molars were evident ( Fig. 2 ).
