Carcinoma, Sarcoma, Myeloma, Lymphoma and Leukemia – What Cancer is That?
At OncoCare Cancer Centre, we sometimes see patients who have received a report and are confused by the cancer names or terminology. Some patients have been informed by their treating doctor or surgeon that they have a lump removed and that it is a tumor (or tumour). They next receive a report that may be difficult to understand. What is the difference between the different terminologies?
1. Is this a malignancy?
This is probably the most basic question that a patient should ask. Not all lumps are malignant or cancerous. Fibroadenoma of the breast, fibrocystic disease of the breast are some examples of benign conditions. A benign tumour in general does not invade or spread, and frequently removal by surgery is the cure. A formal definition of cancer characteristics are: a tumour that has its own growth signals, that resists signals that informs it to stop growing (like a middle-age belly!), resist cell death, multiplies forever and is able to stimulate its own blood supply (angiogenesis).
Like many things in biology, there are some tumours that somehow do not fulfil the entire criterion. A proper discussion may be necessary, sometimes with the help of a pathologist.
Carcinoma, Sarcoma, Myeloma, Lymphoma, or Leukemia
2. Where does the tumour arise from?
Carcinoma (from the Greek word describing a “crab”) is the term for cancers that arise from epithelial cells. These include the common cancer sites that we know such as breast, colon, stomach, skin and lung cancer. Epithelial cells are the cells lining the external or inner surfaces of our body and organs. Remember that the cancer does not declare under microscopic examination its organ of origin such as the lung, stomach, breast, ovary or colon. In fact, the carcinoma may be described because it has features of “skin type” (squamous cell), or gland-forming (adenocarcinoma) features. There can also be complete disorganisation with unrecognisable features (anaplastic). In addition, sometimes the cancer is described based on its cell size, such as large or small cell carcinoma. There can certainly be mixed cell types seen in a biopsy (adenosquamous).
Other elements of our body can give rise to cancers of the muscle, bone, cartilage and connective tissues known as sarcoma.
The blood and lymph system is where lymphoma, myeloma and leukaemia (or leukemia) get their origins. Here is where the naming gets a bit complex. Most people might have heard of Hodgkin and non-Hodgkin’s lymphoma but there are actually many types of lymphoid tissues within our system that can turn malignant. Although most people might know what breast carcinoma is, they might not be familiar with NK/T cell lymphomas (or try Mycosis Fungoides and Sezary Syndrome!). Under the World Health Organization (WHO) classification of lymphomas, there are more than 60 types.
TABLE: WHO Classification of mature B-cell, T-cell, and NK-cell neoplasms (2008)
Mature B-cell neoplasms
Chronic lymphocytic leukemia/ small
B-cell prolymphocytic leukemia
Splenic marginal zone lymphoma
Hairy cell leukemia
Splenic lymphoma/leukemia, unclassifiable
Splenic diffuse red pulp small B-cell
Hairy cell leukemia-variant*
Heavy chain diseases
Alpha heavy chain disease
Gamma heaby chain disease
Mu heavy chain disease
Plasma cell myeloma
Solitary plasmacytoma of bone
Extranodal marginal zone lymphoma of
mucosa-associated lymphomid tissue
Nodal marginal zone lymphoma
Pediatric nodal marginal zone lymphoma
Pediatric follicular lymphoma
Primary cutaneous follicular center lymohoma
Mantle cell lymphoma
Diffuse large B-cell lymphome (DLBCL), NOS
T-cell / histiocyte-rich large B-cell lymphoma
EBV+ DLBCL of the elderly
DLBCL associated with chronic
Primary mediastinal (thymic) large B-cell
Intravascular large B-cell lymphoma
Primary cutaneoud DLBCL, leg type
ALK+ large B-cell lymphoma
Large B-cell lymphoma arising in
Primary effusion lymphoma
B-cell lymphoma, unclassifiable, with features
intermediate between DLBCL and Burkitt
B-cell lymphoma, unclassifiable, with features
intermediate between DLBCL and classic
Mature T-cell and NK-cell neoplasms
T-cell prolymphocyic leukemia
T-cell large granular lymphocytic leukemia
Chronic lymphoproliferative disorder of NK
Aggressive NK cell leukemia
Systemic EBV+ T-cell lymphoproliferative
disease of childhood
Hydroa vacciniforme-like lymphoma
Adult T-cell leukemia / lymphoma
Extranodal NK / T-cell lymphoma, nasal type
Enteropathy-associated T-cell lymphoma
Hepatosplenic T-cell lymphoma
Subcutaneous panniculitis-like T-cell
Primary cutaneous CD30+ T-cell
Primary cutaneous anaplastic large cell
Primary cutaneous gamma-delta T-cell
Primary cutaneous CD8+ aggressive
epidermatropic cytotoxic T-cell lymphoma*
Primary cutaneous CD4+ small / medium
Peripheral T-cell lymphoma, NOS
Angioimmunoblastic T-cell lymphoma
Anaplastic large cell lymphoma, ALK+
Anaplastic large cell lymphoma, ALK-*
Nodular lymphocyte-predominant Hodgkins
Classic Hpdgkins lymphoma
Nodular scierosis classic
Mixed cellularity classic Hodgkin
Lymphocyte-depleted classic Hidgkin
Infectious mononulceosis-like PTLD
Monomorphic PTLD (B and T / NK-cell types)^
Classic Hodgkins lymphoma type PTLD^
*Provisional entities for which the WHO Working Group thought there was insufficient evidence to recognize as distinct diseases at this time.
^These lesions are classified according to the leukemia or lymphoma to which they correspond. Diseases shown in italics were newly included in the 2008 WHO classification.
Myeloma is a type of malignant B cell neoplasm arising from plasma cells. Other specialized tissues in our body can turn malignant and they do have unusual (non-conventional) names such as glioma (from brain and central nervous system tissues), melanoma (from nevus or moles) and germinoma (germ cell tissue such as testes or ovaries).
3. Is this a primary or metastatic tumour?
A primary tumour or cancer arises from where its tissue of origin is found but a secondary or metastatic tumour comes from dissemination from another site. The tumour seen in the lung may arise from the lung (primary lung cancer) or from elsewhere (metastasis). Even if the pathology reports the cancer cell type, (say adenocarcinoma cells from a biopsy of a lung lesion), it can be a primary or metastasis. There are some special tests that can be performed on the tumour to differentiate where it originated. Immunohistochemistry is a technique to stain tumour cells on a slide with antibodies carrying a stain. For example, breast cancer cells might have oestrogen (or estrogen) receptors (ER) and staining positive for this hormone receptor may give a clue that the adenocarcinoma started from breast tissues.
Identifying the cancer (whether it is carcinoma, sarcoma, myeloma, lymphoma or leukaemia) is just the beginning but it is important in many situations using advanced, histopathological and molecular techniques as it can affect treatment and prognosis.
Dr Peter Ang
MMed (Int Med)
FAMS (Medical Oncology)
Dr Kevin Tay
ABIM Int. Med (USA)
ABIM Med Onc(USA)
FAMS (Medical Oncology)