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Page 4 of 14 Woods et al. J Cancer Metastasis Treat 2022;8:22 https://dx.doi.org/10.20517/2394-4722.2022.28

Cutaneous sarcoma
Regional lymph node metastasis is reported at up to 23% in angiosarcoma and 10%-20% in pleomorphic
[41]
[42]
dermal sarcoma . However, other non-melanoma cutaneous malignancies of the head and neck, such as
atypical fibroxanthoma, leiomyosarcoma, or dermatofibrosarcoma, rarely spread regionally, with rates less
[43]
than 10% in most of these tumors .
CLINICAL ASSESSMENT
Clinical evaluation of the entire skin of the head and neck, including the scalp, must be performed to assess
for multifocal lesions or in-transit metastatic disease. A thorough examination of the parotid and neck
should be performed in all patients with cutaneous malignancy of the head and neck. In cases that present
with clinical nodal disease, anatomical structures are particularly important to consider, including
underlying cartilage, underlying bone, parotid gland, external auditory canal, temporomandibular joint,
lateral temporal bone, motor nerves, such as the facial nerve branches, and cutaneous sensory nerves, such
as the greater auricular and auriculotemporal nerves. For facial skin lesions, involvement of the nasal
cartilages and tarsal plates for lesions of the eyelid, as well as the involvement of the terminal divisions of the
trigeminal nerve, should be carefully assessed.

SCC has a significant propensity for perineural spread or direct nerve invasion by nodal disease, and so
particular care must be taken to assess and manage sensory and motor nerves in these cases. Thorough
clinical examination should also include the extent of involvement of the skin, particularly in morpheaform
BCC and dermal lymphatic permeation by aggressive cancers.

Metachronous presentation of regional lymph node metastasis from NMSC is common and can be difficult
to distinguish from primary mucosal site metastasis. In these cases, histological assessment, such as for
high-risk human papillomavirus by in situ hybridization, can be helpful, and a thorough evaluation for a
mucosal primary is critical.

For clinically suspected nodal disease, as well as for primary tumors with a high risk of nodal involvement,
imaging should be performed to further evaluate the presence and extent of nodal metastases. This typically
will include contrast-enhanced computed tomography (CT) scanning of the head, neck, and chest. CT scans
are also valuable to assess bone invasion by primary tumors in extensive lesions. Magnetic resonance
imaging (MRI) is valuable for the assessment of suspected perineural invasion or parapharyngeal
involvement, while Positron emission tomography/CT imaging can be used in some cases for the
assessment of distant metastases, in addition to ruling out a mucosal primary site in those with
metachronous presentations. Ultrasound-guided fine-needle aspiration or core biopsy can be used to
establish diagnosis.

STAGING
NMSC of the head and neck is staged according to the 8th edition of the American Joint Committee on
Cancer (AJCC) tumor, node, metastasis (TNM) classification system . For tumors involving the temporal
[44]
[45]
bone, the most commonly used staging system is the modified University of Pittsburgh system .
There has been some debate around the use of the AJCC staging system in cutaneous SCC [46,47] . The nodal
system is the same as for mucosal SCC, but it is likely that stratification does not adequately reflect the
differences between nodal spread of mucosal and cutaneous SCC [48,49] . For example, very high rates of
extranodal extension in cutaneous SCC means that nodes greater than 6 cm in size without extranodal
extension are extremely rare and so the N3a stage may be better reclassified based on other features such as