ICD-10-CM Diagnosis Code D49.9 - Neoplasm of unspecified behavior of unspecified site (original) (raw)

ICD List Logo

ICD List 2025-2026 Edition

  1. Home
  2. ICD-10-CM Codes
  3. D50–D89
  4. D49
  5. D49
  6. 2026 ICD-10-CM Code D49.9

Neoplasm of unspecified behavior of unspecified site

ICD-10-CM Code:

D49.9

ICD-10 Code for:

Neoplasm of unspecified behavior of unspecified site

Is Billable?

Yes - Valid for Submission

Chronic Condition Indicator: [1]

Not chronic

Code Navigator:

D49.9 is a billable diagnosis code used to specify a medical diagnosis of neoplasm of unspecified behavior of unspecified site. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026.

The following anatomical sites found in the Table of Neoplasms reference this diagnosis code given the correct histological behavior: Neoplasm, neoplastic unknown site or unspecified .

Unspecified diagnosis codes like D49.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

  1. Code Information
  2. Approximate Synonyms
  3. Clinical Classification
  4. Clinical Information
  5. Tabular List of Diseases and Injuries
  6. Index to Diseases and Injuries References
  8. Diagnostic Related Groups Mapping
  9. Convert to ICD-9 Code
  10. Table of Neoplasms
  11. Patient Education
  12. Other Codes Used Similar Conditions
  13. Code History

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

CCSR Code: NEO072

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

cerebellar degeneration associated with a remote neoplasm. clinical manifestations include progressive limb and gait ataxia; dysarthria; and nystagmus, pathologic. the histologic type of the associated neoplasm is usually carcinoma or lymphoma. pathologically the cerebellar cortex and subcortical nuclei demonstrate diffuse degenerative changes. anti-purkinje cell antibodies (anti-yo) are found in the serum of approximately 50% of affected individuals. (adams et al., principles of neurology, 6th ed, p686)

a paraneoplastic syndrome marked by degeneration of neurons in the limbic system. clinical features include hallucinations, loss of episodic memory; anosmia; ageusia; temporal lobe epilepsy; dementia; and affective disturbance (depression). circulating anti-neuronal antibodies (e.g., anti-hu; anti-yo; anti-ri; and anti-ma2) and small cell lung carcinomas or testicular carcinoma are frequently associated with this syndrome.

a subacute or chronic inflammatory disease of muscle and skin, marked by proximal muscle weakness and a characteristic skin rash. the illness occurs with approximately equal frequency in children and adults. the skin lesions usually take the form of a purplish rash (or less often an exfoliative dermatitis) involving the nose, cheeks, forehead, upper trunk, and arms. the disease is associated with a complement mediated intramuscular microangiopathy, leading to loss of capillaries, muscle ischemia, muscle-fiber necrosis, and perifascicular atrophy. the childhood form of this disease tends to evolve into a systemic vasculitis. dermatomyositis may occur in association with malignant neoplasms. (from adams et al., principles of neurology, 6th ed, pp1405-6)

diseases characterized by inflammation involving multiple muscles. this may occur as an acute or chronic condition associated with medication toxicity (drug toxicity); connective tissue diseases; infections; malignant neoplasms; and other disorders. the term polymyositis is frequently used to refer to a specific clinical entity characterized by subacute or slowly progressing symmetrical weakness primarily affecting the proximal limb and trunk muscles. the illness may occur at any age, but is most frequent in the fourth to sixth decade of life. weakness of pharyngeal and laryngeal muscles, interstitial lung disease, and inflammation of the myocardium may also occur. muscle biopsy reveals widespread destruction of segments of muscle fibers and an inflammatory cellular response. (adams et al., principles of neurology, 6th ed, pp1404-9)

a cutaneous melanocytoma caused by the inactivation of bap1 tumor suppressor gene. it is characterized by the presence of a predominantly intradermal proliferation of large epithelioid melanocytes with a large amount of eosinophilic cytoplasm, and vesicular nuclei with prominent nucleoli. progression to melanoma is infrequent.

a conjunctival melanocytic neoplasm characterized by the absence of malignant morphological characteristics and metastases. this category includes melanocytic nevus, benign epithelial melanosis of the conjunctiva, and wnt-activated deep penetrating/plexiform melanocytoma (nevus).

a melanocytic neoplasm that arises from the conjunctiva. this category includes conjunctival nevi, conjunctival melanocytic intraepithelial lesions, and conjunctival melanomas.

a neoplasm that arises from melanocytes in the skin. this category includes nevi, melanocytomas, and melanomas.

a melanocytic neoplasm that arises from the eyelid. this category includes nevi and melanomas.

a cutaneous neoplasm associated with mitf gene rearrangement and either actin-mitf translocation or mitf-crem translocation. it is composed of large cells with clear cytoplasm that exhibit melanocytic differentiation and proliferate in the dermis. it presents as a single non-pigmented cutaneous nodule.

a melanocytic neoplasm that arises from the iris, ciliary body, and choroid. this category includes nevi, melanocytomas, and melanomas.

a rare, immune-mediated disorder characterized by cerebellar degeneration due to the presence of an often undetected malignancy (usually carcinoma or lymphoma) in an anatomic site other than the cerebellum. signs and symptoms include progressive ataxia, dysarthria, and nystagmus.

a rare disorder characterized by degenerative changes in the limbic area of the brain. causes include infections and autoimmune conditions; it may also manifest as a paraneoplastic syndrome, most often caused by small cell lung carcinoma. signs and symptoms include behavioral changes, hallucinations and dementia.

a primary meningeal melanocytic neoplasm that occurs in adults.

a group of cutaneous melanocytic neoplasms that includes the combined bap1-inactivated nevus and the bap1-inactivated melanocytoma.

a primary tumor of the central nervous system that arises from leptomeningeal melanocytes. it may present as a diffuse proliferative leptomeningeal process (often as a component of the neurocutaneous melanosis complex) or as a distinct mass lesion.

a circumscribed neoplasm that arises from leptomeningeal melanocytes. this category includes meningeal melanocytoma, meningeal melanoma, and meningeal melanocytoma of intermediate grade.

a melanocytic neoplasm that arises from the skin or mucosal sites in the head and neck region.

a rare variant of malignant peripheral nerve sheath tumor. it is characterized by the presence of malignant cells that contain melanin.

a benign or malignant, primary or metastatic neoplasm affecting the melanocytes.

a benign, intermediate, or malignant circumscribed or diffuse neoplasm that arises from melanocytes in the leptomeninges. it includes meningeal melanocytoma, meningeal melanoma, meningeal melanocytoma of intermediate grade, and meningeal melanocytosis.

a neoplasm that arises from melanocytes in the skin.

a neoplasm that originates from melanocytes and arises from the vulva. this category includes congenital and acquired melanocytic nevus, blue nevus, dysplastic melanocytic nevus, atypical melanocytic nevus, genital type, and melanoma.

a melanocytic neoplasm that arises from the leptomeninges and occurs during adulthood.

a cutaneous melanocytoma caused by the inactivation of bap1 tumor suppressor gene. it is characterized by the presence of a predominantly intradermal proliferation of large epithelioid melanocytes with a large amount of eosinophilic cytoplasm, and vesicular nuclei with prominent nucleoli. progression to melanoma is infrequent.

a melanocytic neoplasm that arises from the leptomeninges. this category includes diffuse proliferative processes (melanocytosis and melanomatosis) and circumscribed processes (melanocytoma and melanoma).

a benign, atypical, or malignant neoplasm that arises from and is composed of melanocytes and occurs during childhood.

a circumscribed neoplasm that arises from leptomeningeal melanocytes. this category includes meningeal melanocytoma and meningeal melanoma.

a melanocytic neoplasm that arises from the conjunctiva. this category includes conjunctival nevus, conjunctival melanocytic intraepithelial lesions, and conjunctival melanoma.

a diffuse proliferation of melanocytes that affects the leptomeninges. this category includes melanocytosis and melanomatosis.

a benign, atypical, or malignant neoplasm that arises from and is composed of melanocytes. this category includes melanocytic nevi, melanocytomas, and melanomas.

a cutaneous neoplasm associated with mitf gene rearrangement and either actin-mitf translocation or mitf-crem translocation. it is composed of large cells with clear cytoplasm that exhibit melanocytic differentiation and proliferate in the dermis. it presents as a single non-pigmented cutaneous nodule.

a neoplasm that arises from melanocytes in the skin. this category includes nevi, melanocytomas, and melanomas.

a melanocytic neoplasm that arises from the iris, ciliary body, and choroid. this category includes nevus and its subtype melanocytoma, and melanoma.

a neoplasm that originates from melanocytes and arises from the vulva. this category includes congenital and acquired melanocytic nevus, blue nevus, dysplastic melanocytic nevus, atypical melanocytic nevus of genital type, and melanoma.

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

References found for this diagnosis code in the External Cause of Injuries Index:

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

ICD-9-CM: 239.9

This is a direct match with no additional mapping qualifiers. The absence of a flag generally means the mapping is considered exact or precise. In other words, the ICD-10 code maps cleanly to the ICD-9 code without qualification, approximation, or needing multiple codes.

This code is referenced in the table of neoplasms by anatomical site. For each site there are six possible code numbers according to whether the neoplasm in question is malignant, benign, in situ, of uncertain behavior, or of unspecified nature. The description of the neoplasm will often indicate which of the six columns is appropriate.

Where such descriptors are not present, the remainder of the Index should be consulted where guidance is given to the appropriate column for each morphological (histological) variety listed. However, the guidance in the Index can be overridden if one of the descriptors mentioned above is present.

Filter table of neoplasms:

Neoplasm, neoplastic Malignant Primary Malignant Secondary CaInSitu Benign Uncertain Behavior Unspecified Behavior
»Neoplasm, neoplastic »unknown site or unspecified C80.1 C79.9 D09.9 D36.9 D48.9 D49.9