The origin of myeloma is-

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2022

Explanation

Multiple myeloma is a malignant proliferation of plasma cells, which are a type of white blood cell.
These cancerous plasma cells accumulate in the bone marrow, displacing normal blood-forming cells.
Plasma cells are terminally differentiated B-lymphocytes, and their primary function is to produce antibodies (immunoglobulins).
In myeloma, the neoplastic plasma cells produce a large amount of a single type of immunoglobulin, known as a monoclonal (M) protein.

Option A: Cancers that originate from epithelial cells are known as carcinomas, not myelomas. Epithelial cells line the surfaces of the body and organs.
Option B: While plasma cells are a mature form of B-lymphocytes, cancers that arise directly from lymphocytes in lymph nodes or blood are typically classified as lymphomas or lymphocytic leukemias.
Option D: Cancers originating from fibrous connective tissues are called sarcomas (e.g., fibrosarcoma). Myeloma arises from hematopoietic cells, not connective tissue.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular origin of multiple myeloma as background academic context rather than a clinical decision trigger.
Understanding that myeloma originates from plasma cells is crucial for diagnosis. Key diagnostic tests, like serum protein electrophoresis, look for the monoclonal (M) protein produced by these cancerous cells.
Treatment strategies for multiple myeloma, such as proteasome inhibitors and immunomodulatory drugs, are designed to specifically target and kill malignant plasma cells.
What if? If a bone marrow biopsy showed a massive proliferation of immature granulocytes instead of plasma cells, the diagnosis would be acute myeloid leukemia (AML), not myeloma. This would necessitate a completely different treatment approach, highlighting the importance of identifying the cell of origin.

How to Approach the Question

First, identify the core term in the question: 'myeloma'.
Recall the definition of myeloma. The prefix 'myel-' refers to bone marrow, and '-oma' means tumor. This points to a cancer within the bone marrow.
Consider the cell types that are prominent in the bone marrow. This includes hematopoietic stem cells and their progeny, including plasma cells.
Evaluate the options. Associate each cell type with the cancer it causes: Epithelial cells -> Carcinoma; Lymphocytes -> Lymphoma/Leukemia; Fibrous tissue -> Sarcoma.
By elimination and direct recall, connect 'myeloma' specifically to 'plasma cells', which are a key component of the bone marrow's immune cell population.

Concept Tested & Keywords

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E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 611-613

E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 128-130

Practise the full RUHS, Jaipur, PB B.Sc Nursing Entrance-2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.