Medical Staffing Network Holdings Inc. (OTCBB: MNSW.PK), one of the largest healthcare staffing firms, said it's continuing discussions with lenders over a default, but said it could file for bankruptcy protection, according to a filing with the U.S. Securities and Exchange Commission on Tuesday.

"The company believes that based on currently projected cash inflows generated from operations, it is possible that the company  may be unable to pay future scheduled interest and principal payments due to its senior lenders as such obligations become due," according to the filing.

The company's lenders have a lien on most of its assets and could sell those assets under the terms of the credit agreements, according to the Medical Staffing Network Holdings. And the company could file for Chapter 11 bankruptcy, or Chapter 7 bankruptcy, if lenders take such actions, the filing said.

Medical Staffing Network Holdings also said its first lien lenders are no longer allowing the company to borrow under a portion of the credit agreement. "As a result, the company's financial condition and business would be adversely affected if the company were to need liquidity assistance to fund its obligations as they come due," according to the filing.

Boca Raton FL-based Medical Staffing Network Holdings ranked No. 4 on Staffing Industry Analysts' list of largest healthcare staffing firms. It also operates a vendor management system.