Is the carbohydrate sialosyl-Tn a marker for altered,non-malignant activity in squamous epithelium in the head and neck region?

Cell surface carbohydrates are involved in many cell functions such as cellular differentiation, adhesion, and invasion. A carbohydrate, sialosyl-Tn (STn), is expressed in many human carcinomas but generally not in normal epithelia. In the oral mucosa, however, STn had recently been observed on basal cell in some lesions with epithelial hyperplasia and dysplasia. The aim of this study was to carry out a systematic investigation of STn expression on epithelial basal cells in hyperplastic, ‘borderline’ malignant, and malignant head and neck lesions, to see if the expression of STn is associated specifically with hyperplastic conditions. Using the primary monoclonal antibody TKH2, normal controls did not reveal STn. STn was detected on probably post-mitotic basal cells in hyperplastic head and neck lesions and on basal cells adjacent to cancers, but not within the carcinomas. A Ki67 antibody reacted with basal cells in other locations. The most highly differentiated lesions, such as focal epithelial hyperplasia and verrucous hyperplasia, revealed a high percentage (86 per cent in both cases) of STn reactivity. The least-differentiated verrucous carcinomas (VCs) and keratoacanthomas (KAs) did not express STn, in contrast to the highly differentiated VCs and KAs. These findings indicate that STn-negative cases may have a greater malignant potential that the STn-positive cases. In conclusion, STn expressed on basal cells is possibly a marker for non-malignant conditions with altered basal cell activity and for highly differentiated verrucous carcinomas.     

Extraocular sebaceous carcinoma accompanied by invasive squamous cell carcinoma: The first case report and consideration of histogenesis

A 61‐year‐old man presented with a dome‐shaped nodule, 1.2 cm in size, with a central crater covered by keratinous material near the left lateral malleolus. Histological findings demonstrated a basophilic circular cone in the center, surrounded and sharply demarcated by a broad eosinophilic area. The central conical mass was composed mainly of atypical basaloid cells intermingled with scattered atypical sebaceous cells with scalloped nuclei and microvesicular cytoplasms, suggesting sebaceous carcinoma. The peripheral area consisted of atypical keratinizing squamoid cells without sebaceous cells, suggesting invasive squamous cell carcinoma. Atypical sebaceous cells were positive for adipophilin. Atypical basaloid cells were positive for 34βE12 and CAM5.2. Peripheral squamoid cells were positive for 34βB4 and 34βE12 throughout, and were positive for LHP1 in the superficial layer. We herein describe the first case of extraocular sebaceous carcinoma accompanied by invasive squamous cell carcinoma, which might have arisen from biphasic differentiation of cancer stem cells.     

Maligne Epitheliale Tumoren: Teil I. Pathophysiologie und Klinik

Epithelial skin cancer is a major burden for western societies. In the 21^st century there will be a steady increase in the incidence of these tumors in the elderly population. The article summarizes the pathophysiology of epithelial tumors and gives a systematic outline of the different clinical features of keratinocytic tumors. Furthermore, the article gives an overview of inherited syndromes that predispose to malignant epithelial tumors.     

Natural course of keratoacanthoma and related lesions after partial biopsy: Clinical analysis of 66 lesions

There is some confusion regarding the classification of keratoacanthoma (KA) and related lesions that have crateriform architecture. We examined the clinical courses of 66 KA lesions and related lesions after a partial biopsy to clarify the nosological concept of KA. We histopathologically classified these lesions into five types: (i) KA at various stages (53 lesions); (ii) KA‐like squamous cell carcinoma (SCC) (3 lesions); (iii) KA with malignant transformation (3 lesions); (iv) infundibular SCC (5 lesions); and (v) crateriform SCC arising from solar keratosis (2 lesions). We analyzed the clinical course in each group. The regression rate of KA was 98.1% and that of KA‐like SCC/KA with malignant transformation was 33.3%. No regression was observed in either infundibular SCC or crateriform SCC arising from solar keratosis. Thus, KA is a distinct entity that should be distinguished from other types of SCC with crateriform architecture based on the high frequency of regression. The regression rate of 33.3% in KA‐like SCC/KA with malignant transformation indicated that KA lesions with an SCC component still have the potential for regression. However, this result also indicated that KA is biologically unstable, and some KA tend to evolve into conventional SCC with a gradual loss of the capacity for the spontaneous regression. Infundibular SCC and crateriform SCC arising from solar keratosis are fundamentally different from KA, not only according to the histopathological findings but also based on the biological properties.     

Follicular squamous cell carcinoma is an under-recognised common skin tumour

Current thinking assumes most cutaneous squamous cell carcinoma arise from the surface epidermis. Uncommon pilar and tricholemmal carcinomas are well recognised and recently authors have drawn attention to uncommon squamous cell carcinoma with predominant follicular infundibular differentiation. In contrast we propose that follicular (infundibular-tricholemmal) squamous cell carcinoma is exceedingly common and can be defined as follows: cytologically malignant tumour, abrupt connections to the epidermis (at follicular infundibula), infundibular and/or tricholemmal differentiation and lacking co-existent Bowen's disease or distinctive clinical-pathological features of keratoacanthoma. Recognition that many cutaneous squamous cell carcinoma are of follicular origin has major implications for differential diagnosis, staging, prognosis, management and future research.     

Keratoacanthoma formation after skin grafting: A brief report and pathophysiological hypothesis

Keratoacanthoma formation after skin grafting is rare. We report the third case in the literature of multiple keratoacanthomas developed at both split‐thickness skin graft donor and recipient sites. We provide possible explanations for this poorly understood phenomenon and highlight its implications on treatment options.     

EVALUATION OF CURETTAGE AND ELECTRODESICCATION IN TREATMENT OF KERATOACANTHOMA

The reports from all keratoacanthoma curettings which were submitted to a Brisbane pathology practice over a two year period were reviewed. Those followed up for less than 12 months were not included in the analysis, unless recurrence occurred. Of 150 submitted, 111 keratoacanthomas in 106 patients could be studied. The sex distribution was almost equal, and the mean age of patients was 65 years for females and 64 years for males. Four keratoacanthomas recurred over periods ranging from 3 to 26 months. Curettage and electrodesiccation is shown to be an efficient and effective form of therapy.     

The diagnostic value of imaging techniques for keratoacanthoma: A review

Keratoacanthoma (KA) is a fast-growing skin tumor with solitary KA being the most common type. KAs rarely metastasize and subside spontaneously. Although histopathology is the gold standard for the diagnosis of KA, its histopathological features are sometimes difficult to distinguish from those of other skin tumors. Imaging studies have certain advantages in the preoperative diagnosis of KA; they not only show the exact shape of the lesion but can also accurately determine the extent of the lesion. Combined with histopathological examination, these findings help establish a diagnosis. By summarizing the imaging features of KA, this article aimed to improve radiologists’ understanding of the disease and help in the clinical and differential diagnosis of KA.     

Eosinophil infiltration in keratoacanthoma and squamous cell carcinoma of the skin

The incidence of tissue eosinophilia in keratoacanthoma and in early and late cases of squamous cell carcinoma of the skin has been studied. Eosinophil infiltration of over 10 cells per high power field was found in 80 cases, and was not related to the size, site or aetiology of the lesions in which it was present. In cases where diagnostic difficulty arises between keratoacanthoma and well differentiated, keratinizing squamous cell carcinoma, if tissue eosinophilia is present the lesion is more likely to be malignant. Though in isolation the finding of an eosinophil infiltrate is not diagnostic it should be added to the list of criteria which help to distinguish these lesions. The pattern of tissue eosinophilia in late cases of squamous cell carcinoma was more extensive and there were two cases which showed massive tumour-associated tissue eosinophilia. This has previously been reported in squamous cell carcinoma at other sites, and may be related to the production of an eosinophilochemotactic factor.