Solid organ transplant recipients have a high incidence of cutaneous squamous cell carcinoma and often develop multiple and aggressive tumours. This retrospective study based on the Swedish organ transplant cohort, focuses on the deaths caused by cutaneous squamous cell carcinoma and aims to elucidate the clinicopathological features of these tumours. The cohort comprised 5931 patients who underwent organ transplantation during the period 1970 to 1997 and were registered in the Swedish In-patient Registry, Cancer Registry and Causes-of-Death Registry. A total of 544 cutaneous squamous cell carcinomas in 201 patients were re-examined. The dominating size of the tumours was 5-10 mm and one-third of the tumours were removed by methods other than excision surgery. Well-differentiated tumours and Clark level IV were predominant. Seven patients died from their tumours, all of which were localized on the head. The principal site of metastasis was the parotid gland. The mean duration between date of transplantation and death was 10.4 years (range 6-17 years). Mortality from cutaneous cell carcinoma was compared with that of the general population. There was a highly increased risk; standardized mortality ratio 52.2; 95% confidence interval 21.0-107.6. However, the mortality rate in the Swedish cohort appears to be lower than what has been reported previously from other countries.

We recommend that diagnosed ESFA shall be completely excised or followed, in view of the risk of developing carcinoma.

A low risk to develop melanoma was found in AD patients. However, the results must be interpreted with caution since the small number of expected cases of melanoma makes the risk estimate sensitive to chance effects. We hypothesize that formation of naevi and progression to melanoma is counteracted by the inflammatory process in the skin of AD patients.

Onychomatricoma is a rare tumor that appears to originate from cells of the nail matrix. Three cases of onychomatricoma that met Perrin et al.'s1 histologic criteria of onychomatricoma are described. However, using a single term to classify all three tumors ignores the apparent microscopic differences that exist among them. To demonstrate better the spectrum of so-called onychomatricoma and properly acknowledge the noticeable disparity among our cases, a series of terms is proposed. This terminology is based on the histologic spectrum of epithelial-stromal ratio of stromal cellularity and of extent nuclear pleomorphism. Use of such criteria has a precedent in the classification of follicular and odontogenic fibroepithelial neoplasms. This new nomenclature includes "unguioblastoma" for tumors with a predominant epithelial component and "unguioblastic fibroma" for tumors where a cellular stroma is more prominent and characteristic. The term "atypical unguioblastic fibroma" is used to describe a third rare neoplasm, in which the cellular stroma shows nuclear pleomorphism and atypia with an increase of mitotic activity.

In this study, we have found a high incidence of EBV-specific expression in posttransplant cutaneous squamous cell carcinomas. These results suggest that at least some of the skin cancers developing in immunocompromised heart transplant recipients are associated with EBV.