A lymph node from a 10-year-old boy reveals large pleomorphic lymphocytes with CD30 positivity, frequent mitoses, and scattered cells bearing kidney-shaped nuclei. Which of the following statements is true?: (A) t(2;5) translocation impas a worsened prognosis., (B) ALK protein immunostaining is seen in a minority of cases., (C) This tumor occurs exclusively in children, (D) Hallmark cells are a feature.
Answer is D. This patient has anaplastic large cell lymphoma (ALCL). The constituent cells are positive for CD30. Scattered cells showing kidney or donut-shaped nuclei with an eosinophilic region adjacent to the nucleus are known as "Hallmark cells." The majority of cases in children shows a t(2;5) translocation which correlates with ALK positivity and improved survival. Bimodal incidence.