See: Royal College of Pathologists. Datasets for head and neck carcinoma and salivary neoplasms histopathology reports. London. 2005.
Basic rules are applied to carcinomas arising at various sites in the upper aerodigestive tract (lip, oral cavity, pharynx, nasal cavity, paranasal sinuses and larynx), 95% of which are squamous cell carcinoma.
The surgeon should mark clinically relevant resection margins in the primary specimen and lymph node territories in neck dissections.
Prognosis relates to carcinoma: Type
— e.g. keratinizing squamous carcinoma vs. undifferentiated nasopharyngeal carcinoma. This also influences treatment modality, e.g. surgery in the former, chemo-/radiotherapy in the latter.
— the majority are moderately differentiated but identify well and poorly differentiated lesions. Base on the most aggressive area (medium magnification field).
— maximum diameter (mm): macroscopic or microscopic, whichever is greater.
— maximum depth of invasion (mm) below the luminal aspect of the surface measured from the extrapolated level of the adjacent mucosa. At least one block per cm diameter of the tumour is required and the whole lesion is submitted if less than 1 cm in maximum dimension.
— a cohesive vs. non-cohesive pattern of infiltration. The latter equates to single cells, small groups or multiple thin (<15 cells across) strands of cells at the deep aspect of the tumour.
Margins of excision >5mm clear
1-5 mm close to; also high risk of recurrence if the invasive edge is non-cohesive or shows vascular invasion <1 mm involved.
Note also the presence of severe dysplasia at the resection edge.
Lymphovascular and perineural spread
— strong indicators of local recurrence.
— distinguish erosion of the cortex from infiltration of the medulla.
— number identified and number involved at each anatomical level of the neck dissection. A typical radial neck dissection without previous chemotherapy or radiotherapy should yield an average of 20 nodes.
— an important prognostic factor is involvement of the lower cervical nodes, that is level IV (lower jugular chain deep to the lower one-third of sternocleidomastoid muscle) and level V (posterior triangle of neck behind the posterior border of sternocleidomastoid).
— maximum dimension of the largest nodal deposit.
— extracapsular spread.
— the significance of micrometastases is uncertain but should be counted as involved.
— persistent cervical lymph node enlargement in an older patient is commonly malignant due to either lymphoma or metastases. The latter are generally due to head and neck tumours, particularly mucosal squamous cell carcinomas, malignant melanoma of skin and thyroid gland carcinoma. Pharyngeal and laryngeal lesions should also be considered and once a tissue diagnosis has been obtained by FNA, panendoscopy of the upper aerodigestive tract is undertaken to establish the primary site. CT, MRI scan and thyroid ultrasound are also used for investigation and staging. A small minority (10%) can be due to non-head and -neck lesions, e.g. lung, stomach, prostate or testis. Patients can present with their metastatic disease, the occult primary being in the nasopharynx, posterior one-third of tongue, tonsil or hypopharynx. Neck dissection is either therapeutic (to remove metastases) or elective in a clinically negative neck to avoid any such future possibility. This decision will depend on the risk factors present, age, and fitness of the patient. Extent of resection relates to the tumour type, site and expected pattern of spread and is usually more limited (selective neck dissection, e.g. levels I-II or II-IV) in elective cases. Therapeutic dissection (radical or modified radical, levels I-V ± sternomastoid, internal jugular vein, spinal accessory nerve and sub-mandibular gland) aims to give maximum disease clearance where there are large (>6cm), multiple deposits, extranodal spread or recurrent disease. Positive lymph nodes (>2) in the resection warrant postoperative radiotherapy. Head and neck cancer specimens should also be interpreted in the light of any previous radiotherapy or chemotherapy due to potential morphological alterations and tumour regression that may make accurate staging more difficult.
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