Squamous Cell Carcinoma

Follicular squamous cell carcinoma of the skin: a poorly recognized neoplasm arising from the wall of hair follicles

“…It is generally acknowledged that SCC of the skin arises from the epidermis rather than from cutaneous adnexa. Chronic exposition to sunlight is considered to be the most important factor in the development of the neoplasm 23 . Cumulative sun exposure progressively damages the keratinocytes of the epidermis, giving rise to architectural and cytologic alterations characterized by loss of normal maturation and polarity of cells that, in some cases, progress to invasive carcinoma.…”

Ber-EP4-Positive Phenotype Differentiates Actinic Keratosis from Superficial Basal Cell Carcinoma

“…Our findings and those of other investigators have shown that normal epidermal keratinocytes, and abnormal keratinocytes found in SIN and SCC, do not stain with Ber‐EP4. 4–7 Because the Ber‐EP4 antigen is not acquired during neoplastic transformation, 6,9 and since epidermal keratinocytes are known to be the precursor cells of AK (as well as SIN and SCC), 12 it is logical that these lesions are Ber‐EP4 negative.…”

“…It is well known that the overall prognosis of BCC, in terms of metastatic potential, is much better than that of SCC. 12,13 The belief of most practitioners that an AK may evolve into an SCC rather than BCC, appropriately warrants aggressive treatment. There is a great body of evidence in the literature indicating that AK may convert into SIN (SCC in situ), and then into invasive SCC; 14–23 however, BCC has also been associated with an antecedent AK.…”

“… 6,9 Since normal keratinocytes do not show Ber‐EP4 positivity, it is not surprising that SCC, thought to originate from keratinocytes, has stained negatively for Ber‐EP4. 9 Because AK, squamous intraepidermal neoplasia (SIN or SCC in situ), and SCC are thought to arise from epidermal keratinocytes, 12 we predicted that AK and SIN would not stain positively with Ber‐EP4. On the other hand, we anticipated that superficial BCC, recently proposed to arise from the outer root sheath of hair follicles, 13 would stain positively as shown in previous studies.…”

Plantar Verrucous Carcinoma: Report of a Case Treated with Boyd Amputation Followed by Reconstruction with a Free Forearm Flap

“…Human papillomavirus (HPV) also has a significant association with this carcinoma. HPV subtypes 6, 11, 16 and 18 have been detected in the tumor (8, 15, 18, 19); however, human papillomavuirus was not detected in most cases. Repeated weight‐bearing compression also may contribute to inducing the tumor; the sole is much more frequently affected than the instep.…”