Question

Which one of the following is likely to be a neoplasm of T-lymphocytic lineage?

• A. Chronic Lymphocytic Leukemia
• B. Burkitt's Lymphoma
• C. Mycosis Fungoides
• D. Small Lymphocytic (Well Differentiated) Lymphoma

Hint:

Three of the four are B-cell diseases -- look for the one that affects the skin.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks which of four lymphoid neoplasms arises from T lymphocytes rather than B lymphocytes, testing knowledge of lymphoma/leukemia cell-of-origin classification.

Step 2: Key Concept or Approach:
Most lymphoid neoplasms, including the great majority of leukemias and non-Hodgkin lymphomas, are of B-cell origin. Only a minority arise from T cells, and mycosis fungoides -- the most common cutaneous T-cell lymphoma -- is the classic example tested in exams, presenting with patches, plaques, and eventually tumors of the skin caused by malignant CD4-positive helper T cells infiltrating the epidermis (forming Pautrier microabscesses).

Step 3: Working Through the Options:
Chronic lymphocytic leukemia is a B-cell neoplasm, expressing CD19, CD20, and CD23 along with CD5, and it is essentially the same disease as small lymphocytic lymphoma in leukemic phase. Burkitt's lymphoma is also a B-cell neoplasm, characterized by the MYC translocation t(8;14) and a "starry sky" histological pattern from tingible body macrophages. Mycosis fungoides is the T-cell neoplasm among these four choices, arising from mature CD4+ helper T cells that home to the skin, making it the correct answer. Small lymphocytic (well differentiated) lymphoma is the tissue counterpart of CLL and is likewise a B-cell neoplasm.

Step 4: Conclusion:
The correct answer is mycosis fungoides, the only T-cell lineage neoplasm among the listed options.