This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Distinguishing consistently between lump and mass can be difficult in diagnostic contexts, as the terms are often used interchangeably or lack precise definitions. As a result, lump and mass have, in certain conditions, been treated as synonymous.

Avoid using 'lump' in new content, where more specific terminology is available.

Lump should not be added as a synonym for mass concepts in the Finding or Disorder hierarchies. Existing legacy synonyms and concepts will remain unchanged.

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This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

There are two types of abscesses:

1. septic

2. sterile

Most abscesses are septic, which means that they are the result of an infection.

If a concept's meaning, based on its FSN and text definition, does not specify whether the abscess is sterile or septic, then the concept should not be modeled as septic.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Disorders which involve congenital anomalies are defined with:

• Occurrence (attribute) = Congenital (qualifier value)

• Associated morphology (attribute) = Morphologically abnormal structure (morphologic abnormality)

• Pathological process (attribute) = Pathological development process (qualifier value)

Therefore, congenital does not need to be represented as the Associated morphology (attribute) target value. Congenital anomaly morphology concepts usually have non-congenital parents.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The morphologic abnormality subhierarchy is located two levels below the Body structure hierarchy with siblings Apoptosis and Structure resulting from tissue repair process:

• SNOMED CT concept

  • Body structure (body structure)

    • Body structure, altered from its original anatomical structure (morphologic abnormality)

      • Apoptosis (morphologic abnormality)

      • Morphologically abnormal structure (morphologic abnormality)

      • Structure resulting from tissue repair process (morphologic abnormality)

The concepts in the morphologic abnormality hierarchy represent abnormal body structures.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

When considering the creation of a new morphological abnormality concept, consider the following:

• When the name of a potentially new morphology is the same as the disease, creation of that new morphologic abnormality concept may not be beneficial since it would not be very morphologically descriptive.

• Determine if there is benefit in creating a new morphology for a very small number of rarely used leaf nodes. If the new morphology is needed to differentiate two non-leaf concepts, that would be sufficient to create the new morphology. Otherwise, use the nearest existing morphologic abnormality.

• Including a body site in a morphological abnormality concept is forbidden unless there is a clear modeling and pathological need.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Concepts from the Morphologic Abnormality hierarchy should not be used in place of concepts from the Clinical Findings hierarchy, even though they appear to refer to similar clinical situations.

• For example

  • 4147007 | Mass (morphologic abnormality)| is not a finding, but 300848003 | Mass of body structure (finding)| is a finding

Morphologies are used as the values of the defining attributes of findings and procedures. Findings are used to represent the combination of a morphology and a location.

• For example

  • 300923002 | Cyst of scalp (disorder)| represents cystic type of morphology that has the location, scalp

Many morphologies have names that could be misinterpreted as implying a process rather than a structure.

Inflammation might mean the structural-morphologic features of inflammation, such as inflammatory cell infiltrates; or it might mean the process that causes the structural changes. Within the morphologic abnormality hierarchy, the structural interpretation is intended, not the process interpretation.

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

When modeling a concept requiring two role groups with the same finding site/body structure but two different morphologies (because a combined morphology does not exist), then those two morphologic abnormalities can be combined to create a new single, combined |(morphologic abnormality)| concept. Keep the newly created morphologic abnormality concept primitive as all morphologic abnormality concepts should be primitive. Limit the combination to two morphological concepts into a single concept; combining more than two morphological concepts into a single combined concept is not permitted.

Example, If 400067002 |Acantholytic epidermal nevus (disorder)| had the same Finding site of |Skin structure (body structure)| with two different morphologic abnormalities of |Epidermal nevus (morphologic abnormality)| and |Acantholysis (morphologic abnormality)|, then those two morphologic abnormality concepts can be combined to create a single, primitive, morphologic abnormality concept of |Acantholytic epidermal nevus (morphologic abnormality)|. This will prevent modeling with two relationship groups.

Instead of modeling as per this diagram in the stated view with two morphologies of the same finding site:

Model as in the stated view of this diagram with a combined morphology:

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Fractures should be agnostic as to whether they are pathologic or not, unless specified in the FSN or could only be caused by trauma (e.g. open fractures). Although most fractures are traumatic, there are some pathological fractures. Based on its FSN and text definition, if the word pathological is present, use Pathologic fracture (morphologic abnormality).

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

SNOMED CT accepts tumor concepts, as long as they are included in the International Classification of Diseases for Oncology (ICD-O). ICD-O has two coding systems for coding the site (topography) and the histology (morphology) of the neoplasm:

• Topographical - Anatomical site of origin or the organ system

• Morphological - Tumor cell type or histology and behavior, i.e. malignant versus benign

The topography code describes the site of origin of the neoplasms. The morphology

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Multiple x morphologies, such as 125291005 |Multiple cysts (morphologic abnormality)|, are currently subtypes of the “X” morphology. The “X” morphology concept represents a class rather than a singular instance, and this arrangement follows the open world assumption of the description logic in SNOMED CT.

• For example,

  • Cyst of upper eyelid does not mean a single cyst on a single upper eyelid. It represents a class of cyst condition that at least appeared in an upper eyelid. This class would also include a cyst condition involving both upper and lower eyelids.