What is metastatic squamous cell carcinoma of unknown primary?
- metastatic disease in the cervical lymphatics without evidence of a primary mucosal or soft tissue tumor.
- diagnosis of exclusion
How does metastatic squamous cell carcinoma present in the neck?
- as a painLESS neck mass
- half present with a single lymph node
With what is metastatic squamous cell carcinoma of the neck associated?
- HPV (16 and 18) in the oropharynx
When are most primary tumors of metastatic SCC of the neck identified?
at autopsy bc they are often so small
What lymphatics are most commonly involved in metastatic SCC of the neck?
- level II cervical lymphatics
What does level III cervical lymphatic involvement mean with metastatic SCC?
- a primary lesion in the supraglottic larynx or hypopharynx (midneck)
What does level IV cervical lymphatic involvement in the absence of disease in other levels suggest with metastatic SCC?
- infraclavicular primary tumor
What are the neck levels?
- 1A= midline and anterior belly of digastric muscle.
- 1B= submandibular region
- 2A= mandible and posterior digastric muscle, down to level of hyoid bone.
- 2B= mastoid tip to anterior and posterior borders of SCM (OROPHARYNX).
- 3= hyoid superiorly and anterior and posterior borders of SCM and inferiorly to cricoid cartilage (MIDNECK).
- 4= cricoid cartilage down to clavicular head (SUPRACLAVICULAR FOSSA).
- 5= mastoid tip, posterior border of SCM, anterior border of trapezius and down to clavicle (5A and 5B divided by cricoid cartilage).
- 6= pretracheal nodes
- 7= superior mediastinal nodes (THYROID CANCERS).
** What is the first step in obtaining tissue in the diagnosis of any neck mass?
- Fine needle aspiration (FNA).
* if non-diagnostic, it should be repeated with image guidance.
Should an open biopsy be used to diagnose a neck mass?
NO because tumor spillage may occur leading to tumor spread due to disruption of fascial planes.
*However, if you need to, have a head and neck surgeon perform it.
Where should directed biopsies be performed?
- on all areas of mucosal irregularity, bleeding or friability, or areas of concern identified on imaging.
What is often performed in addition to directed biopsies?
- bilateral tonsillectomy +/- lingual tonsillectomy
What has improved rates of success in identifying an occult primary tumor located in the tonsils or tongue base (lingual tonsils)?
- transoral robotic surgery (TORS)
What else has emerged as a useful imaging modality in identifying occult primary tumors?
- PET CT
How does PET CT identify tumors?
- it uses radioactive fluoro-2-deoxy-glucose (FDG) to identify metabolically hyperactive cells. Malignant cells have a higher rate of glucose uptake so these will light up.
- must do this prior to panendoscopy (biopsy) to avoid false-positives.
Does a negative PET preclude the need for EUA with biopsies?
NO, you must still do the EUA with biopsies under anesthesia.
What is the standard treatment for pts with oropharyngeal lesions with metastasis to cervical lymphatics?
excision of tumor + postop adjuvant chemoradiation (cisplatin + IMRT)
*IMRT (intensity modulated radiation therapy)= better for for sparing unwanted tissue radiation.
What happens unfortunately to most pts receiving radiation therapy to the head and neck?
- dysphagia development
Are HPV+ neck tumors more or less responsive to treatment?
MORE with higher 5 year survivals.
** What is essential for any head and neck pathology?
- comprehensive head and neck exam
** How are the majority of occult primary tumors in oropharyngeal tonsillar tissue being identified?
- with advances in robotic surgery
Does adult head and neck mass have a broad differential?
- YES (infection, lymphoma, branchial cleft cyst, parotid neoplasm, lipom, thyroglossal duct cyst, metastasis…)
