C90.20

HCC Category Mapping

What This Code Means

Extramedullary plasmacytoma, a tumor of plasma cells that occurs outside the bone marrow, that has not responded to treatment.

Coding Tips

• •Extramedullary plasmacytoma occurs in soft tissues outside bone marrow; verify location is documented
• •Fifth character '0' indicates no remission; document the site of the tumor for complete coding

Clinical Significance

Extramedullary plasmacytoma is a solitary tumor of neoplastic plasma cells occurring outside the bone marrow, most commonly in the upper respiratory tract including the nasopharynx, paranasal sinuses, and oropharynx. Unlike multiple myeloma, it is typically a localized disease amenable to radiation therapy. Non-remission status indicates the tumor persists or has progressed despite treatment.

Documentation Requirements

• ✓Documentation must include tissue biopsy confirming a monoclonal plasma cell tumor outside the bone marrow.
• ✓The specific extramedullary site must be documented.
• ✓Imaging confirming absence of additional lesions, bone marrow biopsy excluding myeloma, serum and urine protein studies, treatment approach (typically radiation), and non-remission status are required.

Commonly Confused Codes