Lectin-binding sites in clear cell acanthoma

Clear Cell Acanthoma with Malignant Cytologic Features: A Case Report and Review of the Literature

Clear cell acanthoma (CCA) is classically considered a benign epidermal tumor, although rare case reports have described CCA with malignant features. Here, we present a case of a patient with a biopsy proven CCA that regrew post-biopsy and was subsequently completely excised. Histologic examination of the tumor in the excision specimen revealed malignant cytologic features that were not present in the initial biopsy. A review of the literature identified five additional cases of CCA with similar malignant cytologic features. On analysis, common histopathologic characteristics included cellular pleomorphism, increased nuclear-to-cytoplasmic ratio, prominent nucleoli, and atypical mitotic figures. We support the designation of atypical clear cell acanthoma for these entities with features of both CCA and significant cytologic atypia. As none of these cases exhibited clinically aggressive behavior, further study is warranted.

Clear cell acanthoma: a rare clinical diagnosis prior to biopsy

BACKGROUND

Clear cell acanthoma is a rare, benign epidermal tumor with a clinical hybrid appearance and a distinct histological one. It is frequently mistaken for other clinical lesions.

OBJECTIVE

To evaluate the frequency that clear cell acanthoma was listed in the clinical differential diagnosis of histologically confirmed specimens.

METHODS

A regional dermatopathology lab database was evaluated from January 1998 through March 2008 for histologically diagnosed cases of clear cell acanthoma. Clinical data that was submitted with these cases including differential diagnoses was analyzed.

RESULTS

During this time period of review, 411 histologically confirmed cases of clear cell acanthoma were identified. This entity was listed as a diagnostic possibility in 11 (2.7%) of the cases.

CONCLUSION

Clear cell acanthoma was rarely listed amongst the differential diagnosis of biopsy proven specimens. This may be due to a variable clinical appearance with overlapping features of several other lesions making it difficult to distinguish, or an entity that is rare and not frequently suspected. Additional studies with dermatoscopy may help to further delineate the reasons for the low diagnostic sensitivity.

N-linked neutral oligosaccharides in the stratum corneum of normal and ichthyotic skin

N-Glycan oligosaccharides are thought to play multiple, important roles in a variety of biological events. However, N-glycan profiles in the stratum corneum of human skin have not yet been studied in detail. To clarify the N-glycan profiles in the stratum corneum of normal and ichthyotic epidermis, N-glycan profiles were studied by high-performance liquid chromatography using normal human epidermal samples and scales from hyperkeratotic skin of ichthyosis patients. Chromatograms of patient scale samples showed unique alterations in three peaks eluted at 15.8, 18.8 and 26.9 min. The N-glycan profiles were significantly altered in ichthyotic hyperkeratotic skin compared with normal non-hyperkeratotic controls. These findings indicate the reduction of N-acetylglucosaminyltransferase II and fucosyltransferase 8 activities. Alteration of N-glycan structures in hyperkeratotic skin suggests the biological role of N-glycans in keratinization.

Microassay analyses of protein glycosylation

To accurately characterize the carbohydrate moieties of oligosaccharide chains in glycosylated proteins, it is necessary to distinguish exactly which types of oligosaccharides are present at which site. We describe lectin overlay assays, which take advantage of the ability of lectins to distinguish between different types of glycoproteins via recognition of terminal sugars, thus allowing the chain type and peripheral antigenic components to be determined. Three microassays involving lectins are reported in this paper: non-protease-treated intact glycoproteins; glycopeptides released by prior digestion of the glycoprotein and then separated by HPLC; and release of sugars from glycoproteins by hydrazinolysis and then coupling them to a multivalent support.

Disseminated eruptive clear cell acanthoma--a case report with review of the literature

Clear cell acanthoma (CCA) is a benign epidermal tumour with distinctive and uniform clinical and histological features. Although solitary lesions are the rule, some cases of multiple CCA, rarely with more than 10 lesions, have been previously reported. Only 22 cases of multiple CCA have been described in the English literature to date. A healthy 32-year-old woman is reported, with approximately 400 asymptomatic rounded papules, on the upper and lower extremities. Multiple skin biopsies showed the typical histological pictures of CCA. This case appears unusual because of the presence of numerous lesions scattered on the upper and lower extremities. For this reason it could be classified as disseminated eruptive CCA.

Newly established human pancreatic carcinoma cell lines and their lectin binding properties

Two human pancreatic carcinoma cell lines, designated HuP-T3 and HuP-T4, were established from the ascites of pancreatic cancer patients with carcinomatous peritonitis. The cell lines were grown in monolayer cultures and had population doubling times of 38.6 and 37.1 h, respectively. HuP-T4 secreted large amounts of CEA and CA19-9 into the medium, and HuP-T3 produced a small amount of CEA, but no CA19-9. Both cell lines showed tumorigenicity in nude mice. Histologically, the HuP-T3-derived tumor was poorly differentiated adenocarcinoma, and the HuP-T4-derived tumor was well differentiated papillotubular adenocarcinoma. In lectin histochemistry at both light and electron microscopic levels, the most striking difference between the lectin binding properties of the two cell lines and those of control normal pancreatic ductal cells was that soybean agglutinin (SBA) bound to both cell lines, but not to controls. These newly established cell lines should be useful models that will contribute to clarifying the biological and biochemical characteristics of pancreatic cancer.

Keratoacanthoma with glandular proliferation

A case of keratoacanthoma (KA) with glandular proliferation was reported. The tumor was a firm, dome-shaped, elevated nodule on the cheek of an 82-year-old Japanese male. Generally, the tumor showed the typical histopathological features of KA; slight nuclear atypia and mitotic figures were present in a cup-shaped proliferation of keratinocytes and, in the center of the lesion, a keratin-filled crater with nests of dyskeratotic and acantholytic cells was seen. In the bottom of the lesion, a glandular structure forming branching, thin lumina was observed. The epithelium of the lumina was made up of two or more layers of columnar or cuboidal cells without keratinization. Tall columnar cells with oval nuclei were located in the luminal row and small cuboidal cells with round nuclei and scanty cytoplasm were in the outer layer. Immunohistochemical staining revealed that only the glandular structure was carcinoembryonic antigen positive. Lectin binding patterns observed in the glandular proliferation were similar to those reported for the apocrine gland. KA sometimes exhibits an adenoid structure in its lesion because of acantholytic changes. However, KA associated with true glandular proliferation has not been reported as far as we know, and our case is the first reported one. KA is thought to be a tumor of follicular origin, and the glandular proliferation observed in the present case seemed to have certain characteristics that suggest its apocrine origin.