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?
**Question:** 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. Lymph node enlargement due to reactive lymphoid hyperplasia
B. T cell lymphoma with anaplastic large cell subtype
C. Hodgkin's lymphoma
D. EBV-associated lymphoproliferative disorder
**Correct Answer:**
**Core Concept:**
Lymphoma is a group of malignant lymphoproliferative disorders characterized by proliferation of lymphoid cells. In children and adolescents, the most common lymphoma is Hodgkin's lymphoma (HL), which is usually caused by Epstein-Barr virus (EBV) infection. However, there are also non-Hodgkin lymphomas (NHL), including T cell lymphomas.
**Why the Correct Answer is Right:**
The correct answer is B: T cell lymphoma with anaplastic large cell subtype. The presence of large pleomorphic lymphocytes, CD30 positivity, frequent mitoses, and scattered kidney-shaped nuclei are indicative of anaplastic large cell lymphoma (ALCL), a subtype of T cell lymphoma. ALCL is characterized by the proliferation of large, pleomorphic lymphocytes, which can be CD30+. The frequent mitoses and kidney-shaped nuclei are specific histopathological features of ALCL.
**Why Each Wrong Option is Incorrect:**
A) Reactive lymphoid hyperplasia is a benign condition characterized by lymph node enlargement due to proliferation of mature lymphocytes, which is a distinct clinical entity from lymphoma. In contrast, the given histopathological features are consistent with a malignant lymphoid neoplasm.
C) Hodgkin's lymphoma is a distinct clinical entity characterized by Reed-Sternberg cells and lymph node enlargement. The given histopathological features are not consistent with Hodgkin's lymphoma.
D) EBV-associated lymphoproliferative disorders are linked to EBV infection, including EBV-associated lymphomas like Burkitt's lymphoma and EBV-positive diffuse large B cell lymphoma. In this question, the histopathological features are consistent with T cell lymphoma, not EBV-associated lymphoproliferative disorders.
**Clinical Pearl:**
Histopathological examination is crucial for diagnosing lymphoid neoplasms, distinguishing lymphoma from reactive lymphoid hyperplasia, and identifying the subtype of lymphoma (Hodgkin's vs. Non-Hodgkin's lymphoma). While EBV-associated lymphoproliferative disorders are important to consider in the differential diagnosis, the presented histopathological features are more consistent with T cell lymphoma, particularly anaplastic large cell lymphoma (ALCL).
**Why the Correct Answer is Right:**
T cell lymphomas are a group of malignant lymphoid neoplasms characterized by proliferation of T cells. Anaplastic large cell lymphoma (ALCL) is a subtype of T cell lymphoma, which is characterized by the proliferation of large, ple