Tumor definitions for cutaneous carcinoma of the HNa
| T Category | T Criteria |
|---|---|
| Tx | Primary tumor cannot be identified |
| Tis | Carcinoma in situ |
| T1 | Tumor ≤2 cm in greatest dimension |
| T2 | Tumor >2 but ≤4 cm in greatest dimension |
| T3 | Tumor >4 cm in maximum dimension or minor bone erosion or perineural invasion, or deep invasionb |
| T4a | Tumor with gross cortical bone/marrow invasion |
| T4b | Tumor with skull base invasion and/or skull base foramen involvement |
↵a This new chapter in the eighth edition should be used for all HN cutaneous malignancies except the eyelid and cutaneous melanoma and Merkel cell carcinoma. Lip tumors are now staged using this table. Table adapted with permission of the American Joint Committee on Cancer, Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual.1
↵b Deep invasion is defined as invasion beyond the subcutaneous fat or >6 mm (as measured from the granular layer of adjacent normal epidermis to the base of the tumor). Perineural invasion for the T3 classification is defined as tumor cells within the nerve sheath of a nerve lying deeper than the dermis or measuring ≥0.1 mm in caliber or presenting with clinical or radiographic involvement of named nerves without skull base invasion or transgression.