Oropharyngeal Rhabdomyosarcoma with cranial nerve paralysis in a limited resource setting: a case report and review of literature

Rhabdomyosarcoma (RMS), a tumor of skeletal muscle origin, is the most common soft tissue sarcoma encountered in childhood and adolescence; it is primarily found in the head and neck region, it is relatively uncommon tumors of the oral cavity. Clinical signs depend on the exact location of the lesion in the oral cavity and its development. Authors reported the case of a 14-year-old patient who presented an oropharyngeal mass causing voice dysfunction, after two surgical operation the patient experimented two 2 recurrences of the lesion. The histopathological examination objectifies an oropharyngeal rhabdomyosarcoma. Immediate postoperative outcome was uneventful with improvement in the voice dysfunction and dysphagia one month after surgery. Complementary treatment (chemotherapy and radiotherapy) was not available and accessible to the patient. Twenty months (20) after surgery, the examination found a recurrence of the tumor with pulmonary metastases and neurological complications. Oropharyngeal rhabdomyosarcomas are rare. Their interest lies in the fact that they often affect children and adolescents. The prognosis remains unfavorable in our context, even for cases accessible to surgery since complementary treatment with chemotherapy and / or radiotherapy does not exist. The prognosis depends on tumor size, location, staging, age of patients and especially the quality of the management.


Introduction
Rhabdomyosarcoma (RMS) constitutes a heterogeneous and aggressive malignant soft tissue neoplasm arises from undifferentiated mesodermal tissue [1][2][3][4]. RMS is primarily in striated muscle but can originate in the soft tissue that does not normally contain striated muscle [1,3,5]. RMS is the most common soft tissue sarcoma among children and adolescents [1,4,6]. This tumor accounts for 5% to 10% of all malignancies in childhood tumors [1,[5][6][7]. All parts of the body can be affected by RMS, but the most affected sites are the head and neck region in 40%, the genitourinary tract in 23%, the extremities in 20% and the other parts in 22% [3, 6,8]. RMS located at the level of the head and neck can occur in the paramenigeal areas such as the orbit, ear, nasal cavity, sinus, nasopharynx and infratemporal fossa. Non-meningeal locations include the scalp, parotid gland, oral cavity, pharynx, thyroid and parathyroid [8][9][10]. The oropharyngeal cavity is even more rarely reported in the literature [1,5,9,10]. The treatment of RMS must be multidisciplinary and depends on the site. Complete initial resection of the tumor with healthy margins is ideal [5][6][7][8]. However, chemotherapy (neo-adjuvant and/or adjuvant) and radiotherapy are used in addition to surgery or as therapeutic alternatives for inoperable cases [2,10,11]. In our context, the delayed diagnosis, and the lack of the technical platform are aggravating factors of this cancer which prognosis is already bad. Here we report the management of oropharyngeal rhabdomyosarcoma in a 14-year-old male patient at Maradi regional hospital (CHR). A 14-year-old patient, from the rural area, with precarious socioeconomic status, consulted at the Ear Nose Throat (ENT) department of Maradi CHR for an oropharyngeal mass evolving for several months.

Patient and observation
The last three months, the mass has increased in volume significantly.
The patient had functional signs such as dysphonia, dysphagia and pain. At admission, the patient had a good general status. The conjunctiva and mucous membranes were normal-colored. At the opening of the mouth, the examination of the oropharyngeal cavity, noted an indolent mass, nodular, bloody and located on the right side of the oral cavity. The major axis of the mass measured approximately 5 to 6 cm ( Figure 1). The biological investigations were without anomalies. Standard chests X-ray, abdominal and cervical ultrasound were normal. Computed tomography was not available in our hospital and the parents of the patients did not have the financial resources to evacuate their child to the capital Niamey which is about 600 miles away. The diagnosis of oropharyngeal tumor was made and the surgical indication of a biopsy excision was made. The child underwent general anesthesia with orotracheal intubation. The installation was done in order to obtain the extension of the neck and the head. After opening the mouth, the lesion was exposed, gross macroscopic resection of the tumor was performed. The specimen was sent for histopathological examination that revealed a malignant tumor proliferation with diffuse disposition, the cells had an oval nucleus and eosinophilic cytoplasm, as rhabdomyoblastic. The tumor cells have a perivascular disposition and there is a lot of mitosis. In conclusion, the diagnosis of an embryonal rhabdomyosarcoma botryoid variant was retained.
Immediate postoperative outcome was uneventful with improvement in the voice dysfunction and dysphagia one month after surgery. The patient was referred to Niamey at the oncology department for adjuvant chemotherapy, but the parents reaffirm that they could not afford to bring their son to Niamey. After a return visit at 3 and 6 months at the CHR of Maradi, the patient was lost sight of. He  [5,7,9]. The reported case is located in oropharyngeal region, which is not very common as assumed many authors [5,[7][8][9][10]. The most common site is the head and neck (parameningeal and orbit), followed by genitourinary tract. Less commonly involved sites of head and neck regions are the nasal cavity and nasopharynx, ears, paranasal sinuses, soft tissue of the face and neck [11,12].
The histologic classification of rhabdomyosarcoma remains very controversial, as several distinct morphological variants have been reported [3,4]. Horn and Enterline [13] were the first to propose the subdivision of RMS into 4 types botryoid, embryonal, alveolar and pleomorphic. Formerly, pathologic classification divided RMS into two main types embryonal and alveolar [1,6]. The embryonal type presents the subtypes including spindle cell and botryoid [1,6,11,12]. However, the current World Health Organization (WHO) classification [14], is closer to that proposed by Horn and Enterline [13]; it groups the RMS into four histologic groups: rhabdomyosarcoma. It should be noted that pleomorphic RMS is most often found in adults, but rare in children [14]. The histolopathological type of our patient was embryonal rabdomyosarcoma botryoid variant.
The diagnosis of RMS should be based not only on the histopathological aspect, but also on the immunohistochemical and molecular profiles of these tumors. These exams are not available in many developing countries. Molecular diagnosis not only confirms RMS but also monitors residual disease. It allows especially targeted treatment [1]. The treatment of RMS involves a multimodal approach.
Treatment should be undertaken in oncology centers with multidisciplinary teams [7,12,15]. increase the risk of recurrence [8]. The overall survival of patients with RMS has improved considerably over the past two decades because of diagnostic and therapeutic progress [6][7][8]. The five-year survival rate of SMR has improved, from less than 10% before the 1960s to 65% today [10]. This survival at 5 can reach 85% for low-grade localized RMS [6]. This rate decreases considerably with age, height and advanced stages at the time of diagnosis of RMS [6], but remember that RMS is an aggressive tumor with rapid growth in children [11]. Nearly 25% of cases of RMS are metastatic at presentation [3, [6][7][8]. RMS are associated with high rates of recurrence metastases through the blood and/or lymphatic routes [10]. The most common site of metastasis was bone, followed by a lung and lymphadenopathy [7].

Competing interests
The authors declare no competing interests.

Authors' contributions
Askia Alfazaz: contribute in the redaction of the case observation.
Ibrahim Assoumane: contribute in the redaction of the manuscript.
Ousseini Adakal: contribute in the correction of the manuscript.