br Discussion Verrucous carcinoma of the skin and mucosa

Discussion Verrucous carcinoma of the skin and mucosa is an uncommon low-grade squamous cell carcinoma characterized clinically as a slowly but relentlessly enlarging warty tumor; histologically by local invasion with minimal, if any, dysplasia and biologically with a low incidence of metastasis. According to their anatomical localization, four types of tumors can be distinguished: (1) verrucous carcinoma of the oral cavity, also known as Ackerman carcinoma or oral florid papillomatosis; (2) verrucous carcinoma of the anogenital area, also referred to as giant condyloma of Buschke and Loewenstein or warty squamous cell carcinoma; (3) verrucous carcinoma occurring predominantly on the soles, also known as epithelioma cuniculatum or carcinoma cuniculatum, which shows an exo- and sometimes an endophytic growth; and (4) verrucous carcinoma occurring at other cutaneous sites, also referred to as cutaneous verrucous carcinoma or papillomatosis cutis. This terminology has not been uniformly applied, and a verrucous carcinoma at any site may thus be labeled as any of the aforementioned types. No term except “verrucous carcinoma,” site specified, is merited of probable value except to respect historical precedent. However, the term “carcinoma cuniculatum” should be used in reference to sites other than the soles only when the requisite cuniculate histology, referring to numerous sinus formations and keratin-filled crypts, is present. The incidence of carcinoma cuniculatum, a tumor most often observed on the soles, is unknown. It occurs mainly in men (79–89% of patients). Patients are predominantly older, with a mean age of 52–60 years (range 23–84 years). Cases of carcinoma cuniculatum at sites other than the soles, or cutaneous verrucous carcinoma arising elsewhere on the skin, such as in our case, are exceedingly rare. In our review of the literature published between 1981 and 2010, we found only 10 cases (summarized in Table 1) of carcinoma cuniculatum with facial involvement (except the lips and scalp). Six of the 10 patients (60%) were male; only one patient was female. The mean age was 60.9 years. Surgical excision was considered the treatment of choice for all patients, with a follow-up histone demethylase ranging from 1 year to 4 years; only one patient underwent prophylactic neck lymph node dissection. No recurrence or distant metastasis was reported. Our case is the first with nasal involvement. Compared with carcinoma cuniculatum, or cutaneous verrucous carcinoma, verrucous carcinoma of the oral cavity is an unusual but not a rare tumor, originally described in 1948 by Lauren Ackerman as a tumor of the oral cavity. It represents 2–12% of all oral carcinoma. Most patients are in their 5th decade or are older, and are also predominantly male. Both tumors are very well-differentiated forms of squamous cell carcinoma with locally destructive growth and rarely distant metastasis. However, cunicular structure and sinus tract formation are not always presented in verrucous carcinoma of the oral cavity. The pattern of cunicular structure is also different in each of the two types of tumors: oral verrucous carcinoma is an undulation from a verrucous surface, but cutaneous verrucous carcinoma descends from a flat surface. Other features that differ between the two tumors require further investigation. The pathogenesis of carcinoma cuniculatum is still unknown. Human papillomavirus and chemical carcinogens, such as tobacco and betel quid, may play a critical role in the development of specific tumors. Klima et al described previous chronic infection and long-standing scar tissue as crucial factors in the pathogenesis of cutaneous verrucous carcinoma. At the histological level, all sites of verrucous carcinoma are characterized by a prominent papillomatous configuration with hyperkeratosis, parakeratosis, acanthosis, papillomatosis, and granular cell layer vacuolization. The keratinocytes show minimal or no dysplasia and no disruption of the basement membrane. Blunt projections of a well-differentiated epithelium surrounded by edematous stroma and chronic inflammatory cells extend into the dermis, forming sinuses that are filled with keratin. Aird et al described a unique tumor, which they called epithelioma cuniculatum or carcinoma cuniculatum, considering the characteristic histological features of sinus formations and keratin-filled crypts, which result in the rabbit-burrow-like architecture of the tumor.