Pathological fracture of the knee revealing Burkitt lymphoma: a case report

¹Clinical Hematology Department and Bone Marrow Transplantation, CHU Mohamed VI, Marrakech, Morocco

^&Corresponding author
Mustapha Mechtoune, Clinical Hematology Department and Bone Marrow Transplantation, CHU Mohamed VI, Marrakech, Morocco

Introduction    

Burkitt's lymphoma (BL) is a B cell lymphoma characterised by a monoclonal proliferation of B lymphoid cells. The etiology of this disease is unknown [1]. BL was first noted in African children by Dennis Burkitt in 1958 [2]. The diagnosis is based on morphologic findings, immunophenotyping results, and cytogenetic features [1]. BL accounts for 30-40% of non-Hodgkin´s lymphoma in HIV positive patients [3]. Burkitt lymphoma consists of three clinical subtypes:endemic form in Africa, sporadic form, associated with immunodeficiency especially those with AIDS and patients on immunosuppressive therapy [3]. Bone involvement as a revealing event in this type of lymphoma is very rare. The BL is a rapidly proliferating tumor with poor prognosis; we report a case of bone Burkitt lymphoma in a 49-year-old female patient with metastatic abdominal involvement.

Patient and observation     

A 49 year-old female patient with a 1-month history of pain of the left knee and abdominal pain, progressing in a context of general condition maintenance and apyrexia. Local examination revealed partial functional impotence of the knee with severe pain on palpation and on active and passive mobilization. Systematic examination including respiratory, cardiac, abdominal and central nervous system were normal. Standard X-ray of the knee revealed a fracture of the upper end of the tibia, CT scan of the knee revealed a process of osteolytic epiphyseal-metaphyseal tissue damage of the tibia with invasion of soft tissue with multiple nodular intramedullary epiphyseal and metaphyseal lesions of the femur with minimal joint effusion. The evolution is marked by the appearance of mass of the right hypochondrium rapidly progressive and right hypochondrium pain that increased during palpation. The abdominal CT scan revealed a subhepatic tissue mass measuring 13 cm/12 cm/12.5 cm which encompasses the right colon and contacts the abdominal wall with mesenteric lymphadenopathy. Laboratory tests showed: white cell count: 14700/ul; hemoglobin: 11.1 g/dl; platelet count: 255700/ul; lactate dehydrogenase: 590 u/l; calcium: 2.7 umol/l; creatinine: 52 umol/l; aspartate aminotransferase: 57 IU/l; alanine aminotrasferase: 88 IU/l; blood urea nitrogen: 7.3 mg/l. A biopsy of the knee was performed, the histological examination showed a malignant lymphoid infiltrate with large size cells, multiple nucleoli, a very high proliferative rate, and frequent mitotic figures. and extensive necrosis. Lymphoid cells expressed CD20+, BCL 6+, and CD10 +, MUM1+, and they were negative for BCL 2, with a 100% KI 67 confirms the diagnosis of Burkitt lymphoma (BL). Bone marrow aspiration was normal. Cervico-thoraco-abdominal CT scan revealed pancreatic involvement with infiltration of mesenteric fat, the myelogram and the lumbar puncture were normal. Hepatitis B and c and HIV viral serology were negative. Chemotherapy consisted of the following regimen R-CODOX-M (rituximab 375 mg/m², doxorubicin 40 mg/m², cyclophosphamide 800 mg/m², cytarabine 70 mg intrathecal, methotrexate 300 mg/m² iv./R-IVAC (rituximab 375 mg/m² iv, etoposide 60 mg/m² iv, ifosfamide 1.5 g/m², mesna 300 mg/m² iv, cytarabine 2 g/m² iv, methotrexate 12mg intrathecal).

Consent for publication: written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Discussion     

Burkitt lymphoma (BL) is a highly mature B-cell non-Hodgkin lymphoma it present 1 to 2% of all adult lymphomas. Clinical manifestations are not specific however the most common symptoms are pain and mass. Burkitt lymphoma can be subcategorized into 3 variants: endemic; sporadic; and BL with immunodeficiency, typically infection with HIV. Bone involvement in this type of lymphoma is a rare event. Bone pain as reveling event in Burkitt lymphoma is rare, maxillofacial location seems to be the most frequent, particularity of our observation is the localization in long bone, however, involvement of long bones remains exceptional [4]. Very few reports about this entity exist in literature. In this observation, a fracture of the upper and tibia were observed after radiological exploration and abdominal mass has appeare after an extension assessment. Abdominal mass is a common finding at the first medical examination in BL. Patients with BL present bone pain and swelling of the involved bone or a combination of both, neurological symptoms are common when there is involvement of vertebra [5]. The diagnostic study must include imaging of the local area, radiological characteristics of bone involvement in Burkitt lymphoma are generally non-specific, it may show a predominant or well-defined lytic lesion. The periosteal reaction is generally laminar. Magnetic resonance imaging (MRI) is the best imaging test for diagnostic guidance of BL. Bone marrow damage is hypo intense in T1 and hyper intense in T2. Hyper intensity can also be observed due to the peritumoral reaction and edema. The degree of involvement of the adjacent soft tissues is better determined with MRI [6]. Our observation is interesting to draw the attention of clinicians and especially othopedists to the interest of performing biopsies before doing any surgical procedure ,histopathological and immunohistochemical analyses are necessary to confirm a diagnosis of BL [6]. Burkitt lymphoma is characterized by translocations of chromosomes 8 and 14 resulting in upregulation of the c-myc protein transcription factor with upregulation of cell proliferation. The treatment of Burkitt lymphoma is still unknown and is mainly adapted from pediatric treatment regimens [6]. Burkitt lymphoma with advanced stage and older age groups is associated with poorer prognosis [7]. With early diagnosis and prompt appropriate treatment, long-term survival rates of 70-80% may be possible, while a delay in treatment may be lethal to such patients [8].

Conclusion     

BL is a rapidly proliferating tumor with poor prognosis, it's suspected in any abdominal masses, and the diagnosis should be established quickly followed by rapid initiation of definitive treatment for a better prognosis.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

All the authors contributed to the realization of this work. All the authors have read and agreed to the final manuscript.

Acknowledgements      

The authors are grateful to the medical and paramedical team of Clinical Hematology Department, CHU Mohamed VI for their continuous efforts.

References