Immunohistochemical staining for p16 is a useful adjunctive test in the diagnosis of Bowen's disease

Actinic keratosis with severe dysplasia and Bowen disease represent distinct pathways of intraepidermal squamous neoplasia: an immunohistochemical study

Intraepidermal squamous neoplasia is a precursor to invasive cutaneous squamous cell carcinoma. The most common type of intraepidermal squamous neoplasia is actinic keratosis (AK), although there is compelling clinicopathological evidence of a second distinct pattern of squamous dysplasia termed Bowen disease (BD). The distinction between these pathways of dysplasia has been inconsistently delineated in the literature. To further investigate the biological differences between AK and BD, a cohort of cases of intraepidermal squamous dysplasia including AK with mild/moderate dysplasia (n=26), AK with severe dysplasia (n=21) and BD (n=47) was prospectively collected. Immunohistochemistry was utilised to assess the protein expression of major tumour suppressor genes including p16, RB-1 and p53. Most cases of BD showed complete loss of RB-1 (∼80%), strong and diffuse positive staining for p16 (∼80%) ​and mutant pattern (diffusely positive or completely negative) of p53 (∼79%). However, lesions of AK showed loss of RB-1 in only 6%, strong and diffuse positive staining for p16 in 4% and mutant pattern of p53 in 85% of case (p<0.001). The statistically significant difference in RB-1 and p16 expressions between AK and BD confirms that the two morphologically distinct types of intraepidermal squamous neoplasia differ in protein expression of major tumour suppressor genes and provide evidence that they represent two distinct genomic pathways of squamous neoplasia. Recognition of clinical and genomic differences between different pathways of squamous neoplasia could potentially have an important role in predicting the biological behaviour and treatment of advanced tumours arising from these precursor lesions.

Human papillomavirus detection rates in Bowen disease: correlation with pelvic and digital region involvement and specific p53 immunostaining patterns

BACKGROUND

The relationship between human papillomavirus (HPV) and Bowen disease (BD) is not fully understood.

OBJECTIVES

To investigate the differences in HPV detection rates in BD samples across various body regions and analyse the expression patterns of p53, p16 and Ki-67 in relation to HPV presence.

METHODS

Tissue samples from patients diagnosed with BD, confirmed through histopathology, were retrospectively collected. Next-generation sequencing was used for HPV DNA detection. Immunohistochemistry (IHC) for p16, p53 and Ki-67 was performed.

RESULTS

Out of 109 patients with BD, 21 (19.3%) were HPV-positive. All identified types were α-HPVs, with HPV-16 being the most common. The HPV detection rate was significantly higher in the pelvic (9/13, 69%, P < 0.001) and digital (5/10, 50%, P = 0.02) areas compared with those in the other regions. HPV presence was significantly correlated with p53 negativity (P = 0.002), the p53 'non-overexpression' IHC pattern (P < 0.001) and p16-p53 immunostain pattern discordance (P < 0.001). Conversely, there was no notable association between HPV presence and p16 positivity, the p16 IHC pattern or Ki-67 expression.

CONCLUSIONS

Our findings suggest the oncogenic role of sexually transmitted and genito-digitally transmitted α-HPVs in the pathogenesis of BD in pelvic and digital regions.

GRAPHICAL ABSTRACT

Bowen disease is not synonymous with intraepidermal squamous cell carcinoma

The terms 'Bowen disease' and 'intraepidermal squamous cell carcinoma' are sometimes considered synonymous. In this paper we present historical, clinical, histological and molecular evidence that this is incorrect. The term Bowen disease should be reserved for a subset of intraepidermal squamous cell carcinoma with a distinctive and reproducible morphological pattern, described in detail by Bowen in 1912. One other common subset of intraepidermal squamous cell carcinoma represents progression of actinic keratosis. In some cases the separation of these two common patterns of intraepidermal squamous cell carcinoma can be challenging and there are patterns of intraepidermal squamous cell carcinoma which appear to represent other distinct pathways. However, there is emerging biological evidence to support this distinction and reason to suspect that the types of invasive squamous cell carcinoma which arise from these different pathways may show important clinical and biological differences, particularly in the era of targeted and immunomodulatory therapy for advanced disease.

Pagetoid Squamous Intraepithelial Neoplasia of the Vulva as a Mimicker of Vulvar Extramammary Paget Disease: Two Cases with Basal Layer Sparing

Human papillomavirus-associated vulvar intraepithelial neoplasia (high-grade squamous intraepithelial neoplasia [HSIL] or VIN of usual type) is a lesion characterized by atypia extending from the basal layer to the upper epidermis. There are only rare reports of vulvar intraepithelial morphology exhibiting a pagetoid pattern of intraepithelial dissemination. We herein report two cases of vulvar HSIL in which a pagetoid pattern of spread and a largely uninvolved basal layer represented a diagnostic pitfall for extramammary Paget disease. Nuclear atypia reminiscent of HSIL in addition to expression of p16, KRT5/6, and p40 were however in favor of pagetoid HSIL. Although there is morphological and immunohistochemical overlap between these two entities, an accurate diagnosis is important, since an erroneous diagnosis of vulvar extramammary Paget disease may lead to an extensive workup comprising radiological imaging, colonoscopy, and cystoscopy.

Seborrheic Keratosis With Malignant Transformation (Invasive or Noninvasive Squamous Cell Carcinoma Arising in Seborrheic Keratosis): A Clinicopathologic and Immunohistochemical Study of 11 Cases

ABSTRACT

Seborrheic keratosis is a common benign neoplasm composed of basaloid keratinocytes. However, little is known about the malignant transformation of the tumor. Eleven cases of seborrheic keratosis with malignant transformation were analyzed. The 11 patients included 5 male patients and 6 female patients with a median age of 75 years at diagnosis (68-90 years). The tumors arose at various sites from the scalp (n = 3) to the lower leg (n = 2). The median tumor size was 12 (10-32) and 40 (20-75) mm in 7 noninvasive and 4 invasive cases, respectively. One patient exhibited in-transit skin metastasis. Histopathology of the malignant components resembled porocarcinoma or inverted follicular keratosis. Bowenoid and pagetoid spreading was frequently observed. The malignant components expressed cytokeratin 5/6 (100%) and GATA3 (73%), but not cytokeratin 7 (0%), cytokeratin 19 (9%), BerEP4 (0%), c-kit (0%), and NUT (0%). No significant immunoreactivity of YAP1 was observed in any of the cases. Mutant-type immunostaining of p53 and PTEN was observed in 91% and 82% of the cases, respectively. An increase in p16 expression was seen in 6 (86%) of the 7 cases with noninvasive carcinoma, although a loss of p16 immunoexpression was seen in the invasive carcinoma component in 3 (75%) of the 4 cases. This study demonstrated that seborrheic keratosis can undergo malignant transformation, particularly in large-sized lesions in elderly patients. Malignant components mimic porocarcinoma or inverted follicular keratosis. Malignant transformation induced by TP53 and PTEN mutations and tumor invasion by CDKN2A inactivating mutations are suggested in this study.

The diagnostic value of p63, p16, and p53 immunohistochemistry in distinguishing seborrheic keratosis, actinic keratosis, and Bowen's disease

Seborrheic keratosis (SK), actinic keratosis (AK), and Bowen's disease (BD) are squamoproliferative disorders of the skin. Histologically, they may mimic each other and therefore, they might be misinterpreted, especially in small samples. The aim of this study is to clarify the expression of p63, p16, and p53 proteins in SK, AK, and BD and evaluate the efficacy of these markers in order to distinguish between the aforementioned lesions. A total of 46 cases were collected (15 SK, 16 AK, and 15 BD) and stained for p63, p16, and p53. The stain intensity and the cell distribution labeling were scored and then analyzed by SPSS software. All cases of BD which became positive for p53 revealed basal keratinocytes sparing. Instead, all or nearly all basal keratinocytes in AK cases were positive for this marker. These were also seen in p16 staining results and they were between AK and BD (P = .024). Our study demonstrates p16 and p53 are useful markers in separating AK and BD according to basal keratinocytes involvement and sparing, respectively.

[Impaired expression of cell-cycle regulatory proteins in seborrheic keratosis]

Seborrheic keratosis (SK) is a benign skin tumor of unknown etiology and pathogenesis. Many details remain unclear despite that there have been a number of studies of cell-cycle abnormalities.

AIM

to investigate the expression of the cell-cycle regulatory proteins p53 and p16 and the cell proliferation marker Ki-67 in SK.

SUBJECTS AND METHODS

The investigation used intraoperative SK material obtained from 130 patients. Tumors were removed from UV-exposed parts of the body in 63 (48%) patients and from the places that were more often closed in 67 (51.5%). An immunohistochemical (IHC) study was performed using monoclonal antibodies to p53, p16, and Ki-67.

RESULTS

A positive reaction with monoclonal antibodies to p53 was recorded in 66 (50.7%) SK samples. In 92.1% of cases, the expression of p53 was found in SK located at the sites that were most exposed to UV radiation (p=0.00001). A positive reaction with monoclonal antibodies to p16 was observed in all SK cases as cytoplasmic staining of more than 50% of the tumor cells: a strong staining in 63 SK samples (overexpression) and a weak staining in 67 SK ones. The level of p16 expression correlated with age (R=0.21; p=0.019) and SK location at the sites exposed to increased insolation (R=0.35; p=0.000038). Overexpressions of p53 and p16 were significantly more commonly recorded in irritated SK. The tumor proliferative activity by the level of Ki-67 expression was low (3.0 to 11.3%). The largest number (8.5±4.8%) of proliferating cells was recorded in irritated SK (p=0.0000001).

CONCLUSION

The found disorders in the expression of cell-cycle regulatory proteins in SK are suggestive of tumor suppressor activation and keratinocyte senescence. There may be malignant tumor transformation in irritated SK in terms of the significant increase in the expression of p53, p16 in the presence of high cell proliferative activity.

Recent advances in managing and understanding seborrheic keratosis

Seborrheic keratosis (SK) is a common benign epidermal tumor with predominance in adult patients. Whereas common SKs are more frequent in Caucasians, dermatosis papulosa nigra is more prevalent in patients with a Fitzpatrick skin type of at least 3. There seems to be a link between extrinsic skin aging and the occurrence of SK. Mutations of fibroblast growth factor receptor 3 and other signaling molecules are a frequent finding in SK lesions. However, this does not translate into any malignant potential. Viral infections are particularly common in genital lesions, although their pathogenetic relevance for SK is questionable. Different histologic and clinical subtypes have been identified. The great variability of SKs raises some difficulties in diagnosis. Dermoscopy is the preferred non-invasive diagnostic method, in particular to differentiate pigmented SKs from other pigment tumors, including cutaneous melanoma. Eruptive SKs can be a paraneoplastic condition known as the Leser–Trélat sign. New targeted cancer treatments can cause a pseudo-Leser–Trélat sign. The treatment in practice is mainly minor surgery, including cryosurgery, shave excisions, and laser-assisted removal. The medical approaches have only limited effects. Recently, two formulations for topical therapy have been evaluated: a product with 40% hydrogen peroxide (HP40) and an aqueous nitric–zinc complex. Based on clinical trials, HP40 seems to be a promising alternative to surgery, in particular for facial lesions.

Ki-67 and p16 Immunostaining Differentiates Pagetoid Bowen Disease From "Microclonal" Seborrheic Keratosis

OBJECTIVES

We observed keratoses with "clonal" nests present as numerous tiny collections, in which cells in "pagetoid" array are found, a configuration we termed microclonal seborrheic keratosis (MSK). To better distinguish MSK from pagetoid Bowen disease (PBD), we investigated use of immunohistochemical staining.

METHODS

Biopsy specimens of 26 MSKs, 17 PBDs, and 11 borderline cases were reviewed for histopathology and stained with p53, Ki-67, and p16.

RESULTS

High expression of Ki-67 and p16 was observed in 12 (80%) of 15 PBDs and in one (4%) of 23 MSKs. Low expression of p16 and high expression of Ki-67 were observed in 16 (70%) of 23 MSKs and in two (13%) of 15 PBDs. Expression of p16 was elevated in 12 (80%) of 15 PBDs and in three (13%) of 23 MSKs (P < .0001).

CONCLUSIONS

We describe a "microclonal" variant of seborrheic keratosis with morphology sometimes challenging to distinguish from PBD. High expression of p16 and Ki-67 or p16 alone favors the diagnosis of PBD over MSK.

Seborrheic Keratoses - The Most Common Benign Skin Tumor of Humans. Clinical presentation and an update on pathogenesis and treatment options

Seborrheic keratoses (SK) are the most common skin tumour of humanity. The incidence of this purely benign epithelial proliferation is increasing with age and exposure to ultraviolet light. It has a remarkable variability in its clinical presentation raising some differential diagnoses. Recently, oncogenic mutations have been detected involved in the development of SK, which, however, do not bear the risk of malignant transformation. SK may also develop with the use of modern targeted drugs for the treatment of malignancies. The classical treatment options for SK are cryotherapy and curettage. Recently, topical treatment with 40% hydrogen peroxide and the nitric-zinc complex has been investigated. Ablative laser therapy is an effective treatment as well.

Detection of Merkel Cell Polyomavirus in Seborrheic Keratosis

Seborrheic keratosis (SK) is the most common benign cutaneous neoplasm. A subset shows increased p16 expression. Since SK shares several features with verruca vulgaris, e.g., increased p16 expression, human papillomaviruses (HPV) have been suggested as possible causal agents. However, a relevant association could not be established between HPV and SK. In the present study we aimed to investigate the presence of Merkel cell polyomavirus (MCPyV) in relation to p16 expression in SK. P16 expression was investigated using immunohistochemistry (IHC). Presence of MCPyV was assessed in 23 formalin-fixed paraffin-embedded tissue samples of SK by molecular techniques (i.e., PCR and FISH) and IHC. 16/23 SK showed strong to moderate p16 expression. 6/23 of SK were MCPyV positive by PCR which was confirmed by FISH. Of interest, two samples with strong FISH signals also showed MCPyV expression as tested by IHC. Samples with weaker signal intensity were negative in IHC. P16 expression was not associated with the presence of MCPyV. Concluding, the detection of MCPyV DNA by PCR and FISH in SK reflects the widespread prevalence of MCPyV in the skin. However, low detection rates exclude MCPyV as a major pathogenic factor in SK, most likely representing a coincidental infection. P16 IHC does not appear as useful adjunctive surrogate marker for the presence of MCPyV in SK.

Spindle cell squamous cell carcinoma arising in Bowen's disease: Case report and review of the published work

A 79-year-old Japanese woman presented with an ulcerated, brown-red nodule in the center of a sharply demarcated, tan-brown plaque situated on the left side of her right breast. Histologically, the plaque demonstrated an acanthosis with an intraepidermal epithelioma of Borst-Jadassohn. Small oval nests of bland-appearing basophilic cells in the periphery gradually enlarged into nests of various sizes and irregular shapes, composed of densely cohesive, atypical basophilic cells above the central nodule. The atypical keratinocytes shifted to atypical spindle cells beneath the acanthotic epidermis, penetrating deep into the subcutaneous tissue. In addition to vimentin and p63, the spindle cells were positive for several cytokeratin (CK) markers, including AE1/AE3, 34βE12 and CK5/6, which showed more intense signals closer to the epidermis. Basophilic cells in the clonal nests were positive for p63, AE1/AE3, 34βE12 and CK5/6. The MIB-1 index was estimated at approximately 40-50% in both the bland-appearing and the atypical basophilic cells. We describe the first case of spindle cell squamous cell carcinoma arising in an intraepidermal epithelioma expressed by clonal Bowen's disease, which was difficult to differentiate from clonal seborrheic keratosis.

p16 immunostaining in keratinocytic neoplasia in organ transplant recipients: Bowen's disease shows a characteristic pattern

BACKGROUND

For selecting therapy, it is important to distinguish different types of keratinocytic neoplasia. It is sometimes difficult to make histopathologic diagnosis, especially in organ transplant recipients (OTR) who develop numerous lesions.

METHODS

To investigate p16 immunostaining in different types of keratinocytic neoplasia in OTR, we studied 59 actinic keratoses (AK), 51 Bowen' s disease (BD), 63 squamous cell carcinomas (SCC), 16 benign keratotic lesions (BKL) from 31 OTR patients and 25 controls (eczema and psoriasis). Tissue sections were stained for H&E and p16. We scored intensity, proportion and distribution of p16 positive lesional cells.

RESULTS

In 19% of AK, 92% of BD, 35% of SCC and 12% of BKL more than 15% of lesional cells were p16-positive. In 16% of AK, 80% of BD, 18% of SCC and 13% of BKL strong p16 staining was observed. BKL, AK and SCC showed focal and patchy staining, BD showed diffuse pattern with strong staining of all atypical cells. Sparing of the basal layer was predominantly seen in BD. No control specimen showed p16-overexpression.

CONCLUSIONS

p16 immunostaining shows a characteristic pattern in BD, but not in AK, SCC and BKL. It appears useful in recognizing BD, but not in differentiating between other keratinocytic neoplasia.

Human papillomavirus infection and p16 expression in the immunocompetent patients with extragenital/extraungual Bowen's disease

BACKGROUND

The role of human papillomaviruses (HPV) in the development of squamous cell carcinoma (SCC) has been established for anogenital lesions but still remains controversial for carcinomas in other sites. The aim of this study was to determine the α-HPV and β-HPV prevalence and their association with p16 expression, sun exposure, and clinicopathological findings in patients with Bowen's disease (BD).

METHODS

One hundred sixty nine skin biopsy specimens from 157 immunocompetent patients with extragenital/extraungual BD were examined for HPV status and p16 expression. The presence of koilocyte-like changes, solar elastosis and papillomatosis was recorded for each specimen.

RESULTS

BD was diagnosed more often in potentially sun-exposed sites with prevalence 73.6 % and a remarkable predilection for the head and neck region. High risk α-HPV or β-HPV were detected in 34.7 % of lesions and β-HPV infections dominated over α-HPV. Higher prevalence of koilocyte-like changes and papillomatosis was found in HPV-positive specimens but it was not statistically significant. The expression of p16 was detected in 79.8 % of lesions and displayed no correlation with the HPV status. HPV-positivity tended to be detected more often in sun-protected sites. Dual infections by α-HPV/β-HPV genera and mixed α-HPV infections were not detected, while 37.5 % of β-HPV positive specimens were infected by two or more β-HPV genotypes. HPV 9 was significantly associated with mixed β-HPV infections.

CONCLUSIONS

HPV may play an etiological role at least in some SCC in situ arising in extragenital sites. Sunprotected sites may be more dependent on HPV-mediated co-carcinogenesis than sun exposed areas. The presence of the p16-expression, papillomatosis or koilocyte-like change is not a reliable marker of HPV infection in SCC in situ.

Seborrheic keratosis with bowenoid transformation: the immunohistochemical features and its association with human papillomavirus infection

The bowenoid transformation of seborrheic keratosis (SK) has rarely been reported. The purpose of this study is to identify their diagnostic immunohistochemical features and association with human papillomavirus (HPV) infection. Skin biopsy specimens of the phenomenon were retrieved from 2001 to 2010. Benign SK, Bowen disease, bowenoid papulosis, and squamous cell carcinoma were included as controls. All specimens were stained for hematoxylin and eosin, Ki-67, p21, p16, p53, and cyclin D1. Polymerase chain reaction-amplified HPV DNA was analyzed. Seventeen cases of SK with bowenoid transformation were identified. The immunohistochemical pattern of bowenoid transformation was similar to that of Bowen disease and bowenoid papulosis. The malignant cells exhibited increased expressions of p16, p21, and ki-67 and a decreased expression of cyclin D1 (P < 0.01). HPV DNA was detected in 5 cases of bowenoid transformation. In conclusion, a portion of the cases of SK with bowenoid transformation were associated with HPV infection. Selective immunohistochemical stains were helpful in the diagnosis of malignant change in these cases.

Orthokeratotic Bowen disease: a histopathologic, immunohistochemical and molecular study

BACKGROUND

Some examples of Bowen disease lack the characteristic broad parakeratosis making their histopathologic diagnosis particularly difficult in small and incomplete biopsies.

MATERIALS AND METHODS

The archives of our dermatopathology laboratory were searched for cases of Bowen disease with >75% orthokeratosis (orthokeratotic Bowen disease) and classic Bowen disease (>25% parakeratosis). Selected specimens were evaluated histopathologically, using immunohistochemical stains (CK10, CK7, Bcl-2, p16 and Ki-67) and by DNA amplification/sequencing for human papilloma virus (HPV) subtypes.

RESULTS

Among 102 consecutive samples 14 cases of orthokeratotic Bowen disease were identified. In comparison with 24 examples of classic Bowen disease, the orthokeratotic examples occurred more frequently in female and younger patients (p = 0.04 and 0.008, respectively) but shared most of the histopathologic features of classic Bowen disease except a preserved granular layer and relative absence of the eyeliner sign (p < 0.0001 and p = 0.042, respectively). Immunohistochemical staining patterns were similar between the two groups. HPV types 11, 16 and 58 were identified from five cases of orthokeratotic Bowen disease.

CONCLUSION

Orthokeratotic Bowen disease is a distinct variant of squamous cell carcinoma in situ associated with HPV infection in less than half of the cases studied.

Grading of atypia in genital skin lesions: routine microscopic evaluation and use of p16 immunostaining

BACKGROUND

p16 immunostaining has been used to aid and improve the histopathologic evaluation of equivocal cervical lesions with associated low-grade or high-grade dysplasia. However, the utility of p16 immunostaining in the diagnosis of atypical genital skin lesions remains debatable.

METHODS

We conducted a cross-sectional study of genital skin lesions with varying degrees of atypia. Four pathologists assessed lesional atypia and interpreted hematoxylin and eosin (H&E) staining and p16 immunostaining without knowledge of original diagnosis. Our primary outcomes were diagnostic agreement and test performance of p16 immunostaining compared to consensus H&E diagnosis.

RESULTS

Our sample was comprised of 23 cases of atypical genital skin lesions. p16 immunostaining was negative in all cases of reactive atypia (n = 3) and the majority (n = 7 of 8; 88%) of low-grade squamous intraepithelial lesions (LSILs). The majority (n = 10 of 12; 83%) of high-grade squamous intraepithelial lesions (HSIL) were p16 positive. Diagnostic agreement for histopathologic assessment using H&E staining was moderate (kappa = 0.44), while inter-observer agreement of p16 immunostaining was excellent (kappa = 0.87). Compared to consensus diagnosis using H&E staining, p16 immunostaining performed well (sensitivity 83.3%; specificity 90.9%).

CONCLUSIONS

p16 immunostaining may be a useful adjunctive marker for assessing dysplasia in genital skin lesions and increasing diagnostic agreement among pathologists.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.