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Official Description

Biopsy, soft tissue of back or flank; deep

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

Soft tissue biopsy of the back or flank involves the extraction of a tissue sample from deeper layers of the skin and underlying structures. The term "soft tissue" encompasses various components, including muscles, tendons, fat, blood vessels, lymph vessels, nerves, and the tissues surrounding joints. This procedure is typically performed when there is a need to investigate a mass or lesion that may be present in these areas. Depending on the specific site and depth of the biopsy, the patient may receive local, regional, or general anesthesia, or conscious sedation to ensure comfort during the procedure. Prior to the biopsy, the skin over the targeted area is thoroughly cleansed to minimize the risk of infection. A surgical incision is then made, allowing the physician to carefully dissect through the layers of tissue down to the mass or lesion while taking precautions to avoid damaging any nearby blood vessels or nerves. Once the tissue sample is obtained, it is sent to a laboratory for histological evaluation, which is reported separately. After the sample is collected, the incision is closed using sutures to promote proper healing. It is important to note that for superficial biopsies, a different code, 21920, should be used, while 21925 is specifically designated for deeper tissue biopsies that require more extensive dissection of the overlying tissues.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

Soft tissue biopsy of the back or flank is indicated for various clinical scenarios where further investigation of a mass or lesion is necessary. The following conditions may warrant this procedure:

  • Suspicious Mass or Lesion A palpable mass or lesion in the back or flank that requires histological examination to determine its nature, whether benign or malignant.
  • Unexplained Pain or Symptoms Persistent pain or other unexplained symptoms in the back or flank region that may be associated with underlying soft tissue abnormalities.
  • Monitoring of Known Conditions Biopsy may be indicated for patients with known conditions that could lead to changes in soft tissue, such as sarcoma or other tumors.

2. Procedure

The procedure for a soft tissue biopsy of the back or flank involves several critical steps to ensure the safe and effective collection of tissue samples.

  • Preparation The patient is positioned comfortably, and the area over the planned biopsy site is cleansed with an antiseptic solution to reduce the risk of infection. Depending on the depth and location of the biopsy, appropriate anesthesia is administered to ensure patient comfort during the procedure.
  • Incision and Dissection A surgical incision is made over the targeted area, allowing the physician to carefully dissect through the layers of soft tissue. This dissection is performed with precision to reach the mass or lesion while protecting surrounding blood vessels and nerves from injury.
  • Tissue Sample Collection Once the mass or lesion is accessed, a tissue sample is obtained. This sample is critical for histological evaluation, which will provide essential information regarding the nature of the tissue.
  • Closure After the tissue sample is collected, the incision is closed using sutures. Proper closure is vital to promote healing and minimize scarring.

3. Post-Procedure

Post-procedure care for a soft tissue biopsy of the back or flank includes monitoring the biopsy site for any signs of infection, such as increased redness, swelling, or discharge. Patients are typically advised to keep the area clean and dry and to follow any specific instructions provided by the healthcare provider regarding wound care. Pain management may be necessary, and over-the-counter analgesics can be recommended. Patients should also be informed about the expected timeline for receiving histological results and any follow-up appointments that may be required to discuss the findings and further management options.

Short Descr BIOPSY SOFT TISSUE OF BACK
Medium Descr BIOPSY SOFT TISSUE BACK/FLANK DEEP
Long Descr Biopsy, soft tissue of back or flank; deep
Status Code Active Code
Global Days 090 - Major Surgery
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 1 - Statutory payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Hospital Part B services paid through a comprehensive APC
ASC Payment Indicator Surgical procedure on ASC list in CY 2007; payment based on OPPS relative payment weight.
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P6B - Minor procedures - musculoskeletal
MUE 2
CCS Clinical Classification 159 - Other diagnostic procedures on musculoskeletal system
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
78 Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.)
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
AS Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery
GC This service has been performed in part by a resident under the direction of a teaching physician
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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