Pathology/Lab Coding Alert

CPT 2000 does not contain a specific procedural code for sentinel lymph node biopsy. That may mean some practices are not capturing the full reimbursement they are entitled to for the steps involved in the procedure.

Sentinel lymph node biopsy is a fairly new procedure used to detect the spread of breast cancer or melanoma (skin cancer) to the lymph nodes, says Matthew McCoy, MD, pathologist at Methodist Hospital, a part of HealthSystem Minnesota in St. Louis Park, Minn. Because its new, we have to use existing procedural codes to describe the separate steps of the procedure and simply add them up.

The sentinel node is the first draining node of a regional lymph node basin. The theory behind sentinel lymph node biopsy is that the sentinel node is the first place cancer cells would lodge if they were traveling through the lymphatic system. Therefore, if the sentinel node contains no metastases, then neither will the remaining nodes in that basin. This procedure can give direction regarding the advisability of treatment options, such as complete node dissection, radiation therapy, and chemotherapy, states McCoy.

Sentinel node biopsy can entail more careful study for occult metastases because it involves one or a few nodes, as opposed to 20 or 30 from a regional resection, continues McCoy. The nodes can be examined using serial sectioning or histochemical staining techniques to identify micrometastases, which have been associated with recurrence of the disease. This type of in-depth histologic examination is not feasible for all nodes involved in a regional resection.

Breast Cancer: A Clinical Example

A patient presenting with a suspected neoplasm of the breast, ICD9 239.3 (breast neoplasm of unspecified nature), first would undergo a diagnostic test to determine the nature of the lump. This might be done using fine needle aspiration (FNA), which is coded 88170 for superficial lesions, or 88171 for deep tissue lesions aspirated under radiologic guidance. The pathologist reports codes 88172 (evaluation of fine needle aspirate with or without preparation of smears; immediate cytohistologic study to determine adequacy of specimen[s]) and 88173 ( interpretation and report) if these services are provided.

More often, we use a radiologically guided Tru-Cut core biopsy for diagnostic purposes, reports McCoy. The surgical procedure is reported using code 19100 (biopsy of breast; needle core) and the radiological supervision with code 76095 (stereotactic localization for breast biopsy). The pathologists gross and microscopic evaluation of the core-needle biopsy is coded 88305 (breast, biopsy, not requiring microscopic evaluation of surgical margins). If the biopsy reveals a malignant neoplasm of the breast [174.x], the patient is scheduled for surgery at a later date.

The sentinel lymph node biopsy is conducted at the time of surgery. According to McCoy, The first step is to inject the site of the cancer with a radioisotope called technetium 99. This preoperative lymphoscintigraphy allows the radiologist to assess lymphatic drainage. The now-radioactive sentinel node is identified using a hand-held gamma detector, and the location marked for the surgeon. The code for this procedure is 78195 (lymphatics and lymph glands imaging).

The cancer site is then injected with isosulfan blue dye to further assist the surgeon in locating the sentinel node, says McCoy. Code 38792 (injection procedure; for identification of sentinel node) is used to report this service. The biopsy or excision of the sentinel node(s) most commonly involved in breast cancer is reported using the appropriate code, based on the location of the node. These are 38500 (superficial), 38525 (deep axillary node[s]) or 38530 (internal mammary node[s]).

The pathologist receives the sentinel node and carries out the gross and microscopic examination involved in a lymph node biopsy, which is coded 88305, states McCoy. We also examine frozen sections and consult with the surgeon on the results of our findings, which is coded 88331 (pathology consultation during surgery; with frozen section[s], single specimen). If the result of the sentinel node biopsy is positive at this point, the pathologist advises the surgeon of these findings.

More often than not, in this situation the surgeon will proceed with an axillary dissection during the same surgical session. The tumor also is removed at the same time. The tissue is submitted to the pathologist for examination, and is coded 88309 (breast, mastectomywith regional lymph nodes). If, however, the sentinel node is negative, based on the initial examination and frozen sections, the surgeon will likely proceed with a lumpectomy and leave the axillary lymph nodes intact, says McCoy. The pathologists examination of the excised tissue is coded 88307 (breast, mastectomypartial/simple).

Detection of Occult Microscopic Metastases

At this point, the pathologists arent done with the sentinel node, says McCoy. They carry out more extensive serial sectioning and histochemical staining to look for occult, microscopic metastases.

Lena Spencer, MA, HTL (ASCP), HT, QIHC, histotechnologist at Norton Healthcare, a hospital in Louisville, Ky., concurs. We may have six to eight paraffin blocks prepared from the sentinel node specimen, she says. For each block, we cut serial sections and pull off five slides at predetermined intervals for H and E [hematoxylin/eosin] staining. According to the information weve received, the multiple blocks and slides are not reportable separately but are bundled with the original 88305 [lymph node biopsy] service. This interpretation is aligned with CPT direction for surgical pathology (the unit of service for codes 88300 through 88309 is the specimen, defined as tissue or tissues requiring individual examination and pathologic diagnosis).

Spencer continues, From the same serial sectioning of each block, we pull two slides at predetermined intervals for histochemical staining with cytokeratin. For the keratin, we code 88342 (immunocytochemistry [including tissue immunoperoxidase], each antibody) one time, even if we have two slides per block by six or eight blocks. Again, because the specimen is the unit of service, 88342 should not be coded separately for each slide, only for each antibody. This distinction is clarified in CPT Assistant Winter 91:18, which states, Each antibody used in an immunocytochemistry study of a specimen [emphasis added] should be separately coded as 88342.

Sentinel Lymph Node Biopsy Is a Separate Procedure

Lacking a specific code that captures the pathologists work involved in sentinel lymph node biopsy, coders are left to report the various steps involved in the process. Although lymph nodes often are considered bundled with the larger surgical specimen (e.g., 88309, breast, mastectomywith regional lymph nodes), in this case it is considered a separate specimen. McCoy and Spencer agree that the sentinel lymph node biopsy is coded separately as 88305 (lymph node, biopsy). Interpreting the frozen sections and consulting with the surgeon regarding the results of the biopsy is coded 88331, says McCoy. And the histochemical staining of the lymph node sections is coded 88342, concludes Spencer.