Small spot on the left arm is<unk> -cell cancer<unk> . Gross pathology specimen<unk>  <unk>  usually presents as a firm nodule (up to 2 cm diameter) or mass (>2 cm diameter). These flesh-colored, red, or blue tumors typically vary in size from 0.5 cm (less than one-quarter of an inch) to more than 5 cm (2 inches) in diameter and may enlarge rapidly. Tumors can present as painless, tender or itchy, and other<unk>  manifestations as papules or plaques have also been reported. Although<unk>  may arise almost anywhere on the body, it is most commonly found in sun-exposed areas such as the head, neck or extremities. Five key attributes of<unk>  were summarized in 2008 in the acronym AEIOU (Asymptomatic/lack of tenderness, Expanding rapidly, Immune suppression, Older than 50 years, and Ultraviolet-exposed site on a person with fair skin). Ninety percent of<unk> 's have 3 or more of those features.<unk>  is sometimes mistaken for other histological types of cancer, including basal<unk>  carcinoma, squamous<unk>  carcinoma, malignant melanoma, lymphoma, and small<unk>  carcinoma, or as a benign cyst.<unk> s have been described in children, however pediatric cases are very rare.<unk> -cell cancers tend to invade locally, infiltrating the underlying subcutaneous fat, fascia, and muscle, and typically metastasize early in their natural history, most often to the regional lymph nodes.<unk> s also spread aggressively through the blood vessels to many organs, particularly to liver, lung, brain, and bone.
Merkel-cell carcinoma
Basal-cell carcinoma
Lymphoepithelioma
Trichoepithelioma
Angiokeratoma
Onychomatricoma
Sebaceous carcinoma
Generalized trichoepithelioma