H, peanut lectin receptor, and carcinoembryonic antigen distribution in keratoacanthomas, squamous dysplasias, and carcinomas of skin

Pattern of TGFbeta receptor 1 expression differs between kras-mutated keratoacanthomas and squamous cell carcinomas of the skin

PURPOSE

Increasing evidence indicates that TGFbeta- and EGFR-signaling is involved in the pathogenesis of keratoacanthoma (KA) and squamous cell carcinoma (SCC) of the skin. We analyzed the expression pattern of TGFbeta-signaling components and screened for mutations in tgfbetaR1, egfr, kras and braf in KAs and SCCs.

METHODS

Immunohistochemical analysis of TGFbeta1, TGFbetaR1, TGFbetaR2 and phospho-SMAD2/3 was performed on skin tumors (29 KAs, 30 well and 31 moderately differentiated SCCs). Mutation screening in hotspot regions of tgfbetaR1, egfr, kras and braf was performed through pyrosequencing of tumor DNA.

FINDINGS

Expression of TGFbeta1, TGFbetaR1 and p-SMAD2/3 was increased in tumors as compared to surrounding skin. In KAs characteristic strong discontinuous membranous TGFbetaR1 expression pattern frequently associated with kras mutation was noted. SCCs showed continuous TGFbetaR1 expression, stronger p-SMAD2/3 expression and less frequent kras mutations. In tumors at sun-exposed sites stronger TGFbetaR1 expression was noted. One SCC showed tgfbetaR1 mutation, but no other mutations were found.

CONCLUSION

Although tgfbetaR1 germline mutations cause inherited KAs and our finding of strong discontinuous membranous expression in KAs suggests accumulation of functionally altered protein, we found no tgfbetaR1 mutations or influence on TGFbeta-signaling, but frequent kras mutations in this subgroup of KAs. Characteristic TGFbetaR1 expression pattern in KA can facilitate histopathologic distinction from SCC.

p16 Expression in Keratoacanthomas and Squamous Cell Carcinomas of the Skin: An Immunohistochemical Study

Context.—Distinguishing between keratoacanthoma (KA) and squamous cell carcinoma (SCC) is not an uncommon histologic diagnostic dilemma.

Objective.—To determine if p16 expression is useful in the differential diagnosis of SCC and KA.

Design.—We studied the expression of p16 by immunohistochemistry in 24 KAs, 24 infiltrating SCCs of the skin, 4 histologically indeterminate lesions, and 8 nonmalignant keratoses.

Results.—A range of immunohistochemical p16 expression was seen in KAs and SCCs in terms of the thickness of lesional staining and the percentage of cells staining. No significant difference in measures of p16 expression was identified among the KAs, the SCCs, the indeterminate lesions, or the benign keratoses.

Conclusions.—These findings suggest that p16 is not a useful marker to distinguish between KA and SCC, supporting the similarity between the 2 lesions; p16 alterations appear to play a role in the pathogenesis of both KA and SCC.

Keratin profile of intraepidermal cells in Paget's disease, extramammary Paget's disease, and pagetoid squamous cell carcinoma in situ

BACKGROUND

Although the histopathologic differential diagnosis of pagetoid neoplasms is broad, unique histopathologic identifiers and clinical correlation can often identify the process. However, in the case of mammary Paget's disease (MPD) or extramammary Paget's disease (EPD) without an obvious underlying malignancy, distinction from pagetoid squamous cell carcinoma in situ (PSCCIS) can be challenging. Our goal was to better define the immunohistochemical staining patterns of these three entities in the hope of determining distinctive staining patterns.

METHODS

We evaluated nine cases of PSCCIS, five cases of MPD, and 10 cases of EPD with the immunohistochemical antibodies CAM 5.2 and CK 5/6. In addition, only PSCCIS was stained with CK 7, as the staining patterns of CK 7 in MPD and EPD are well known from prior studies.

RESULTS

CAM 5.2 diffusely stained all cases of MPD and EPD and failed to stain any case of PSCCIS. Furthermore, CK 7 only focally stained two of the 10 cases of PSCCIS. CK 5/6 was difficult to interpret due to the high functional background staining of the normal keratinocytes in the epidermis.

CONCLUSIONS

Based on these results, our data supports the use of CAM 5.2 and CK 7 immunoperoxidase markers in differentiating between difficult cases of PSCCIS and MPD or EPD. An antibody panel consisting of S-100, CAM 5.2, and CK 7 will aid in the accurate diagnosis of almost all pagetoid neoplasms of the breast or genital skin.

An immunohistochemical study of the apocrine type of cutaneous mixed tumors with special reference to their follicular and sebaceous differentiation

An immunohistochemical analysis of 8 cases of the apocrine type of cutaneous mixed tumor is reported. Histologically, 7 cases of the tumor were suggested to have follicular and/or sebaceous differentiation. Carcinoembryonic antigen (CEA), epithelial membrane antigen and gross cystic disease fluid protein-15 were present in the inner surface and/or in the luminal cell bodies of the tubular structures. CEA and non-specific cross-reacting antigen were also detected in the keratinous cysts. Positive reactions for S-100 protein and vimentin were observed in the solid nests, the outer layer of the tubular structures and some stromal cells. However, smooth muscle actin was only focally expressed in the outer cells of the tubular nests in one case. Involucrin was positive in the inner layers of the keratinous cysts. Various staining patterns were observed in the keratin immunohistochemistry. The solid nests showed heterogeneous expressions of CK1/5/10/14, CK7, CK10/11, CK14, CK8/18 and CK19. The inner cells of the tubular structures were constantly positive for CK7, CK8/18 and CK19, and heterogeneously for CK1/5/10/14, CK10/11 and CK14. The outer cells were heterogeneously positive for CK1/5/10/14 and CK14. The keratinous cysts showed positive reactions for CK1/5/10/14 throughout the whole cell layers, and for CK14 in the basal layer. The inner layers in some keratinous cysts expressed CK6, CK10/11 and CK17, but only CK10 in others. CK13 was positively stained in the transitional portion between the matricial structure and the column of shadow cells in the cyst wall in only one case. When compared with the immunohistochemistry of the normal skin, the apocrine type of cutaneous mixed tumor can show various immunophenotypical patterns similar to those of entire structures of hair follicles, sebaceous glands and all components of apocrine glands, that is to say, the folliculosebaceous-apocrine unit.

Premalignant keratinocytic neoplasms

Premalignant keratinocytic keratoses are common, especially in pale-complected persons in whom they appear most often as an actinic keratosis. Although the actinic keratosis has a very low malignant potential, arsenic, tar, thermal, scar, reactional, and radiation keratoses may be more clinically aggressive. This article discusses these premalignant keratinocytic neoplasms.

Keratoacanthoma: a deficient squamous cell carcinoma? Study of bcl-2 expression

Ten keratoacanthomas with both proliferative and regressive histologic features along with 10 well-differentiated squamous cell carcinomas were examined using immunohistochemistry for the expression of bcl-2, a protooncogene recently recognized to be involved in protecting cells from undergoing apoptosis. The squamous cell carcinomas had a modest but diffuse staining pattern, while the proliferative keratoacanthomas stained only at the basal cells and only rare cells stained positively in the regressive keratoacanthomas. The degree and pattern of staining suggest a loss of bcl-2 expression with tumor maturity in keratoacanthoma and a possible role in their ultimate involution.

Keratoacanthoma in the Immunocompromised Patient - Surgical Concerns

KM Singleton, SF Morris, a Freiberg. Keratoacanthoma in the immunocompromised patient - Surgical concerns. Can J Plast Surg 1994;2(3): 108-112. It is well known that clinical and histological differentiation between keratoacanthoma and squamous cell carcinoma is often difficult. The two lesions share many common features, but have very different outcomes. Both occur with increased frequency in immunosuppressed patients. This report documents two cases of histologically confirmed keratoacanthoma in immunosuppressed patients. These lesions were excised but had frequent recurrences and in both cases underwent histologically proven malignant transformation. The purpose of this report is to demonstrate the potentially aggressive nature of keratoacanthomas in the immunocompromised patient.