This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non Hodgkin Iymphoma, Subject name: Pathology
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? 
Select and explain. 
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.
D: Hallmark cells are a feature.
Answer: D: Hallmark cells are a feature. 
Explanation: 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.