ICD-10 Diagnosis Code C78.6

Secondary malignant neoplasm of retroperiton and peritoneum

Diagnosis Code C78.6

ICD-10: C78.6
Short Description: Secondary malignant neoplasm of retroperiton and peritoneum
Long Description: Secondary malignant neoplasm of retroperitoneum and peritoneum
This is the 2019 version of the ICD-10-CM diagnosis code C78.6

Valid for Submission
The code C78.6 is valid for submission for HIPAA-covered transactions.

Code Classification
  • Neoplasms (C00–D48)
    • Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)
      • Secondary malignant neoplasm of resp and digestive organs (C78)
Version 2019 Billable Code Neoplasm Malignant Secondary

Information for Medical Professionals

Diagnostic Related Groups
The diagnosis code C78.6 is grouped in the following Diagnostic Related Group(s) (MS-DRG V35.0)


Convert to ICD-9
  • 197.6 - Sec mal neo peritoneum

  • Carcinomatosis of peritoneal cavity
  • Gallbladder TNM finding
  • Invasion of neoplasm to visceral peritoneum
  • Malignant neoplasm of mesentery
  • Malignant neoplasm of omentum
  • Malignant neoplasm of perinephric tissue
  • Malignant tumor of peritoneum and retroperitoneum
  • Metastasis to peritoneum of unknown primary
  • Metastasis to retroperitoneum of unknown primary
  • Neoplasm of omentum
  • Neoplasm of parietal peritoneum
  • Neoplasm of periadrenal tissue
  • Neoplasm of rectouterine pouch
  • Neoplasm of retrocecal tissue
  • Neoplasm of the mesocolon
  • Pseudomyxoma peritonei
  • pT3
  • pT3 and/or N1
  • pT3 and/or N1
  • pT3: Tumor penetrates serosa
  • pT3: Tumor perforates the serosa
  • pT3a
  • pT3a
  • pT3b
  • pT3b
  • pT3c
  • pT3c AND/OR N1
  • pT3c and/or N1
  • pT3c category
  • pT4: Tumor directly invades other organs or structures and/or perforates visceral peritoneum
  • Renal tumor invasion into perinephric tissue macroscopically
  • Secondary malignant neoplasm of adrenal gland
  • Secondary malignant neoplasm of omentum
  • Secondary malignant neoplasm of parietal peritoneum
  • Secondary malignant neoplasm of pelvic peritoneum
  • Secondary malignant neoplasm of periadrenal tissue
  • Secondary malignant neoplasm of perirenal tissue
  • Secondary malignant neoplasm of peritoneum
  • Secondary malignant neoplasm of rectouterine pouch
  • Secondary malignant neoplasm of retrocecal tissue
  • Secondary malignant neoplasm of retroperitoneum
  • Secondary malignant neoplasm of retroperitoneum and peritoneum
  • Secondary malignant neoplasm of the mesentery
  • Secondary malignant neoplasm of the mesocolon
  • T3 and/or N1 with peritoneal implants outside the pelvis and/or regional lymph node metastasis
  • T3 and/or N1 : Ovarian tumor involves one or both ovaries with microscopically confirmed peritoneal metastasis outside the pelvis and/or regional lymph node metastasis
  • T3: Renal tumor extends into major veins or invades the adrenal gland or perinephric tissues but not beyond Gerota's fascia
  • T3a : Fallopian tube/ovarian tumor with microscopic peritoneal metastasis beyond pelvis
  • T3a: Renal tumor invades the adrenal gland or perinephric tissues but not beyond Gerota's fascia
  • T3b : Fallopian tube/ovarian tumor with macroscopic peritoneal metastasis beyond pelvis < 2 cm in greatest dimension
  • T3c : Fallopian tube/ovarian tumor with peritoneal metastasis beyond pelvis > 2 cm in greatest dimension and/or regional lymph node metastasis
  • T4: Pleural tumor directly extends to any of the following: contralateral pleura, contralateral lung, peritoneum, intra-abdominal organs, cervical tissues
  • T4b: Colon/rectum tumor penetrates the visceral peritoneum
  • Tumor invades retroperitoneal structure
  • Tumor of peritoneum and retroperitoneum

Index to Diseases and Injuries
References found for the code C78.6 in the Index to Diseases and Injuries:

Table of Neoplasms

The code C78.6 is included 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.

The Tabular must be reviewed for the complete diagnosis code.

Neoplasm, neoplastic Malignant
CaInSitu Benign Uncertain
»connective tissue NEC
»cul-de-sac (Douglas')
»Douglas' cul-de-sac or pouch
»mesentery, mesenteric
»periadrenal (tissue)
»perirenal (tissue)
»peritoneum, peritoneal (cavity)
»peritoneum, peritoneal (cavity)
»peritoneum, peritoneal (cavity)
»peritoneum, peritoneal (cavity)
  »specified part NEC
»rectouterine pouch
»retroperitoneal (space) (tissue)

Information for Patients


Also called: Carcinoma, Malignancy, Neoplasms, Tumor

Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor. Tumors can be benign or malignant. Benign tumors aren't cancer while malignant ones are. Cells from malignant tumors can invade nearby tissues. They can also break away and spread to other parts of the body.

Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for where they start. For example, lung cancer starts in the lung, and breast cancer starts in the breast. The spread of cancer from one part of the body to another is called metastasis. Symptoms and treatment depend on the cancer type and how advanced it is. Most treatment plans may include surgery, radiation and/or chemotherapy. Some may involve hormone therapy, immunotherapy or other types of biologic therapy, or stem cell transplantation.

NIH: National Cancer Institute

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Peritoneal Disorders

Your peritoneum is the tissue that lines your abdominal wall and covers most of the organs in your abdomen. A liquid, peritoneal fluid, lubricates the surface of this tissue.

Disorders of the peritoneum are not common. They include

  • Peritonitis - an inflammation of the peritoneum
  • Cancer
  • Complications from peritoneal dialysis

Your doctor may use imaging tests or lab tests to analyze the peritoneal fluid to diagnose the problem. Treatment of peritoneal disorders depends on the cause.

  • Peritonitis (Medical Encyclopedia)
  • Peritonitis - secondary (Medical Encyclopedia)
  • Peritonitis - spontaneous bacterial (Medical Encyclopedia)
  • Retroperitoneal inflammation (Medical Encyclopedia)

[Read More]

ICD-10 Footnotes

General Equivalence Map Definitions
The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.

  • Approximate Flag - The approximate flag is on, indicating that the relationship between the code in the source system and the code in the target system is an approximate equivalent.
  • No Map Flag - The no map flag indicates that a code in the source system is not linked to any code in the target system.
  • Combination Flag - The combination flag indicates that more than one code in the target system is required to satisfy the full equivalent meaning of a code in the source system.

Present on Admission
The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement.

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