# Unusual Presentation of Juvenile Rhabdomyosarcoma in the Temporomandibular Area: A Case Report
## 2 Case Report  
A 12-year-old male was referred to the Unit of Orthodontics and Dental Sleep Medicine in the Department of Biomedical and Neuromotor Sciences of the University of Bologna to be evaluated by an orofacial pain specialist. The patient reported intermittent very intense stabs of pain occurring every 5 min, with a continuous dull pain around the ear, in the temple and in the jaw on the right side. A limitation in mouth opening was also reported. The patient associated the onset of the symptoms to a hit on the face received during water polo training 4 months earlier. The pain worsened over time and did not respond to drug therapies. The clinical examination was performed following the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) [13]. The non-assisted mouth opening presented a severe limitation (24 mm) and a mandibular deviation on the right side. The assisted and passive mouth opening were 35 and 40 mm, respectively, and exacerbated the pain in the right temporomandibular area and in the temple. The palpation of the right mansester and temporalis muscles caused severe pain to the patient, while no muscle pain was registered on the left side. Paresthesia in the right temporomandibular joint (TMJ) area and hyperalgesia in the right side of the mandible were also registered. No acute dental conditions, periodontal inflammations, nor intra- and extra-oral swelling were detected. The patient had been previously evaluated by other colleagues: a pediatrician prescribed analgesics and non-steroidal anti-inflammatory drugs (paracetamol and ibuprofen) for pain control, obtaining scarce success. An ENT specialist prescribed steroidal anti-inflammatory drugs that were also not effective in pain reduction and requested for a computerized tomography (CT) that did not show significant problems affecting the facial bones and the TMJ. Further investigating the history, a discomfort related to the jaw movement previous to the facial trauma was also reported by the patient: it started about one year earlier as an impairment and worsened over time. The clinical aspects and the evaluation of the anamnesis suggested a request for a Nuclear Magnetic Resonance (NMR) of the skull and of the TMJs. The NMR revealed a solid expansive lesion without hypervascularization in the right pterygoid area with a diameter of 61 \(\times\) 40 mm in the axial plane and a craniocaudal extent of 59 mm. The upper portion of the lesion eroded the skull base invading the intracranial area. The lateral portion reached the mandibular ramus extending from the angle to the condyle, that appeared reduced to in size due to the erosion of its medial portion by the tumor. The retro-lateral lymph nodes appeared enlarged (Figure 1).  
An incisional biopsy was performed and the histological examination revealed the presence of epithelloid and spindle cells with pleomorphic, hyperchromatic nuclei with eosinophilic cytoplasm, arranged in nests and chains, with perivascular thickening (Figure 2). Immunohistochemistry was performed for Ki-67, muscle actin, S100, CD34, CD45, CD30, desmin, CD99 and myogenin. Desmin and Ki-67 showed high positivity. CD99 and myogenin revealed patchy positivity, and broad-spectrum cytokeratin was focally positive (Figure 3). The fluorescent in situ hybridization (FISH) technique was used to evaluate the rearrangement of FOX01: the translocation was negative. Based on these characteristics, the tumor was classified as ERMS. The young patient underwent chemotherapy which had a poor prognosis due to the large size of the tumor mass.  
Figure 1: NMR: coronal (**a**) and transverse (**b**) sections of the RMS showing the extent of the tumor.  
Figure 2: Hematoxylin–eosin stain of the tumor mass in the temporomandibular area: (**a**) high magnification microscope view (400\(\times\)). Cell proliferation organized in nests and chains. Presence of eosinophils and clear cytoplasm; (**b**) medium magnification microscope view (100\(\times\)). Epithelial-like and spindle cells with pleomorphic and hyperchromatic malignant nuclei.