CASE PRESENTATION
A 7-year-old girl presented at her local maxillofacial department with pain on the left side of the mandible. Two months before presentation these complaints began as intermittent pain. The left jaw began to swell and ache intensively. The diagnosis of inflammation was most probable given the young age, pain and the localized swelling.11 Before any imaging, the local maxillofacial surgeon tried to treat a possible abscess by incision combined with intravenous (IV) amoxicillin clavulanic acid. Only significant edema of the soft tissue without pus drainage was recorded. Superficial necrosis was noticed due to friction of the upper molars in the left cheek (Figure 1A). The patient had no medical history. A referral to the university hospital took place.
After panoramic radiograph (Figure 2) further imaging modalities were initiated based on osteolytic lesions found in the lower left quadrant. Absence of the thin circumferential cortical layer around the second molar in the lower jaw on the left side was recorded.12 Through ultrasound imaging an inhomogeneous, relatively well-defined soft tissue mass was shown above the submandibular salivary gland with invasion in the mandible. A computed tomography (CT) (Figure 3C) was performed which showed a mass in the left masseter muscle region, fixed to the ascending mandibular ramus with osteolysis of the bony tissue. These findings were confirmed using magnetic resonance imaging (MRI)(Figure 3B). For staging a positron emission tomography – computed tomography (PET-CT)(Figure 3A) was conducted indicating metastases which were confirmed through ultrasonography of the abdomen.
A final diagnosis was made by biopsy and histopathological examination respectively.13 A partial resection of the mass that interfered with the occlusion was performed. The histopathological examination revealed an ulcerated fragment mucosa with the presence of a poorly differentiated neoplastic process, consisting of a diffuse proliferation of medium-sized, monomorphic blastoid cells with round vesicular to hyperchromatic nuclei. The nuclei contained small nucleoli and numerous mitotic figures were present. Between the cells there are tingible body macrophages giving rise to a starry sky appearance. (Figure 4) The immunophenotype identified the presence of a B-cell lymphoproliferative process expressing CD20, CD10, BCL6, MYC and a proliferation rate of 100%, but no expression of BCL2, TDT, cytokeratin, desmin, myogenin, CD99, MPO, CD3 or EBV. PCR showed monoclonal immunoglobulin heavy and light chain rearrangements. Fluorescence in-situ hybridization (FISH) confirmed diagnosis of Burkitt Lymphoma (MYC rearrangement, stage III, LDH>2N, high risk group)14 resulting in an overproduction of the MYC protein due to genetic rearrangement. The involvement of adenopathies on both sides of the diaphragm on PET-CT defines it as a stage III lesion based on the St. Jude classification. There was no invasion of the bone marrow. The LDH concentration was 786 U/L (normal range 192 – 321 U/L) indicating highly proliferative disease. Risk stratification was performed for treatment planning and is linked to the stage of the disease, site as well as LDH level.13–15 Chemotherapy was initiated combined with rituximab according to the intergroup B-NHL Ritux 2010 trial group B at the department for pediatric oncology and hematology.14
During hospitalization sufficient pain relief was achieved with IV administration of paracetamol and tramadol by weight and oral hygiene was restarted subsequently. After a part of the chemotherapy was administered the swelling diminished significantly. (Figure 1B)