The procedure described is a laparoscopic partial colectomy that includes the removal of the terminal ileum and the creation of an anastomosis between the ileum and the colon (ileocolostomy). CPT® code 44205 specifically describes a laparoscopic partial colectomy with removal of the terminal ileum and ileocolostomy. The diagnosis is adenocarcinoma of the "proximal colon." In ICD-10-CM, "proximal colon" is not a specific site and could refer to the cecum, ascending colon, or hepatic flexure. Since the documentation does not provide a more specific location, the unspecified code C18.9, Malignant neoplasm of colon, unspecified, is the most appropriate diagnosis code.

A. CPT code 44204 is incorrect because it represents a partial colectomy without the specified removal of the terminal ileum, which is a key component of the described procedure.

B. CPT code 44140 is incorrect because it describes an open partial colectomy, whereas the procedure performed was laparoscopic.

D. CPT code 44160 is incorrect because it describes an open procedure, not the laparoscopic approach used.

1. American Medical Association. (2023). CPT® 2024 Professional Edition.

Page 383: The descriptor for CPT code 44205 is "Laparoscopy

surgical; colectomy

partial

with removal of terminal ileum with ileocolostomy." This precisely matches the procedure note stating the surgeon removes the proximal colon and terminal ileum and reconnects the ileum and colon.

Page 383: The descriptor for CPT code 44204

"Laparoscopy

surgical; colectomy

partial

with anastomosis

" does not include the removal of the terminal ileum

making it less specific and therefore incorrect.

Pages 381-382: Codes 44140 and 44160 are listed under the "Excision" heading for open procedures of the intestines

confirming they are incorrect for a laparoscopic approach.

2. Centers for Disease Control and Prevention. (2023). ICD-10-CM Official Guidelines for Coding and Reporting FY 2024.

Section I.B.2

Level of Detail in Coding: "Diagnosis codes are to be used and reported at their highest number of characters available. A three-character code is to be used only if it is not further subdivided."

Section I.B.5

Use of Sign/Symptom/Unspecified Codes: "If a definitive diagnosis has not been established by the end of the encounter

it is appropriate to report codes for signs and/or symptoms in lieu of a definitive diagnosis. When sufficient clinical information isn’t known or available about a particular health condition to assign a more specific code

it is acceptable to report the appropriate 'unspecified' code (e.g.

a diagnosis of pneumonia has been determined

but not the specific type)." In this case

"proximal colon" is not specific enough to select C18.0

C18.2

or C18.3

making C18.9 the correct choice.