Neoplasm

Tumor vs. neoplasm

The word tumor has two primary meanings: a mass, regardless of whether it is neoplastic or not; or a neoplastic mass. The term neoplasm is preferred since it is less ambiguous than tumor.  The word tumor is acceptable as a synonym but not as a preferred term.  

For example, 

• • 92385005 |Benign neoplasm of small intestine (disorder)|

Primary malignant neoplasm

Previously in SNOMED CT, the hierarchy of 372087000 |Primary malignant neoplasm (disorder)| was defined by using an Associated morphology (attribute) relationship to <<86049000 |Malignant neoplasm, primary (morphologic abnormality)|.  86049000 |Malignant neoplasm, primary (morphologic abnormality)| and 367651003 |Malignant neoplasm of primary, secondary, or uncertain origin (morphologic abnormality)| have been inactivated in the November 2022 release and replaced with 1240414004 |Malignant neoplasm (morphologic abnormality)|.  

Primary malignant neoplasm disorders are now defined with a role group combining:

• finding site
• associated morphology
• pathological process with a target value of 1234914003 |Malignant proliferation of primary neoplasm (qualifier value)|

 For example,

Figure 1: Stated view of 93825008 |Primary malignant neoplasm of heart (disorder)|

Figure 2: Inferred view of 93825008 |Primary malignant neoplasm of heart (disorder)|

Metastatic malignant neoplasm

Precoordination of the metastatic malignant neoplasm with both the primary and metastatic sites is not allowed.  Having both metastatic malignant neoplasm from x body structure to y body structure in a single concept results in a combinatorial explosion of all possible malignant neoplastic morphological cell types, with all possible body sites of the primary malignancy, and with all possible sites of the metastases.  Users are instead directed to record two separate concepts. 

SNOMED CT joins ICD-O, ICD-10, and ICD-11 where metastatic malignant neoplasm of site x is uniformly interpreted to mean metastasis has occurred to site x.  To make this explicit in SNOMED CT, the following terming has been adopted:

FSN: Metastatic malignant neoplasm to x body structure (disorder)  
PT: Metastatic malignant neoplasm to x body structure   
SYN: Secondary malignant neoplasm of x body structure   
SYN: Metastatic malignant neoplasm of x  body structure   

For example,

FSN: Metastatic malignant neoplasm to foot (disorder)   
PT:    Metastatic malignant neoplasm to foot   
SYN: Secondary malignant neoplasm of foot   
SYN: Metastatic malignant neoplasm of foot    

Metastatic disorders are defined by a role group containing the finding site and specific metastatic morphologic abnormality.

For example,

Figure 3: Stated view of 105041000119109 |Metastatic squamous cell carcinoma to lung (disorder)|

Figure 4: Inferred view of 105041000119109 |Metastatic squamous cell carcinoma to lung (disorder)|

Use of the term cancer

Disorder concepts defined with 1240414004 |Malignant neoplasm (morphologic abnormality)| may have cancer added as an acceptable synonym.  The term cancer should not be used in the FSN or preferred term.  Neither should it be used in descriptions for concepts that are more specific subtypes of the top level malignant neoplasm grouper (i.e., where the morphology is a specialized cell type).

The term cancer may also be used in the 'metastatic cancer to x body structure' synonym description where the morphological type of metastatic neoplasm is unknown, i.e., it is defined with 14799000 |Neoplasm, metastatic (morphologic abnormality)|.

Neoplasia

When modeling neoplasia, distinguish structure from process. Do not use neoplasia in the FSN to identify the structure (even though it implies it).  Use 126537000 |Neoplasm of bone (disorder)|, not neoplasia of bone. 

Neoplastic disease refers to the process of neoplasia, leading to the formation of a neoplasm.

Neoplasm versus hamartoma

A neoplasm is defined as a growth of tissue no longer under normal control. A hamartoma is defined as a benign, self-limiting growth of disorganized mature cells normally found in the region, representing faulty development. SNOMED CT has disorder (and morphologic abnormality) concepts and subtypes representing neoplasia, hamartomas, and tumors.

The SNOMED CT concept 399981008 |Neoplasm and/or hamartoma (disorder)| has six subtypes: 

• • angiomatosis
    
  • hamartoma
  • hemangioma
  • lymphangioma
  • melanocytic nevus
  • neoplastic disease

The SNOMED CT concept 400177003 |Neoplasm and/or hamartoma (morphologic abnormality)| also has six subtypes:

• • angiomatosis
  • blood vessel tumor
  • hamartoma
  • lymphatic vessel tumor
  • melanocytic nevus
  • neoplasm

Nevus

The word nevus has many different meanings. The differences are generally based on answers to the following questions:

• • Is it necessarily on the skin? Or can it be located in mucosal sites or other sites?
  • Is it necessarily visible? Or can it be in internal locations such as gastric mucosa, etc?
  • Is it necessarily present at birth? Or can it occur later in life?
  • Is it necessarily dark and made of melanocytes? Or can it be non-pigmented, or made of other types of cells?
  • Is it necessarily made of tissue that is normally present at the site? Or can it be ectopic?
  • Does it exclude benign neoplasms?

Some common meanings of nevus based on some combinations of answers to the questions are as follows:

• • A birthmark, that is, any visible spot on the skin or oral mucosa present since birth, regardless of tissue of origin, excluding benign neoplasms.
  • Any benign cluster of melanocytes, regardless of location, and regardless of pigmentation, whether present since birth or appearing later.
  • Any cutaneous hamartoma. This excludes non-cutaneous sites, and excludes neoplasms and ectopic tissue, such as choristomas.

As a result of this wide variation in meaning, any SNOMED CT FSN containing the word nevus may be ambiguous. For example, the term vascular nevus may mean:

• • Congenital blood vessel tumor in the skin
  • Congenital blood vessel hamartoma or neoplasm that is visible somewhere (not only the skin, but also the mucosa, whether visible externally or not)
  • Congenital blood or lymphatic vessel tumor in the skin
  • Congenital blood or lymphatic vessel hamartoma or neoplasm that is visible somewhere
  • Any of the above but not necessarily congenital

A better FSN for vascular nevus (morphologic abnormality) would be vascular hamartoma (morphologic abnormality). Likewise, a better FSN for congenital vascular nevus (disorder) would be congenital vascular hamartoma (disorder).    

In those cases where common clinical usage of a term containing nevus is unambiguous, there is no need to inactivate the description or the concept.

Overlapping neoplasm

Overlapping neoplasm concepts refer to a neoplasm that overlaps two or more adjacent sites.  For clarity, the phrase overlapping sites should be included in the descriptions for the FSN and PT for new overlapping neoplasm content. 

For example,
188247000 | Malignant neoplasm of overlapping sites of bladder (disorder)|

For modeling an overlapping neoplasm concept, if the concept refers to contiguous sites involving more than one anatomical site, then a separate role group is used for each finding site.

However, assigning a role group for each finding site does not sufficiently define a concept but merely indicates the presence in both sites of a neoplasm. Where a relevant primitive existing overlapping neoplasm concept is available, this can be used as a stated primitive parent to sufficiently define the concept.

For example,
Sufficiently defined concept 721624000 |Primary adenocarcinoma of overlapping sites of esophagus (disorder)| has a stated primitive parent of 187824009 |Malignant neoplasm of overlapping sites of digestive system (disorder)|.