Editorial orientation provided by MedAPI — not part of the coding instruction.
C11 encompasses primary malignant neoplasms arising in the nasopharynx, including the superior, posterior, lateral, and anterior walls. The lateral wall includes the pharyngeal recess (fossa of Rosenmüller), a common site of origin.
Common Histologies
- Nonkeratinizing squamous cell carcinoma, often associated with Epstein–Barr virus (EBV)
- Keratinizing squamous cell carcinoma, more strongly associated with tobacco exposure
- Basaloid squamous cell carcinoma, which is uncommon
Other malignancies can arise in this region, but histology must be established pathologically.
Common Symptoms
- Painless cervical lymphadenopathy, sometimes the initial presentation (R59.0)
- Persistent unilateral nasal obstruction (R09.89), congestion (R09.81), or epistaxis (R04.0)
- Unilateral middle-ear effusion (H65.90), hearing loss (H90.2), tinnitus (H93.11), or ear pressure (H69.92)
- Headache (R51.9), facial pain (G50.1), diplopia (H53.2), or cranial neuropathies with skull-base involvement (G52.7)
- Trismus or other symptoms of locally advanced disease (R68.84)
Persistent unilateral otologic symptoms in an adult warrant evaluation of the nasopharynx.
Diagnosis
Evaluation generally includes nasopharyngoscopy with biopsy. MRI is preferred for defining the primary tumor, skull base, intracranial extension, and perineural spread; contrast-enhanced CT may supplement assessment of bone and cervical nodes. PET/CT or other systemic imaging may be used to evaluate nodal and distant disease.
Pathologic examination should distinguish nasopharyngeal carcinoma from lymphoma, salivary-type tumors, mucosal melanoma, and metastatic disease involving the nasopharynx.
Staging
Nasopharyngeal carcinoma is staged using site-specific TNM criteria based on local extension, cervical and retropharyngeal nodal disease, and distant metastasis. Cervical nodal involvement is common at diagnosis. Important local extensions include the parapharyngeal space, skull base, cranial nerves, orbit, hypopharynx, and intracranial structures.
Molecular Markers
EBV-encoded RNA in situ hybridization is commonly used to support the diagnosis of EBV-associated nonkeratinizing carcinoma. Plasma EBV DNA may assist with prognosis, treatment monitoring, and surveillance in appropriate settings. Unlike many oropharyngeal cancers, p16 immunoreactivity alone is not a reliable surrogate for HPV-driven nasopharyngeal carcinoma.
Common Treatments
Radiation therapy is central because of the anatomic location and radiosensitivity of many nasopharyngeal carcinomas. Depending on stage, treatment may include:
- Definitive intensity-modulated radiation therapy for selected early-stage disease
- Concurrent platinum-based chemoradiation for locoregionally advanced disease
- Induction chemotherapy followed by chemoradiation in selected higher-risk cases
- Systemic therapy, including immunotherapy in appropriate patients, for recurrent or metastatic disease
- Salvage surgery or re-irradiation for carefully selected localized recurrences
Treatment planning should address the primary site, retropharyngeal and cervical nodal regions, and potential late effects involving hearing, swallowing, salivary function, endocrine function, and cranial nerves.
Scope Note
C11 identifies the anatomic site of a primary malignant neoplasm of the nasopharynx, with child codes specifying the involved wall, overlapping sites, or an unspecified nasopharyngeal site. It does not encode histologic subtype, EBV or HPV status, grade, TNM stage, nodal status, treatment response, or recurrence. Secondary malignant involvement of the nasopharynx or distant metastatic disease is not classified as a primary C11 neoplasm. Tobacco or environmental smoke exposure, when documented and relevant, is represented separately.