Diagnosis and management of uncommon cutaneous cancers.

Abstract

Uncommon types of cutaneous cancers are mainly cited in the literature as case reports and their etiology, pathogenesis and prognosis have to be surmised because of their rarity. Within this group exist the rare and also the unusual, for instance a relatively common carcinoma arising in a strange circumstance. Initial management of such tumors involves taking a history and performing a thorough examination, allowing a diagnosis to be made. These tend to follow one of three patterns: the lesion is confidently recognized; the lesion is unknown but a likely diagnosis can be made and; the lesion is unknown. It is within the latter two groupings that the uncommon cutaneous cancers exist. A biopsy is then performed to confirm the diagnosis. For large lesions a punch or incisional biopsy is taken which must include a portion of normal skin at the lesion edge. If the lesion is small enough to allow direct closure, an excision biopsy is performed, with a minimum margin of 2mm. Shave biopsy can be employed to confirm a diagnosis, but care must be taken that the subsequent management of the lesion is not adversely affected. With the rare tumors diagnosis can be difficult and there may not be enough tissue in a biopsy for a definitive diagnosis. The whole lesion may therefore need to be excised to obtain a confident diagnosis with further surgical treatment planned as required. Once the diagnosis is established a decision on the method of treatment can be made. The limited literature would suggest that rare skin tumors are unresponsive to radiotherapy and chemotherapy, so the mainstay of treatment is surgery. When there are no established guidelines for the treatment of a particular rare tumor a pathologist can usually provide advice as to the probable nature of the lesion. This allows surgical treatment to be positioned into one of three main groups: lesions that behave like basal cell carcinomas (BCC); lesions that behave like squamous cell carcinomas (SCC) and; lesions that behave like soft tissue sarcomas (STS). It is helpful to have a management plan into which each variety of rare tumor can be fitted, giving guidance as to the best and most appropriate management. Grouping treatment into BCC, SCC or STS-like treatment has been useful. As more becomes known regarding these malignancies their subsequent management can be adjusted accordingly. Currently, it would appear wise to treat each under a broader subgroup.