A 13-year-old male presented with a rapid enlarging painless diffuse mass located at the right midface and parotid region over the last 6 months. Slight asymmetry of the right commissure, trismus and mandibular asymmetry were evident on initial examination. There were no evidences of regional or distant metastasis. Past medical history included a previous surgical treatment attempt in his native country Honduras, three months prior to his referral (Fig. A). T1 weighted MRI showed a large hyperintense mass measuring 7 x 5 cm, located centrally at the right masticator space with extention into the mandibular ramus, masseter and pterigoyd muscles, parotid gland and parapharyngeal space. Contrast T2 weighted MRI exhibited a high signal with a multinodular and infiltrative pattern (Fig. B).\nAn incisional intraoral biopsy was performed under local anesthesia. The histopathological examination revealed multiple nodules containing tumor cells, immersed in an abundant myxoid stroma separated by fibrous septae. The tumor cells varied in shape from round to elongate, most displaying abundant eosinophilic cytoplasm and round to ovoid excentrically located nuclei, which showed homogeneously distributed chromatin and inconspicuous nucleoli. Other cell types were recognized, mainly spindle, epithelioid and lipoblast-like cells (Fig. ). The mitotic rate was low, averaging two mitotic figures per 10 high-power fields. Periodic acid-Schiff (PAS), with and without prior diastase digestion, demonstrated that the granular cytoplasmic material was glycogen. Immunohistochemical analysis (), showed positivity for vimentin, neuron-specific enolase (NSE), and chromogranin; whereas AE1/AE3, epithelial membrane antigen (EMA), S-100, desmin, muscle-specific actin (HHF35), CD57, Glucose transporter type 1 (Glut-1), synaptophysin, p53, p63, glial fibrillary acidic protein (GFAP), and podoplanin (D2-40) were negative. The Ki-67 labelling index was 42% after evaluation of 1000 cells per five high-power fields (Fig. ). Fluorescent in situ hybridization was not performed; however, the histomorphological and immunohistochemical findings supported a final diagnosis of EMC.\nThere were no evidences of regional or distant metastases, and the patient was treated with en-bloc surgical resection, including ipsilateral hemi-mandibulectomy, total parotidectomy with facial nerve dissection, neck dissection level I to IV and reconstruction with a mandibular plate and major pectoralis flap. Macroscopically, the specimen measured 8 x 6 x 5 cm consisting of an irregularly shaped mass attached to the mandibular ramus, with a multilobular and gelatinous rubbery tissue. Focally, the tumor was present in one surgical margin, immediately anterior to the mandibular condyle. Microscopic evaluation revealed the same histopathological features found in the incisional biopsy. The patient received adjuvant radiotherapy but died after 1 year of follow-up due to complications of locoregional tumor dissemination to the skull base.
A 47-year-old Iranian male patient referred to our outpatient clinic in the Imam Khomeini Hospital, Sari, with a palpable and painless mass in his left shoulder.\nThe patient did not complain about pain or weakness in this location. On examination, the mass was small, mobile, firm, and nontender located in the soft tissue of left shoulder. The skin covering the mass was intact, and there was no ecchymosis and even erythema (). The shoulder range of motion had no functional impairment, and the patient was able to do the routine tasks with no neurovascular disturbance. Medically speaking, important clinical signs and symptoms such as fever, weight loss, and respiratory symptoms were not detected.\nThere was no visible fluctuation in this field, and it was estimated 0.5-1 cm in length and width. Tumor consistency was not similar to bone, and it seemed to be a soft tissue mass. The patient denied any history of trauma and also no significant family history was identified. Interestingly, the patient was operated by general surgeon 6 times because of relapses in a way the last one was 1.5 years ago. At the first time, the patient was referred to the outpatient clinic because of gradual mass enlargement. The patient was operated by wrong method as transverse approach in the lateral border of the shoulder ().\nIn the recent recurrence, chest X-ray showed no obvious lung or bone involvement ( and ). Magnetic resonance imaging (MRI) illustrated a small extraskeletal nodular lesion with ring enhancement and no bone involvement at subcutaneous fat on lateral aspect of shoulder measuring about 13 mm which could be due to a recurrence of the previous tumor ( and ). Unfortunately, no previous documentation such as MRI was found. Thus, this caused difficulty for interpretation of the course of the main disease.\nFirst, we decided to operate the tumor as an incisional biopsy because we were not sure about the nature of the lesion. An important note in this approach was limited access to the lesion because of an incorrect previous approach. Pathologic specimen confirmed the diagnosis of chondrosarcoma. Then, he underwent a wide resection of the lesion in the beach-chair position. In surgery, the five dense fibrotic and firm masses measuring from 0.5 to 2 cm and the middle part of deltoid muscle (because of involvement) were excised and sent to pathology ward. Microscopic examination showed infiltrative hypercellular islands of pleomorphic chondrocytes composed of enlarged cells with irregular hyperchromatic nuclei and inconspicuous cytoplasm which was compatible with the diagnosis of chondrosarcoma with free surgical margins ( and ). We should say that the diagnosis was based on the characteristic clinical, radiologic, and pathological criteria; moreover, it was confirmed by immunohistochemistry. Hence, after consulting with the oncologist, radiation therapy was done. We have followed the patient for 6 months after operation, and until now, no recurrence is recognized.