To understand the role of epidermal cells in the pathogenesis of lichen amyloidosus (LA) and macular amyloidosis (MA).
We carried out immunohistochemical investigations on cytokeratins (CKs) in amyloid deposits in formalin-fixed and paraffin-embedded tissue specimens from eight persons with LA and 12 with MA. The primary antibodies of CK1-8 (AE3), CK10 (DEK-10), CK14 (LL002), CK17 (E3), CK18 (DC10), CK19 (KS19.1), CK5/6/18 (LP34) and CK8/18 (5D3) were used in the study.
In amyloid deposits, immunoreactivity with only two monoclonal antibodies (CK1-8 and CK5/6/18) was observed in 14 cases (eight LA and six MA), confirming the hypothesis that epidermal cells participate in amyloid formation of LA and MA.
All of the CKs detected in amyloid deposits were basic type (type II). It seems plausible either that acidic CKs might be degraded faster than basic types in amyloidogenesis or that paraffin-embedded tissue specimens are less sensitive than frozen tissue sections. The results of our study suggest that when paraffin-embedded specimens are investigated by immunohistochemical methods, CK5 antibody is useful in the diagnosis of LA and MA.
[Show abstract][Hide abstract] ABSTRACT: Objective: To analyse the presence of mast cells, melanophages and keratin deposition on dermis with cases of cutaneous amyloidosis and to compare with normal skin biopsy. Study design and methods: Primary localized cutaneous amyloidosis (PLCA) classifies into three major types: macular, lichen and nodular. Lichen amyloidosis (LA) and macular amyloidosis (MA) are clinically and histologically distinct varieties. Chronic pruritis, epidermal degeneration and degenerated epithelial cells are thought to contribute to the etiopathogenesis. We have reviewed the clinical and histopathological findings and differential diagnosis of 19 cases of LA and 5 cases of MA. The patients were clinically evaluated and biopsy procedures were performed. Paraffin sections were stained with hematoxylin-eosin, crystal violet, Congo red, toluidin blue, Masson-Fontana, PAS and anti-pankeratin antibody. Dermal and epidermal findings were examined under light microscopy. Results: Marked hyperkeratosis, keratinocyte degeneration, liquefaction degeneration of the basal layer, superficial perivascular infiltration of mononuclear cells were present in LA cases while these findings were slighter in MA cases. With PAS stain, degeneration of the basal membrane was observed and with crystal violet and Congo red stains amyloid deposits were demonstrated at the papillary dermis. Number of mast cells and melanophages accompanying these findings were also detected. Immunohistochemically, dermal keratin was demonstrated with using pankeratin antibody. Keratin deposits frequently found in papillary dermis. Conclusions: As a result, clinically suspicious PLCA cases are discussed with morphological and histochemical methods and it is emphasized that sequential biopsies should be taken in selected cases in the differential diagnosis of LA and MA.
[Show abstract][Hide abstract] ABSTRACT: Cytokeratins (CKs) are expressed specifically in the cytoplasm of epithelial cells. We investigated the expression of CKs immunohistochemically in basal cell carcinomas (BCCs), epidermis overlying tumour, and skin tumor-associated amyloidosis (STA). Twenty cases of BCC, 11 of which had STA were included to the study. The primary antibodies of CK1-8 (AE3), CK10 (DEK-10), CK14 (LL002), CK17 (E3), CK18 (DC10), CK19 (KS19.1), CK 5/6/18 (LP34), CK8/18 (5D3) were applied to the section immunohistochemically. In BCCs without STA, CK1-8, CK14 and CK17 antibodies were expressed by tumour tissue in all biopsy specimens. In the BCCs with STA, tumour tissue was immunoreactive always with CK1-8 and CK17 antibodies, and commonly immunoreactive with anti-CK 14 antibody. In the epidermis overlying tumour tissue, there was positive immunoreactivity with anti-CK 1-8, CK 5/6/18, CK 10 and CK 14 antibodies in all biopsy specimens. Anti-CK 17 antibody was also positive in 17 biopsy specimens. STA is immunoreactive with anti-CK1-8 in all specimens. There was mild staining with anti-CK5/6/18 and with anti-CK19 whereas no immunoreactivity with anti-CK10 and CK18 antibodies was found. In conclusion, we could not find a significant CK expression difference between BCCs with and without STA. Weak positivity and a few number of CKs were shown in STA when compared with those of BCC and epidermis overlying tumour tissue expressing the more variable CKs. Interestingly, although CKs coexpressed in pairs consisting of one basic and one acidic CK, we detected predominantly basic CKs in STA.
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