A7 year old presents with fever, weight loss. On examination he was pale and had significant lymphadenopathy. Bone marrow histology is as given below. What is the most probable diagnosis?
**Core Concept**
Acute lymphoblastic leukemia (ALL) is a clonal malignancy of immature lymphoid cells, characterized by uncontrolled proliferation of malignant lymphoblasts in the bone marrow, peripheral blood, and other lymphoid organs. The disease often presents with symptoms such as fever, weight loss, and lymphadenopathy due to infiltration of malignant cells.
**Why the Correct Answer is Right**
The bone marrow histology in this case is likely to show an increased number of lymphoblasts, which are immature lymphoid cells with distinct morphological features. These cells may exhibit abnormal nuclear morphology, such as irregular nuclear contours, fine chromatin, and prominent nucleoli. The presence of lymphoblasts in the bone marrow is a hallmark of ALL, and their abnormal morphology is a key diagnostic feature. The disease often involves the lymphoid organs, leading to lymphadenopathy, and the presence of malignant cells in the peripheral blood can cause symptoms such as fever and weight loss.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not provide a specific diagnosis, making it an ambiguous choice. ALL is a specific diagnosis that can be made based on the histological features of the bone marrow.
**Option B:** This option is incorrect because it refers to a different type of leukemia, chronic lymphocytic leukemia (CLL), which typically affects older adults and presents with a different set of symptoms and histological features.
**Option C:** This option is incorrect because it refers to a different type of lymphoma, Hodgkin lymphoma, which is characterized by the presence of Reed-Sternberg cells and typically presents with lymphadenopathy and systemic symptoms.
**Option D:** This option is incorrect because it refers to a different type of leukemia, acute myeloid leukemia (AML), which typically presents with different histological features and a different clinical course.
**Clinical Pearl / High-Yield Fact**
ALL is a common malignancy in children, and its diagnosis requires a high index of suspicion, especially in the presence of symptoms such as fever, weight loss, and lymphadenopathy. A bone marrow biopsy is essential for making a definitive diagnosis, and it should be performed in all cases where ALL is suspected.
**Correct Answer:** C.