A 23-year-old man comes to the office due to a rapidly enlarging left jaw mass that has developed over the past several weeks. The patient is a political refugee from East Africa. He has no known medical problems and takes no medications. Temperature is 37.1 C (98.8 F). Physical examination shows a large left-sided tumor on his jaw with surrounding lymphadenopathy but no erythema or warmth. The rest of the examination is unremarkable. HIV testing is negative. The lesion is biopsied, and numerous mitotic figures and apoptotic bodies are observed on histopathologic examination. Which of the following genetic features is most likely to be present in this tissue?

Question

A 23-year-old man comes to the office due to a rapidly enlarging left jaw mass that has developed over the past several weeks.  The patient is a political refugee from East Africa.  He has no known medical problems and takes no medications.  Temperature is 37.1 C (98.8 F).  Physical examination shows a large left-sided tumor on his jaw with surrounding lymphadenopathy but no erythema or warmth.  The rest of the examination is unremarkable.  HIV testing is negative.  The lesion is biopsied, and numerous mitotic figures and apoptotic bodies are observed on histopathologic examination.  Which of the following genetic features is most likely to be present in this tissue?

Quizplus · Accepted Answer

This patient has the typical presentation of endemic (African-type) Burkitt lymphoma, of which jaw involvement is a characteristic feature. Almost all cases of endemic Burkitt lymphoma are associated with Epstein-Barr virus (EBV) infection. EBV has been implicated in the immortalization of lymphoma cells. Histologically, Burkitt lymphoma has a "starry sky" appearance due to the presence of macrophages and apoptotic bodies in a sea of medium-sized lymphocytes. Up to 90% of Burkitt lymphoma cases are associated with translocation of the c-Myc gene on chromosome 8, usually onto the Ig heavy chain region of chromosome 14 [t(8;14)]. This translocation leads to overexpression of the c-Myc oncogene and tumor growth. Burkitt lymphoma is a high-grade lymphoma. Although it is very aggressive, the tumor responds well to short-term, intensive high-dose chemotherapy. Patients with limited disease have an excellent prognosis. (Choice A) In follicular lymphoma, there is overexpression of the antiapoptotic BCL2 as a result of the t(14;18) translocation. Follicular lymphoma causes generalized lymphadenopathy and tends to affect the elderly. Jaw involvement would be very unusual. (Choices B and E) The BCR-ABL rearrangement is found in chronic myelogenous leukemia and some forms of acute lymphoblastic leukemia. The translocation causes increased tyrosine kinase activity. (Choice D) Overexpression of the n-Myc oncogene is usually seen in neuroblastoma. Educational objective: Histologically, Burkitt lymphoma has a "starry sky" appearance due to the presence of macrophages and apoptotic bodies in a sea of medium-sized lymphocytes. The rates of mitosis and apoptosis in the cancerous tissue are high. Almost all cases of Burkitt lymphoma are associated with translocations of the c-Myc gene on chromosome 8, usually onto the Ig heavy chain region of chromosome 14 [t(8;14)].

A 23-Year-Old Man Comes to the Office Due to a Rapidly