09-05-2025
Scenario:
- Laryngoscopy: Base of tongue mass occupied the majority of the midline base of tongue
- Path: Biopsy Base of tongue lesion: biopsy Polymorphous adenocarcinoma, cribriform subtype, of salivary gland origin
- Op Note:
- PREOPERATIVE DIAGNOSIS: Polymorphous adenocarcinoma of the left tongue base with bilateral regional metastasis
- POSTOPERATIVE DIAGNOSIS: Same
- OPERATIONS: Composite resection of left tongue base mass and left neck dissection with mandibulotomy, tracheostomy
- Path:
- Final Dx: Soft tissue, left tongue base resection, excision/resection: Polymorphous adenocarcinoma, cribriform subtype, of minor salivary gland origin, 1.4 cm in greatest dimension
- Synoptic
- Tumor Site: Oropharynx
- Tumor Subsite: Base of tongue
- Tumor Laterality: Left
- Tumor Size: Greatest Dimension (Centimeters): 1.4 cm
- Histologic Type: Polymorphous adenocarcinoma, cribriform subtype
Question: How would you assign primary site?
- C01.9 Base of Tongue
- C10.9 Oropharynx
- C06.9 Minor Salivary Gland, NOS
Answer & Discussion: C01.9 Base of Tongue
You might be tempted to try and code this primary site as minor salivary gland due to the path report stating the tumor is Polymorphous adenocarcinoma, cribriform subtype, of minor salivary gland origin, but that is not correct.
Refer to ICD0-3 manual, 4.3.5 Site-associated morphology terms, the section on the Pseudo Topographic morphology terms page 24. The key takeaways from that section of the manual:
- The term “minor salivary gland” should be ignored in a diagnosis such as “minor salivary gland adenoid cystic carcinoma,” code to the primary site of origin
- C06.9 is used only when the site is not specified
