Rodent ulcer is seen in:

Basal cell carcinoma most often affects white adults, especially those with fair complexions. Although most patients are older than 40 years at diagnosis, some lesions are detected as early as the second decade of life, particularly in patients with red or blonde hair and blue or green eyes. Males are affected about twice as often as females; however, among young patients, there is a female predilection (possibly due to tanning bed use). Approximately 80% of lesions occur on the head and neck, with the remainder involving the trunk and limbs. The most common clinicopathologic variant, nodular (nodulo-ulcerative) basal cell carcinoma, begins as a firm, painless papule that slowly enlarges and develops a central depression or umbilication. Telangiectatic blood vessels usually are evident within the rolled border surrounding the central depression. When the lesion is pressed, a characteristic pearly opalescent quality is discerned. Expanding ulceration often develops in the central depression, and the patient may show intermittent bleeding followed by healing. Untreated lesions continue to enlarge slowly with ulceration and destruction of underlying structures—hence the term rodent ulcer. Destruction of underlying bone or cartilage may occur, but metastasis is extremely rare. Ref: Oral pathology Neville, 4th ed page no 397