Dermatology Coding Alert

A 5th digit on this insurance 'front-gate' diagnosis will prevent kick-outs.

Although your Merkel cell cancer and unspecified nature neoplasm coding familiarity is under attack from added ICD-9 specificity, you can protect your practice from incorrect entries by following these rules.

ICD-9 2010 brings you specific options for Merkel cell carcinoma (CA) including 209.31 (Merkel cell carcinoma of the face), 209.32 (... of the scalp and neck), and 209.36 (... of other sites). Using ICD-9 2009 codes, you have to lump this cancer under 173.x (Other malignant neoplasm of skin), which are mainly for basal cell and squamous cell cancers.

"Separating out the Merkel cell type is a step in the right direction, in regards to further delineation of the types of cancer and ICD-9 coding to a specific type," says Andrew Borden, CCS-P, CPC, reimbursement manager at the Medical College of Wisconsin in Milwaukee. "Merkel cell diagnoses will allow more detailed description for this fast-growing cancer which occurs within the skin layer(s) but not on the surface."

Merkel cell carcinoma has roughly 1,500 new cases each year -- and that number is on the rise. The new codes should help identify and track patients, according to an ICD-9-CM committee meeting diagnosis agenda (www.cdc.gov/nchs/data/icd9/agendaSep08.pdf).

If your dermatologist's treating Merkel cell cancer that has metastasized, you're going to have to look outside category 209.3x (Malignant poorly differentiated neuroendocrine tumors). Code 209.30 (Malignant poorly differentiated neuroendocrine carcinoma, any site) is not appropriate for secondary Merkel cell carcinoma. You'll instead turn to 209.75 (Secondary Merkel cell carcinoma).

Key words: The ICD-9-CM Alphabetic Index points you to 209.75 for several

Merkel cell cancer terms, including:

• nodal presentation

• secondary Merkel cell, any site

• unknown primary site.

When insurers require ICD-9 2010 codes to indicate a lesion's location prior to pathology, 239.8 (Neoplasms of unspecified nature; other specified sites) will require a fifth digit of "9" (... other specified sites) or 1 (... retina and choroid). "Unspecified nature codes are used quite often, since they are the 'front gate' for when no diagnosis has yet been determined," Borden points out.

You don't need histologic confirmation to report these "unspecified nature" codes, according to the "ICD-9-CM Coordination and Maintenance Committee Meeting March 19-20, 2008, Diagnosis genda" (www.cdc.gov/nchs/data/icd9/agendaMa08.pdf). In contrast, "unspecified behavior" codes require histologic confirmation.

Beware: You shouldn't "flip to this section of the Neoplasm Table and report an 'unspecified nature' code. The ICD-9-CM Alphabetic Index will point to this code based on the patient's condition," explains Cindy Parman, CPC, CPC-H, RCC, principal with Coding Strategies Inc. in Powder Springs, Ga.

Surprise: And dermatology coders will be directed there quite often. "Code 239.2 has been the 'catch-all' code for skin, bone and soft tissue for a long time," Borden says.

When ICD-9 2009 deletes 239.8, you'll instead use 239.89 for the following "other specified sites":

• cheek

• ear, inner and middle

• face NEC

• head NEC

• jaw

• nasolacrimal duct

• neck NEC

• nose, nasal

• peritonsillar (tissue).