T-lymphocyte profiles differ between keratoacanthomas and invasive squamous cell carcinomas of the human skin.

BACKGROUND: T-lymphocytes are involved in tumor progression and regression. Actinic keratoses (AK) are atypical proliferations of keratinocytes of the skin. Some AK progress into invasive cutaneous squamous cell carcinomas (cSCC). Keratoacanthomas (KA) are either classified as a cSCC subtype or a benign tumor with histologic resemblance to well-differentiated cSCC as it is supposed to regress spontaneously. In contrast, cSCC represent malignant tumors that may metastasize. OBJECTIVES: To compare the T-lymphocyte profiles of AK, KA and cSCC in relation to PD-L1 expression. METHODS: Tissue micro-arrays of 103 cases of AK, 43 cases of KA and 106 cases of cSCC were stained by immunohistochemistry for E-cadherin, CD3, CD4, CD8, FOXp3, and the receptor-ligand pair PD-1/PD-L1. Immunohistological scores were computationally determined to assess PD-L1 expression as well as the expression profiles of T-lymphocytes. RESULTS: AK had lower numbers of CD3+ and PD-1+ cells compared to KA and lower numbers of CD3+, CD8+ and PD-1+ cells in comparison with cSCC. KA showed significantly higher numbers of CD4+ and FOXp3+ cells as well as lower numbers of CD8+ cells in comparison with invasive cSCC. cSCC expressed significantly more PD-L1 in comparison with AK and KA. Among cSCC PD-L1 expression was higher in moderately and poorly-differentiated cSCC than in well-differentiated cSCC. Increased PD-L1 expression also correlated with increased numbers of CD4+, CD8+ and FOXp3+ cells in cSCC. CONCLUSIONS: Tumor-associated T-lymphocyte infiltrates showed significant differences between AK, KA and invasive cSCC. PD-L1 expression correlated with invasion of T-cell infiltrates in invasive cSCC.

Cutaneous intravascular CD30+ T-cell pseudolymphoma occurring in a regressing keratoacanthoma.

Cutaneous intravascular CD30+ pseudolymphoma is an uncommon incidental finding that may mimic intravascular or angiotropic lymphoma. We describe a 78-year-old female with a traumatized regressing keratoacanthoma on her left cheek. A shave biopsy revealed intravascular staining of atypical lymphocytes positive for CD45, CD3 and CD30. Clinical exam revealed no other evidence of lymphoma, the patient denied constitutional symptoms, and routine blood work was normal. The patient is healthy and doing well 28 months after her first visit. CD30+ pseudolymphoma should be distinguished from malignant intravascular lymphoproliferative disorders.

Keratoacanthoma in the inferior lip of an immunosuppressed patient. A case report.

Keratoacanthoma is a lesion typical crater, symmetrical, rounded, rapid growth with high potential for self-involution. The lesions may be multiple, disseminated and associated with some syndromes. The etiology of keratoacanthoma is not known, but it is often observed in patients chronically exposed to sun. Histopathological features of keratoacanthoma may resemble those of a well differentiated squamous cell carcinoma. The hallmark of the disease is spontaneous resolution after an intermediary stationary stage. The majority of the cases is treated by surgical excision. For this reason, very few cases have been documented until resolution, which constitutes the gold standard for this clinic diagnosis. The aim of this article is to report a case of keratoacanthoma in the inferior lip of an immunosuppressed patient.

Comparison of immunosuppressive and immunomodulatory cells in keratoacanthoma and cutaneous squamous cell carcinoma.

An imbalance of immunosuppressive and immunomodulatory cells plays an important role in inhibiting the anti-tumour immune response in a tumour-bearing host. Among such cells, regulatory T cells (Tregs), together with immunosuppressive macrophages, such as CD163+ M2 macrophages, play roles in maintaining the tumour microenvironment. In contrast, interleukin-27 (IL-27) induces STAT1 and STAT3 activation, thus resulting in the enhancement of naive CD4 T-cell proliferation, the promotion of early Th1 differentiation, and the induction of the anti-tumour immune response. The purpose of this study was to investigate the involvement of immunosuppressive cells, such as Tregs and CD163+ macrophages, as well as immunomodulatory cells (i.e. IL-27-producing cells) in keratoacanthoma (KA) and invasive squamous cell carcinoma (SCC). We also examined the presence of CD3+ Foxp3+ Tregs cells in lesional skin from 10 patients with KA and 18 patients with SCC. Increased numbers of CD3+ Foxp3+ Tregs were observed in SCC compared with KA. In parallel with Tregs, higher numbers of CD163+ macrophages and MMP-9+ cells were detected only in SCC. In contrast, IL-27-producing cells were increased only in KA. In addition, the expression of pSTAT1 on tumour cells was observed only in KA. These findings suggest that the induction of immunosuppressive and immunomodulatory cells differs between KA and SCC.

Stromal CD10 expression, as well as increased dermal macrophages and decreased Langerhans cells, are associated with malignant transformation of keratinocytes.

BACKGROUND: It has become evident that resident stromal cells, such as fibroblasts and inflammatory cells, are involved in the metastatic process, including proliferation or migration of malignant neoplasms. We analyzed CD10+ stromal cells, dermal macrophages and Langerhans cells (LCs) in skin tumors. METHODS: Immunohistological staining was performed with markers for macrophages (CD68), LC (CD1a), stromal fibroblasts (CD10) and cell proliferation (Ki67) in 12 normal skins (NSs) and 15 cases each of seborrheic keratosis (SK), actinic keratosis (AK), keratoacanthoma (KA), Bowen's disease (BD) and squamous cell carcinoma (SCC). RESULTS: All SCCs showed weak to strong stromal CD10 expression, while all NS, SK and AK were negative. Weak CD10 expression was observed in only 2 of 15 samples in both BD and KA. The number of CD68+ cells and Ki67 labeling index in SCC and BD were significantly higher than that in KA, AK and SK. In contrast, the number of LC was lower in SCC and BD. The stromal CD10 expression was significantly correlated with the Ki67 labeling indices and CD68+ cells and negatively correlated with decreased LC. CONCLUSIONS: The stromal CD10 expression is associated with malignant transformation of keratinocytes together with infiltration of dermal macrophages and loss of LC.

Imiquimod for restoring local immunity in a renal transplant patient with persistent keratoacanthoma.

Keratoacanthoma (KA), a cutaneous neoplasm histologically resembling squamous cell carcinoma, is characterized by rapid growth and common spontaneous regression. The regression depends on an individual's immune response. We are reporting a case of a 53-year-old man who presented with an ulcerated tumor, which had arisen as a nodular lesion 9 months earlier. This was localized on the the left thumb. The patient had undergone a kidney transplant after severe glomerulonephritis. Following the operation, he was treated with systemic immunosuppressive drugs and developed multiple non-melanoma skin cancers. The histology examination of biopsy specimens was consistent with keratoacanthoma and showed low-density chronic inflammatory cells. Our patient refused surgical excision, so we prescribed imiquimod 5 percent cream once daily for 5 days a week. After 6 weeks of treatment the lesion had regressed completely, yielding an excellent cosmetic result. Continued resolution was documented 3 years after treatment. The patient had no signs of graft rejection related to the imiquimod treatment.

CD30+ cell population in common keratoacanthomas: a study of 21 cases.

Many examples of epidermal pseudocarcinomatous proliferations associated to CD30+ lymphoid infiltrates are described in literature. Most of them have been interpreted as epidermal proliferations secondary to the lymphoid infiltrate. In this study, our purpose was to investigate the CD30+ cell population in keratoacanthomas of patients with no other cutaneous or hematological conditions. We randomly selected 21 cases of KA from our archives and performed an immunohistochemical study for CD30 in all of them. The quantity of CD30+ cells was graded according to a 5-tier system (from non-existent to evidence of groups of three or more CD30+ cells each: 0-4). In four cases, the inflammatory infiltrate could not be studied, since the lesions had been enucleated. From the other 17 cases, in 94.12% of them, the infiltrate was graded as 3 or 4. Only one case was graded as 1, and interestingly, this case corresponded to a keratoacanthoma in regression. We also studied the percentage of CD30+ cells in the infiltrate in each case, obtaining a mean of 2.89%. We conclude that CD30+ cells are a common component of the inflammatory infiltrate of normal keratoacanthoma. We also wonder if the cases described as either lymphomas or lymphomatoid papulosis with keratoacanthomatous changes are nothing more but simple keratoacanthomas. Lastly, we see this CD30+ infiltrate as a source of investigation to understand why keratoacanthomas spontaneously regress, instead of progressing to a metastasizing squamous cell carcinoma.

Non-familial multiple keratoacanthomas in a 70 year-old long-term non-progressor HIV-seropositive man.

We describe here multiple keratoacanthomas in an Human Immunodeficiency Virus (HIV)-seropositive 70 year-old man. The patient had multiple epithelial tumors of the skin showing rapid growth, histopathological features of a keratoacanthoma and a conspicuous tendency toward spontaneous remission. A diagnosis of nonfamilial multiple keratoacanthoma was established. The patient had a CD4 count of 633 cells/microL. The HIV disease in our patient was of a nonprogressive nature with CCR5-positive T cells.

Expression of apoptotic and cell proliferation regulatory proteins in keratoacanthomas and squamous cell carcinomas of the skin.

The aim of this study was to investigate the expression of p53, caspase-3, bcl-2, MIB-1, and PCNA to validate more objective methods to differentiate squamous cell carcinoma and keratoacanthoma, as well as to understand their pathogenesis with accuracy. A total of 52 cases of histopathologically diagnosed keratoacanthoma in the proliferative stage and 56 cases of well-differentiated squamous cell carcinoma were selected in this study. The expression was evaluated by means of immunohistochemistry. Bcl-2 immunoreactivity was weak or absent in the majority of cases, either in squamous cell carcinoma or in keratoacanthoma. PCNA-positive cells did not show differences between two lesions evaluated. On the other hand, MIB-1 was statistically significant (p<0.05) between squamous cell carcinomas and keratoacanthomas. Moreover, p53 and caspase-3 were overexpressed in squamous cell carcinomas. Together, these results suggest that the biological behavior of the well-differentiated squamous cell carcinomas of the skin may be associated with cellular proliferation and/or deregulation of cell death, indicated by increased expression of the MIB-1 and apoptotic proteins p53 and caspase-3, respectively.

CD30+ cells in regressing keratoacanthoma and in non-keratoacanthomatous squamous cell carcinoma.

In a previous report, we demonstrated how a percentage of CD30+ cells was nearly constant in the inflammatory infiltrate that accompanies keratoacanthoma (KA), but we saw a lack of CD30 cells when KA was regressing. In the current study we investigated the presence of CD30+ cells in the inflammatory infiltrate of regressing KA as well as in well-differentiated squamous cell carcinomas of non-keratoacanthomatous type. We examined 80 keratoacanthomas from our archives, and selected those with the pattern of advanced regression. We also examined 14 well-differentiated non-KA type SCCs from our archives. In all the cases, we performed a immunohistochemical study for CD30. Of the 80 KAs, 6 cases (7.5%) showed the pattern of regression. While the mean of the percentages of CD30+ cells in the infiltrate was 0.58 for the regressing KAs, it was 1.77 for SCCs. While cells with the paranuclear-dot pattern of immunostaining plus membranous pattern of immunostaining could be easily found in SCC cases, cells only with membranous expression of the marker were the rule in KA. We conclude that CD30 positive cells might play a role in KA regression (Tab. 2, Fig. 4, Ref. 24).

Silver-stained organizer regions and immunoglobulins in cutaneous keratoacanthomas and squamous cell carcinomas.

The aim of this study was to investigate the biologic activity of epidermal cells in keratoacanthomas (KAs) and squamous cell carcinomas (SCCs) by counting the number of silver-stained nucleolar organizer regions (AgNORs), to estimate the quantity of Ig-producing cells and the inflammatory cellular infiltrate (ICI), and to make a comparative evaluation. Thirty KAs (10 at growth stage, 10 at mature stage, and 10 at involution stage) and 28 SCCs (nine well differentiated-Grade 1 (G1), seven moderately differentiated-Grade 2 (G2), five poorly differentiated-Grade 3 (G3), and seven pseudoadenoid) were investigated. The KAs examined had a mean number of 1.727 AgNORs (S.D. 0.232), and IgG predominated in most cases. IgG and IgE increase at the involution, IgA remains at almost the same level, and IgM decreases during the maturity stage. The SCCs examined had a mean number of 2.105 AgNORs (S.D. 0.446). IgG predominated and gradually increased in proportion to the degree of malignancy. There is a significant difference in the number of AgNORs and the proportion of Ig subclasses in contrast to the cellular infiltrate among the three stages of KA. In SCCs, the number of AgNORs and the percentage of Igs and ICI increased gradually in proportion to the degree of malignancy.

Possible key role of granzyme B in keratoacanthoma regression.

It is still controversial whether keratoacanthoma is to be considered as a well differentiated variant of squamous cell-carcinoma or a separate entity. As opposed to malignant potential of squamous cell-carcinoma, keratoacanthoma is characterized by a spontaneous regression. However, in some cases, otherwise typical keratoacanthoma can behave aggressively showing the signs of perineural and perivascular invasion and metastases in regional lymph nodes. The most important feature that separates these two closely related entities is a tendency of keratoacanthoma to regress. Causes and detailed mechanism of this regression are still not completely elucidated. Within the past few years, it has become evident that the molecular events regulating cell survival and apoptosis are important contributors to the overall kinetics of benign and malignant cell growth. Immunological mechanisms have been implicated in a phenomenon of spontaneous tumor regression. Recent studies suggested that the tumor regression is dependent mainly on the immune response mediated by cytotoxic T lymphocytes (CD8+), together with helper T cells (CD4+). Cytotoxic T lymphocytes can kill tumor cells and mediate tumor regression in vivo through two distinct molecular mechanisms: Fas/Fas ligand and granzyme B/perforin mediated pathways. Tumor cells are capable of developing different escape mechanisms in order to overcome their sensitivity to apoptotic signals. However, granzyme B, contained in cytolytic granules released upon target cell recognition, can also cause tumor cell death and consequently tumor regression by direct damage to non-nuclear structures through a caspase-independent pathway. Therefore, we propose a key role of plasticity in the granzyme B mediated cell death pathway in the killing of changed tumor cells, resulting in keratoacanthoma regression through apoptosis or direct damage of tumor cells. On the other hand, insufficient activation of cytotoxic T lymphocytes and decreased release or activity of granzyme B could be responsible for squamous cell-carcinoma progression and occasional aggressive behavior in keratoacanthomas. As a first step in confirming or refuting our hypothesis, we suggest a thorough immunohistochemical study of the presence of granzyme B and its activity in keratoacanthoma and squamous cell-carcinoma samples. To our knowledge, no such study has been performed so far.

Acute development of multiple keratoacanthomas and squamous cell carcinomas after treatment with infliximab.

Infliximab, a chimeric mouse-human monoclonal antibody, blocks the action of tumor necrosis factor-alpha and is a highly effective treatment for several inflammatory disorders, including inflammatory bowel disease and rheumatoid arthritis. Although safety data are encouraging, immunosuppressive sequelae may result. We report the acute development of multiple squamous cell carcinomas and keratoacanthomas in a patient receiving infliximab for rheumatoid arthritis.

The immunopathology of regression in benign lichenoid keratosis, keratoacanthoma and halo nevus.

BACKGROUND: Regression is a phenomenon present in a variety of cutaneous lesions. It is likely that similar immunologic mechanisms explain the phenomenon of spontaneous regression occurring in the various lesions. METHODS: Twenty-seven specimens, nine each of halo nevus, keratoacanthoma, and benign lichenoid keratosis, including three examples each of predominantly early, mid, and late regression were examined with antibodies to HLA-II, CD1a, CD3, CD4, CD8, CD20, CD34, CD56, and CD68. RESULTS: Epidermotropism of inflammatory cells, including CD1a positive, CD68 positive, CD3 positive, and CD8 positive cells, was present in benign lichenoid keratosis and keratoacanthoma, but not in halo nevus. In halo nevus, the nests of halo nevus cells tended to be infiltrated by CD1a positive, CD68 positive, CD3 positive, and CD8 positive cells. The blood vessels exhibited endothelial cell swelling with luminal narrowing and disruption within the dermis of all lesions. The CD1a positive cells were increased in number in lesional epidermis except in keratoacanthoma lesions where the density of CD1a positive cells was increased in the epithelial lip, but decreased within the epithelial portion of the keratoacanthoma proper. Conversely, the CD8 positive cells were scarce in the dermis below the epithelial lip of the keratoacanthoma, but increased in the dermis of the neoplastic epithelium. CD1a positive cells were also seen throughout the dermal portion of the lesion, particularly at the lesion base. In halo nevus, the CD1a positive cells and CD68 positive cells within the lesions were larger than those in non-lesional skin, indicating activation. The composition of the inflammatory infiltrate varied within each lesion type according to stage of regression, but T-lymphocytes predominated. CONCLUSION: Cytotoxic T-cells may be the final common denominator of regression in benign lichenoid keratosis, keratoacanthoma, and halo nevus. In halo nevus, cytotoxic T-cells may play the predominant role in regression. In keratoacanthoma and benign lichenoid keratosis, cytotoxic T-cells play a pivotal role, but additional mechanisms may also be involved in the phenomenon of regression. Benign lichenoid keratoses progress through stages of regression accompanied by varying proportions of inflammatory cells, including CD3, CD4, and CD8 positive T-lymphocytes, natural killer cells, macrophages and Langerhans cells.

Identification of human papillomavirus in keratoacanthomas.

BACKGROUND: Keratoacanthomas are benign, clinically distinct skin tumors that may infiltrate and show cellular atypia. A viral etiology has been suggested, and the aim was to search for human papillomavirus (HPV) in keratoacanthomas. METHODS: From 21 immunosuppressed organ transplant recipients and 11 non-immunosuppressed patients, 72 fresh biopsies with diagnosis of keratoacanthomas were analyzed. For detection of cutaneous and genital HPV DNA, single-tube nested "hanging droplet" polymerase chain reaction (PCR) and another PCR (GP5+ and 6+) were used, respectively. RESULTS: Among 21 immunosuppressed patients, 71% (15/21) harbored HPV DNA at least in one sample. Of the keratoacanthoma lesions, 55% (33/60) were HPV DNA positive. Fourteen samples from eight immunosuppressed patients contained HPV types 5, 9, 10, 14, 19, 20, 21, 38, 49, 80, putative HPV types as HPVvs20-4, HPVvs75, and HPVvs92 and FA16.1, FA23.2, FA37, FA75, and FA81. Among 11 non-immunosuppressed patients, 36% (4/11) harbored HPV DNA at least in one sample, and 33% (4/12) of their keratoacanthomas were HPV DNA positive. In total, HPV DNA was detected in 51% (37/72) of the keratoacanthomas. CONCLUSIONS: By the use of PCR, cutaneous HPV DNA was detected in 51% (37/72) of the keratoacanthomas. No predominating HPV type or genital HPV type was identified. The role of HPV in keratoacanthomas remains thus elusive.

Solitary keratoacanthomas in immunocompetent patients: no detection of papillomavirus DNA by polymerase chain reaction.

The aetiology of keratoacanthoma (Ka) is unknown, but human papillomavirus (HPV) has been implicated in the pathogenesis of this lesion. To evaluate the role of HPV in the development of KA in the general population, 20 tissue specimens were analysed by polymerase chain reaction (PCR). To include a broad range of both cutaneous and mucosal HPV types, PCR was performed with two sets of degenerate primers. No HPV-DNA sequences were detected in any lesions analysed. These results do not support the hypothesis that HPV is involved in the etiology and pathogenesis of the KA in immunocompetent patients.