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Lesions, Masses, and Tumors, Oh My! 

Lesions, Masses, and Tumors, Oh My! 

When doctors describe lumps and bumps inconsistently, look to the definitive diagnosis for clarity.

Coding lesions, masses, and tumors can be tricky because some providers use these three terms interchangeably in the same operative note. By the time you’ve finished reading the note, you don’t know what type of lump or bump you’re coding. Is a lesion a tumor? Is a tumor a mass? Not knowing if you’re coding a lesion vs. a tumor is a problem because ICD-10-CM differentiates those lumps and bumps. You can simplify this conundrum by:

  • Defining lesions, masses, and tumors;
  • Understanding how ICD-10-CM categorizes them; and
  • Applying the associated ICD-10-CM guidelines for accurate coding.

What Is the Difference Between Lesions, Masses, and Tumors?

Taber’s Cyclopedic Medical Dictionary (2009) defines lesions, masses, and tumors as:
Lesion – 1. A circumscribed area of pathologically altered tissue. 2. An injury or wound. 3. A single infected patch due to skin disease. Primary or initial lesions include macules, vesicles, blebs or bullae, chancres, pustules, papules, tubercles, wheals, and tumors. Secondary lesions are the result of primary lesions. They may be crusts, excoriations, fissures, pigmentations, scales, scars, and ulcers.

  • Diffuse lesion: A lesion spreading over a large area.
  • Focal lesion: A lesion of a small definite area.
  • Gross lesion: A lesion visible to the eye without the aid of a microscope.

Lesions are not isolated to the skin; there are also vascular lesions (vascular malformations of the venous, arterial, and lymphatic systems, i.e., infantile hemangiomas).
Mass – A quantity of material, such as cells, that unite or adhere to each other.
Tumor – 1. A swelling or enlargement (tumor is Latin for swelling). 2. An abnormal mass. Growth or proliferation that is independent of neighboring tissue is a hallmark of all tumors, benign and malignant.

By these definitions, it’s still hard to know the difference between a lesion, a mass, and a tumor.

Other Medical Terms You Should Know

To accurately identify lesions, masses, and tumors for diagnosis coding, you will need to know the meaning of the following terms:

Neoplasm: An abnormal tissue mass resulting from abnormal cellular proliferation (neoplasia). The growth persists in an excessive manner, usually causing a lump or tumor. Neoplasms may be benign, pre-malignant, or malignant.
Histology: The study of the microscopic structure of cells and tissues.
Benign: A non-cancerous tumor or growth that does not spread or infiltrate (e.g., adenoma).
Malignant: Cancerous cells that have the ability to spread, invade, and destroy tissue. Malignant cells tend to have fast, uncontrolled growth due to genetic abnormalities.

ICD-10-CM Categorizes Neoplasms Based on Behavior

Without a definitive diagnosis, a mass (or tumor) is coded from Chapter 18: Symptoms, Signs, and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99). When the provider refers to the condition as a tumor, growth, neoplasm, or new growth, without having obtained a definitive diagnosis, code selection is taken from category D49 Neoplasms of unspecified behavior of the Neoplasm section in the ICD-10-CM code book.

D49 differs from categories D37-D44 and D48 Neoplasm of uncertain behavior of other and unspecified sites in that the “histologic confirmation whether the neoplasm is malignant or benign cannot be made.” The operative phrase is “histologic confirmation.” In other words, the specimen has been observed, probably by a pathologist, and a determination for whether the specimen is malignant or benign could not be made. In such a case, code selection is from D37-D44 and D48.

If the results of a biopsy are positive, a malignant code is selected from the Neoplasm section of the ICD-10-CM code book. And if the results are negative, a benign code is selected.

When the provider states that a specimen has been submitted for pathological identification due to suspicion of malignancy or for a lymphoma protocol, it’s an indication that you will code the biopsy results from the Neoplasm section. The provider is having the specimen tested to determine if the cells are cancerous. The lymph nodes are often biopsied as well to determine whether the primary malignancy has spread. Nearby lymph nodes are removed if the pathologic examination reveals malignancy. Codes for the lymph node biopsy results are also found in the Neoplasm section.

Keep in mind that a pathological specimen is not submitted with every tissue excision; and in such cases, the diagnoses the provider has documented on the operative report are for that encounter. When in doubt, the best practice is to query the provider.

ICD-10-CM Guidelines

In the definition above, a tumor is referenced as a “mass.” According to the National Cancer Institute, a tumor is also called a “neoplasm.” This is important because ICD-10-CM states in the notes for D49, “The term ‘mass,’ unless otherwise stated, is not to be regarded as a neoplastic growth.” Look to ICD-10-CM Section II. Selection of Principal Diagnosis and Section IV. Diagnostic Coding and Reporting Guidelines for Outpatient Services for direction on how to correctly code the condition:

Section II. Selection of Principal Diagnosis

  1. Codes for symptoms, signs, and ill-defined conditions

Codes for symptoms, signs, and ill-defined conditions from Chapter 18 are not to be used as a principal diagnosis when a related definitive diagnosis has been established.

Section IV. Diagnostic Coding and Reporting Guidelines for Outpatient Services

  1. Codes that describe symptoms and signs

Codes that describe symptoms and signs, as opposed to diagnoses, are acceptable for reporting purposes when a diagnosis has not been established (confirmed) by the provider.

  1. Patients receiving diagnostic services only

… For outpatient encounters for diagnostic tests that have been interpreted by a physician, and the final report is available at the time of coding, code any confirmed or definitive diagnosis(es) documented in the interpretation. Do not code related signs and symptoms as additional diagnoses.

Based on the above guidance, without a definitive diagnosis, a mass should be coded from Chapter 18: Symptoms, Signs, and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99). Non-neoplastic lesions are classified in specific body system chapters and may be found under the appropriate site or type from the Alphabetic Index under Lesion.

Without a definitive diagnosis, codes for tumors, growths, neoplasms, and new growths are taken from D37-D44 and D48. To code a lesion, select the appropriate site or type from the Alphabetic Index under Lesion. When a definitive diagnosis has been made for a mass, lesion, or tumor (e.g., Warthin’s tumor), search for the specific diagnosis code. Codes for symptoms, signs, and ill-defined conditions should not be used instead of a principal diagnosis in the inpatient setting and should not be used as additional diagnoses in the outpatient setting.

Apply Your Knowledge

Review the operative report to determine what you are coding:
DOS: 6/1/20XX
Pre-operative Diagnosis: Vocal cord lesion
Postoperative Diagnosis: Same
Procedure: Biopsy
Specimens: Vocal cord lesion
Findings: Mass located at VC lesion
Indication for Surgery: Vocal cord neoplasm

Code this as a neoplasm because the term “neoplasm” is the indication for surgery, but the surgeon is also performing a biopsy. A biopsy will determine if the neoplasm is benign or malignant.

Remember: The definition of neoplasm is abnormal tissue that grows by cellular proliferation more rapidly than normal and continues to grow after the stimuli that initiated the new growth cease.

If you have experienced confusion with coding lesions, masses, and tumors, as I have, I hope the above has provided clarity in distinguishing the conditions. ICD-10-CM is key to understanding how to code the conditions whether or not a definitive diagnosis has been made.

Winda F. Hampton, RHIA, CPMA, CCS-P, has more than four years’ experience as an outpatient surgical coder. She attended the University of Alabama at Birmingham where she received a Bachelor of Science in Health Information Management. Hampton is a member of the Durham, N.C., local chapter.

ICD-10-CM: International Classification of Diseases, (10th edition, 2019).
NIH National Cancer Institute, NCI Dictionary of Cancer Terms. “Tumor” search results:
Taber’s Cyclopedic Medical Dictionary (21st edition). (2009). Philadelphia

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