C31.3
BillableMalignant neoplasm of sphenoid sinus
HCC Category Mapping
V28HCC 21 — Breast, Prostate, Colorectal and Other Cancers and Tumors
0.545V24HCC 11 — Colorectal, Bladder, and Other Cancers
0.306ESRDHCC 11 — Colorectal, Bladder, and Other Cancers
0.000RxHCCHCC 22 — Cancer, Other Specified Sites
0.000What This Code Means
Cancer that develops in the sphenoid sinus, an air-filled cavity deep in the skull behind the nose.
Coding Tips
- •Sphenoid sinus cancer is rare and often diagnosed late due to deep location
- •Document proximity to critical structures including the pituitary gland and cavernous sinus
Clinical Significance
Sphenoid sinus cancer is rare and extremely dangerous due to the sinus's deep skull base location adjacent to the pituitary gland, cavernous sinus, optic nerves, and internal carotid arteries. These tumors typically present at advanced stages because early symptoms are minimal. Surgical access is challenging, often requiring endoscopic skull base approaches.
Documentation Requirements
- ✓Pathology confirmation with histological type
- ✓MRI and CT imaging confirming sphenoid sinus as primary site
- ✓Assessment of invasion into adjacent critical structures (cavernous sinus, optic nerves, pituitary, carotid arteries)
- ✓TNM staging and treatment plan
- ✓Endocrine evaluation if pituitary involvement is suspected
Commonly Confused Codes
C75.1 — Malignant neoplasm of pituitary gland: Sphenoid sinus tumors can invade the pituitary; confirm the primary originC31.1 — Ethmoidal sinus: Adjacent sinus; ensure imaging confirms sphenoid originD35.2 — Benign neoplasm of pituitary gland: Pituitary adenomas can extend into the sphenoid but are benignC31.9 — Accessory sinus, unspecified: Do not default to unspecified when sphenoid is documented