Editorial

Classification of cutaneous squanfious cell carcinoma In this issue, Banks & Cooper describe 10 cases of a biologically aggressive cutaneous neoplasm that is probably much more common than currently appreciated. Because the lesion exhibits both malignant squamous and glandular components, the term adenosquamous carcinoma was applied and is appropriate. These lesions are probably identical to two neoplasms previously reported by Weidner and Foucar in 1985 (1). Other lesions that are similar may have been previously reported as squamous cell carcinoma with mucinous metaplasia (2), mucoepidermoid carcinoma, and even some adenoid squamous cell carcinomas (pseudoglandular squamous cell carcinomas). Based on the current study, adenosquamous carcinoma of the skin occurs primarily on the central face of adults. Histologically it exhibits a highly infiltrative pattern, prominent squamous differentiation superficially, and variable glandular differentiation in deeper areas. Mucin stains are positive not only in glandular foci but also in cytoplasmic vacuoles present in some squamous cells. Immunoperoxidase studies demonstrate carcinoembryonic antigen (CEA) within tumor cells, in cuticles lining lumens, and in luminal contents. Rare cells are also decorated with antibodies to S-100 antigen. These studies support true glandular and/or ductal differentiation. The clinical follow-up varied from 2 months to 6 years (mean 37 months), and clearly attests to the aggressive behavior of this neoplasm. Of 10 patients, 5 died from their disease and 2 are alive with extensive disease present. Much of the authors' discussion pertains to the possible origin of this neoplasm. Since the lesion exhibits definite glandular differentiation, and is a primary cutaneous neoplasm, some relationship to sweat gland structures is possible. The authors note that this neoplasm could be a more aggressive form of microcystie adnexal carcinoma (3) (sclerosing sweat duct carcinoma) (4) with which it does share some similarities. However, histologically adenosquamous carcinomas are predominantly squamous cell carcinomas, and most surgical pathologists would probably classify them as such.

This then brings up the classification of squamous cell carcinomas of the skin, or at least neoplasms that exhibit a prominent squamous cell or epidermoid component. Although there are, to the best of my knowledge, no entirely definitive and all inelusive classifications available, a host of tumors may fall into this category. The accompanying Table includes a variety of lesions which are histologically distinct, but often are simply regarded as "squamous cell carcinomas". Some of these are only histological curiosities, but an attempt has been made to identify those lesions that are generally considered to be biologically aggressive with significant metastatic potential. For interest, the lesions have also been divided into those which may be derived from or differentiate towards either epidermal or adnexal epithelium. Some arise from definable intraepithelial neoplasia. Others have a biologically important pathogenesis such as those associated with radiation injury or human papillomavirus. Still others, such as signet cell or clear cell variants, represent metabolic aberrations. Some of these neoplasms are uncommon, and statistically significant figures of the incidence of metastases have not been determined. Some, such as intraepidermal epithelioma with invasion, are controversial. Mucous membrane carcinomas have been intentionally excluded as noncutaneous. Undoubtedly there are additional neoplasms that may not have been listed. Finally, any of the listed lesions can probably become biologically aggressive if one or more of the following are met: poor differentiation, large total volume, deep or vessel invasion, and alteration by a carcinogenic or mutagenic therapy. What this classification does tell us is that not all squamous cell carcinomas are the same. It is therefore imperative that we, as pathologists, subclassify these neoplasms in order to supply clinicians with the necessary information to treat their patients in an appropriate fashion. Banks and Cooper have given us the incentive to evaluate carefully squamous cell carcinomas of the skin for glandular features, including utilizing mucin stains and antibodies to carcinoembryonic anti-

225

Barr gen. These authors have described another variant of cutaneous squamous cell carcinoma; not a histological curiosity, but a biologically aggressive tumor that should be remembered. Ronald J. Barr University of California, Irvine UC Irvine Medical Center, 101 City Drive South, Route 98, Orange, CA 96228, U.S.A.

Classification of cutaneous squamous cell carcinoma (SCC)* Epidermal related: Generally low risk - s e c arising in actinic keratosis - Verrucous and other HPV related SCC Variable or undetermined risk - Adenoid SCC - Clear cell SCC (5) - Signet cell SCC (6) - Spindle cell SCC Generally high risk - SCC arising in certain chronic conditions (burn scars, osteomyelitis, ulcers, discoid lupus) (7,8) - Radiation - induced SCC (9) - SCC arising in immunosuppressed host (10) - Denovo SCC (11)

Adnexal related: Generally low risk - Miscellaneous neoplasms with pilosebaceous or glandular differentiation N.O.S. - Tricholemmal carcinoma (12) Variable or undetermined risk - Miscellaneous neoplasms with pilosebaceous or glandular differentiation N.O.S. - Intraepidermal epithelioma with invasion (11) Generally high risk - Bowen's disease with invasion (11, 13) - Lymphoepithelioma-like carcinoma (14) - Adenosquamous carcinoma * Neoplasms with predominantly squamous eell features.

226

References 1. Weidner N, Foucar E, Adenosquamous carcinoma of the skin - an aggressive mucin and gland-forming squamous carcinoma. Arch Dermatol 1985: 121: 775. 2. Friedman KJ, Hood AF, Farmer ER. Cutaneous squamous cell carcinoma with mucinous metaplasia, J Culan Pathol 1988: 15: 176. 3. Goldstein DJ, Barr RJ, Santa Cruz DJ. Microcystie adnexal carcinoma: a distinct clincopathologic entity. Cancer 1982: 5: 566. 4. Cooper PH, Mills SE, Leonard DD, et al. Sclerosing sweat duct (syringomatous) carcinoma. Am J Surg pathol 1985: 9: 422. 5. Kuo T. Clear cell carcinoma of the skin - a variant of squamous cell carcitioma that simulates sebaceous carcinoma. Am J Surg Pathol 1980: 4: 573. 6. Cramer S, Heggeness L. Signet ring squamous cell carcinoma. Am J Clin Patho! 1989: 91: 488. 7. Sulica VI, Kao CF. Squamous cell carcinoma of the scalp arising in lesions of discoid lupus erythematosus. Am J Dermatopathol 1988: 10: 137. 8. Lifeso RM, Bull CA. Squamous cell carcinoma of the extremities. Cancer 1985: 55: 2862. 9. Martin H, Strong E, Spiro RH. Radiation - induced skin cancer of the head and neck. Cancer 1970: 25: 61. 10. Dinehart SM, Chu DZJ, Maners AW, Pollack S. Immunosuppression in patients with metastatic squamous cell carcinoma from the skin. J Dermatol Surg Oncol 1990: 16: 271. 11. Craham JH, Helwig EB. Premalignant cutaneous and mucocutaneous diseases. In: Graham et al., eds. Dermal pathology. Hagerstown: Harper & Row, 1972: 561. 12. Swanson PE, Cherwitz DL, Wick MR. Tricholemmal carcinoma (Abstr). J Cutan Pathol 1987: 14: 374. 13. Kao GF. Carcinoma arising in Bowen's disease (editorial). Arch Dermatol 1986: 122: 1124. 14. Swanson SA, Cooper PH, Mills SE, Wick MR. Lymphoepithelioma-like carcinoma of the skin. Modern Pathol 1988: 1: 359.

Classification of cutaneous squamous cell carcinoma.

Editorial Classification of cutaneous squanfious cell carcinoma In this issue, Banks & Cooper describe 10 cases of a biologically aggressive cutaneou...
4MB Sizes 0 Downloads 0 Views