Keratoacanthoma centrifugum marginatum: a rare atypical variant of keratoacanthoma

Keratoacanthoma centrifugum marginatum (KCM) is an extremely rare variant of keratoacanthoma (KA), with about 30 cases reported since it was first described in 1962. Clinically, KA is an exoendophytic lesion of 10-25 mm with a horn-filled crater that resolves spontaneously within 6 months. In contrast, KCM is characterized by a larger diameter continuous centrifugal spread, concurrent central atrophy and lack of spontaneous remission. Histologically, KCM is similar to KA, with a central keratin-filled crater, overhanging lips of epithelium, a sharp outline between the tumour nests and stroma, and lack of anaplasia and stroma desmoplasia. We describe a 63-year-old agricultural worker with a 9-month history of a multinodular tumour, 70-75 mm in size, on his right hand. The clinical diagnosis of KCM was confirmed by histological examination. Local radiotherapy proved effective, with no recurrence during a 4-year follow-up.     

Keratoacanthoma centrifugum marginatum arising in vitiligo: a case report

Keratoacanthoma centrifugam marginatum (KCM) is a rare variant of the Keratoacanthoma (KA) form of squamous cell carcinoma with only 30 cases reported to date. We report a case of KCM arising in a long-standing vitiligo lesion chronically exposed to sunlight. Over years, the vitiligo lesions gradually evolved into sclerotic plaques and subsequently KCM developed in one of the plaques.     

A case of Ferguson-Smith type multiple keratoacanthomas associated with keratoacanthoma centrifugum marginatum: response to oral acitretin

Keratoacanthoma centrifugum marginatum (KCM) is a rare entity, usually classified as solitary keratoacanthoma (KA). The Ferguson-Smith type is the most common form of multiple KAs. Because development of multiple KAs and KCM in a single patient has rarely been reported, this association presents a therapeutic challenge. We report a 46-year-old man with Ferguson-Smith multiple KAs and KCM, who was successfully treated with acitretin.     

Keratoacanthoma centrifugum marginatum after photodynamic therapy with good response to oral retinoids and topical 5‐fluorouracil

Keratoacanthoma centrifugum marginatum (KCM) is a rare variant of keratoacanthoma (KA), characterized by progressive peripheral growth, and usually devoid of deep invasion. Different systemic (oral retinoids) or topical treatments have been reported, but there is not a well‐defined therapeutic protocol. We report the case of a KCM developing after photodynamic therapy (PDT) on the right leg of a 64‐year‐old woman. It was treated successfully with oral acitretin combined with topical 5‐Fluorouracil + salicylic acid for 5 months. This is the first case of KCM developing after PDT and successfully treated with oral retinoid combined with topical treatment.     

Efficacy of oral retinoids for keratoacanthoma centrifugum marginatum

Keratoacanthoma centrifugum marginatum (KCM) is a rare variant of keratoacanthoma. This condition is difficult to diagnose because of its large size and expansive nature and may be diagnosed as a malignant tumor. There are various treatments such as surgery and oral retinoids; however, limited studies have verified their effectiveness. Here, we report a case of KCM on the anterior chest of a 50‐year‐old woman and evaluate the efficacy of oral retinoids. In this case, oral retinoids were highly effective for KCM treatment. A total of 55 cases of KCM, including 54 previously reported cases, were reviewed, and their clinical characteristics and treatment were examined. In this report, 14 of 16 patients were effectively treated with oral retinoids, resulting in a treatment rate of 87.5%. Furthermore, even low‐to‐medium doses were sufficient for treatment and prevention. KCM can be misdiagnosed as a malignant disease based on its clinical features. Due to its large size and expansive nature, a wide excision may be performed; however, because oral retinoids have a very high response rate, an accurate diagnosis will help avoid an unnecessary wide excision.     

Keratoacanthoma centrifugum marginatum—A rare variant of keratoacanthoma: Case report and literature review

Keratoacanthoma centrifugum marginatum (KCM) is a rare variant of keratoacanthoma and is characterized by progressive peripheral growth with accompanying central healing. Here, we report a case of multiple KCM. A 53-year-old man presented with multiple erythematous papulonodules on both upper limbs and neck for >2 years. His skin lesions enlarged in an annular manner with central residual cribriform scarring that eventually formed confluent plaques (2–8 cm in diameter) with elevated hyperkeratotic borders. Skin biopsy of a developed matured nodule on the right forearm was consistent with that of classical keratoacanthoma. KCM was diagnosed on the basis of clinical and pathological presentation. Low-dose acitretin (0.7 mg/kg/day) was administered and the skin lesions improved significantly within 3 months after the treatment. In this case, we present the clinical and histological features of KCM and discuss the different effective treatment modalities.     

Keratoacanthoma centrifugum marginatum

Keratoacanthoma centrifugum marginatum (KCM) is a rare distinct variant of keratoacanthoma. Based on three personal observations and a review of the literature, the authors describe the clinical and histological features of this neoplasm. Clinically KCM is characterized by the lack of a tendency for spontaneous remission and by continuous centrifugal spread. Histologically there is a subclinical, iceberg-like growth pattern. Like keratoacanthoma, KCM is a highly differentiated, biologically benign, non-metastasizing tumour. The treatment of choice is early excision of the tumour.     

Spontaneous resolution of keratoacanthoma centrifugum marginatum

Keratoacantnoma centrifugum marginatum (KCM) is a rare variant of keratoacantnoma, with > 40 cases reported world wide. Spontaneous resolution of KCM is very rare. To our knowledge, this is the first case of KCM with spontaneous resolution as documented by serial photographs.     

Conditioned medium from cultured human keratinocytes has growth stimulatory properties on different human cell types.

Evidence for growth-stimulatory properties of keratinocyte-conditioned medium (KCM) on human fibroblasts, endothelial cells, keratinocytes, smooth muscle cells, and a mouse fibroblast cell line (3T3 cells) is presented. On human fibroblasts KCM caused an increase of over 400% in DNA synthesis as revealed by 3H-thymidine incorporation and autoradiography. The proliferative effect was comparable to that of platelet-derived growth factor (PDGF), but was not inhibited by PDGF antibodies and exceeded that of transforming growth factor-alpha (TGF-alpha), epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and basic fibroblast growth factor (bFGF). Furthermore, KCM was found to stimulate smooth muscle cells, keratinocytes, and endothelial cells more potently than PDGF, EGF/TGF-alpha, and bFGF, respectively. KCM was also potent in stimulating thymidine incorporation in 3T3 cells, whereas EGF showed a twenty-fold weaker stimulatory effect. Because keratinocytes have been shown to secrete TGF-alpha, which binds to the EGF receptor, binding of factors in KCM to the EGF receptor was assayed. The displacement of radiolabeled EGF by KCM corresponded to a low concentration of EGF (0.5 ng/ml), implying that the growth-stimulatory effect of KCM was not mediated via activation of EGF receptors. Taken together, these results suggest the presence of hitherto unidentified growth-stimulatory factor(s), expressed and secreted by cultured human keratinocytes.     

Multiple keratoacanthoma centrifugum marginatum

Keratoacanthoma centrifugum marginatum (KCM) is a rare variant of keratoacanthoma characterized by a progressive peripheral growth with concomitant central healing. We report here a case of multiple KCM of the lower legs in a 48-year-old man. The lesions had progressively evolved over 3 years. They were multiple asymptomatic and confluent annular plaques of 5 to 20 cm, having papulo-nodular with hyperkeratotic and crusted borders and cicatricial center. Within the centers were numerous firm and pigmented minipapules of 1 to 2 mm. The typical clinical aspect, together with characteristic histological features confirmed the diagnosis of KCM. Herein we will highlight the clinical and histological features of KCM, as well as the different effective treatments. We will also briefly discuss KCM among the other types of keratoacanthomas.     

Keratoacanthoma centrifugum marginatum associated with mechanical trauma: Response to acitretin—A case report and review of the literature

Keratoacanthoma centrifugum marginatum (KCM) is a very rare variant of keratoacanthoma, characterized with progressive centrifugal growth, central healing, and atrophy. Due to its rarity and lack of distinctive histopathological features, KCM often raises diagnostic and therapeutic challenge. We present a case of a 76‐year‐old Caucasian woman with a single large tumor on her right shin that responded to oral retinoids. The patient presented history of local trauma. The tumor developed over the course of 20 months from a scar. To the best of our knowledge, this is the fifth case of KCM associated with mechanical trauma as a possible triggering factor.     

Topical treatment with imiquimod may induce regression of facial keratoacanthoma

Keratoacanthoma (KA) is a rapidly growing tumour histologically resembling squamous cell carcinoma. Although it may regress spontaneously, KA is routinely treated by excision or radiation therapy. Here we report on the successful therapeutic use of imiquimod for the treatment of KA. Four patients with a one to six week history of facial KA were treated with imiquimod cream 5 % every second day for four to 12 weeks. In each patient, KA fully regressed under topical treatment with imiquimod. In three of the patients, KA had disappeared within four to six weeks. In two patients, disappearance was confirmed histologically. No recurrence occurred during a four- to six-month follow-up-period. Our observations indicate that topical immunostimulation with imiquimod may induce or promote immune defence mechanisms leading to KA regression. Imiquimod might therefore prove to be an effective non-invasive treatment modality for KA that warrants more extensive evaluation by clinical studies.     

Intralesional therapy for the treatment of keratoacanthoma

Keratoacanthoma (KA) is a common epidermal tumor that originates from the hair follicle of the skin. It is generally considered as a benign neoplasm, but in rare cases, it can also transform into squamous cell carcinoma. Although surgical excision with a safety margin is considered to be the gold standard treatment for most subtypes of KA, several other treatment options are also available. Intralesional therapy is one of these options, which could be cosmetically and functionally a better alternative to surgical removal, while it provides similar outcomes. It is more effective than topical treatments, yet fewer side effects may be seen than in systemic treatments. Based on the literature, the most commonly used intralesional agent is methotrexate, followed by 5‐fluorouracil and interferon alpha. Regardless of the advantages, which make intralesional therapy a desirable treatment alternative, guidelines for the intralesional treatment of KA are not yet established. A histopathological confirmation before the start of treatment is still recommended to prevent any possible misdiagnosis of KA for SCC. In our present study, we set out to review the current state of the art of the intralesional treatment of KA.     

Keratinocyte-releasable stratifin functions as a potent collagenase-stimulating factor in fibroblasts

Termination of wound healing requires a fine balance between collagen deposition and its hydrolysis. To dissect the underlying control mechanisms for this process, we established a keratinocyte/fibroblast co-culture system and subsequently demonstrated more than a 10-fold increase in collagenase expression in fibroblasts co-cultured with keratinocytes relative to that of control cells. This finding was further confirmed in fibroblasts grown in a keratinocyte/fibroblast collagen-GAG gel. The efficacy of keratinocyte-derived collagenase stimulatory factors on collagenase activity was evaluated, and the results showed that only conditioned medium derived from fibroblasts co-cultured with keratinocytes was able to break down markedly type I collagen to its one-quarter and three-quarter fragments of both alpha (alpha1 and alpha2) and beta (beta1.1 and beta1.2) chains. The results of a dose-response experiment showed that keratinocyte-conditioned medium (KCM) stimulates the expression of collagenase mRNA by dermal fibroblasts in a concentration-dependent fashion. In a similar experiment, the results of a time-response experiment revealed that KCM treatment increases the expression of collagenase mRNA in dermal fibroblasts as early as 6 h and reaches its maximum level within 24-48 h. Considering that this keratinocyte-releasable factor has a potent collagenase stimulatory effect on fibroblasts, which favors the resolution of accumulated type I and type III collagen found in fibrotic tissue, we referred to this protein as a keratinocyte-derived anti-fibrogenic factor (KDAF). In a series of chromatography experiments and a direct trypsin digestion of the proteins and subsequent peptide mapping, a keratinocyte-derived collagenase-stimulating factor turned out to be a releasable form of stratifin, also known as 14-3-3 sigma protein. To validate this finding, stratifin cDNA was cloned into a pGEX-6P-1 expressing vector and more than 50 mg of recombinant stratifin was generated and used to treat fibroblasts with various concentrations for 24 h. The results of northern analysis showed a remarkable dose-response increase in the expression of collagenase mRNA in stratifin-treated fibroblasts relative to that of the control. This finding was consistent with that obtained from collagenase activity assay. In conclusion, we identified a keratinocyte-releasable form of stratifin in KCM that mimics the collagenase stimulatory effect of KCM for dermal fibroblasts. This finding suggests that stratifin is likely to be, at least, one of the KDAFs found in KCM.     

Keratoacanthoma centrifugum marginatum arising from a scar after skin injury.

Among the variants of solitary keratoacanthoma, keratoacanthoma centrifugum marginatum (KCM) is characterized by the lack of a tendency toward spontaneous remission and by continuous centrifugal spread. We describe a case of KCM arising from the scar after an old skin injury. The lesion appeared on the dorsum of the right hand, grew peripherally for 30 months, and became a tumor with a multinodular margin and central atrophy. A biopsy specimen from the edge of the tumor showed features resembling typical solitary keratoacanthoma.     

Intralesional Methotrexate for the Treatment of Keratoacanthoma: Retrospective Study and Review of the Korean Literature

Background

Although intralesional methotrexate (MTX) is an effective, nonsurgical treatment of keratoacanthoma (KA), there have not been many reports of on the MTX treatment for KA in Korea.

Objective

The purpose of this study was to evaluate the clinical efficacy of the intralesional MTX for the treatment of KA in Korean patients.

Methods

We retrospectively studied seven patients with KA who received intralesional injection of MTX in our department. The efficacy was evaluated based on the physician assessment. Our review also included the cases of KA treated with intralesional MTX in Korean patients from the previous reports. We then analyzed the therapeutic regimens in the Korean patients by comparing them with the Caucasian patients.

Results

We identified 11 cases of Korean KA patients treated with an intralesional MTX, including seven from our institution and four from the Korean literature. Ten of the 11 patients (91%) showed a complete resolution with an intralesional MTX. No adverse events were observed during the treatment and the follow-up periods. No recurrence was found during the follow-up. In therapeutic analysis, the Korean patients required 2 to 7 injections (mean 4.6 injections) to achieve a tumor resolution with the mean time to clearing at 7.6 weeks.

Conclusion

Intralesional MTX can be an effective and safe non-operative treatment modality for most Koreans with KA.     

Differentiated keratinocyte-releasable stratifin (14-3-3 sigma) stimulates MMP-1 expression in dermal fibroblasts

Through the use of a keratinocyte/fibroblast co-culture system, we have recently identified a potent keratinocyte-derived anti-fibrogenic factor (KDAF) for dermal fibroblasts. A sequential chromatography of the active fractions of keratinocyte-conditioned medium (KCM) and peptide mapping of the candidate proteins identified KDAF as being the keratinocyte-releasable 14-3-3 sigma (14-3-3sigma) protein, which is also known as stratifin. In this study, we hypothesize that differentiated, but not proliferating, keratinocytes are the primary source of releasable 14-3-3sigma in conditioned medium. To address this hypothesis, in a longitudinal study, keratinocyte differentiation was induced by growing these cells in a medium consisting of 50% keratinocyte serum-free medium (KSFM) and 50% Dulbecco's modified eagle's medium without any additives for up to 20 d. When KCM was collected every other day and added to fibroblasts, the level of matrix metalloproteinase (MMP)-1 mRNA expression was markedly increased in fibroblasts receiving KCM and this increase was even greater in cells receiving conditioned media collected at later time points relative to that of controls. The results of a western blot analysis further showed a marked increase in the expression of 14-3-3sigma protein in keratinocytes grown in test medium from day 4 to day 10. This finding was consistent with the levels of 14-3-3sigma mRNA expression in differentiated keratinocytes. In contrast to a very high level of 14-3-3sigma mRNA expression seen in keratinocytes, fibroblasts that are highly responsive to14-3-3sigma were unable to express this factor. Interestingly, the level of 14-3-3sigma mRNA expression was markedly higher in keratinocytes co-cultured with fibroblasts relative to that of mono-cultured keratinocytes. In conclusion, this study provides evidence that keratinocytes express a high level of 14-3-3sigma at the levels of mRNA and protein. But the releasable form of 14-3-3sigma protein was only found in conditioned medium derived from differentiated keratinocytes. Further, our recently purified recombinant 14-3-3sigma protein mimics the collagenase stimulatory effect of KCM in dermal fibroblasts.     

Keratoacanthoma and other types of squamous cell carcinoma with crateriform architecture: Classification and identification

The terminology and classification of keratoacanthoma (KA) and other types of squamous cell carcinoma (SCC) with crateriform architecture have not been clarified. The study evaluated the clinicopathological features of 41 nodular (exo‐endophytic) SCC lesions with a central keratin‐filled crater, including KA (well‐developed stage). The lesions were histopathologically classified into six categories: (i) KA (well‐developed stage) (27 lesions); (ii) KA‐like SCC (three lesions); (iii) KA with malignant transformation (three lesions); (iv) infundibular SCC (crateriform) (four lesions); (v) crateriform SCC arisen from actinic keratosis (three lesions); and (vi) crateriform Bowen's disease (one lesion). The true characteristics of KA‐like SCC remain unresolved, but there are three possibilities, namely, that it is one step in the evolution of KA, it is a borderline lesion between KA and invasive SCC, or it is one form of “KA with malignant transformation”. KA, KA‐like SCC, KA with malignant transformation and infundibular SCC (crater form) are considered to be hair follicle‐related neoplasms. In contrast, crateriform SCC arisen from actinic keratosis and crateriform Bowen's disease are SCC, which are not related either to the hair follicles or KA. From an etiological standpoint, the presented lesions in these six categories are considered to be mixed up due to the similarity of crateriform architecture between the various types of lesions. However, the information provided in this report is intended to help physicians to make an accurate differential diagnosis of these conditions in clinical practice. The present study provides an opportunity to standardize the terminology for KA and related neoplasms.     

Treatment of Keratoacanthoma with 5% Imiquimod Cream and Review of the Previous Report

Keratoacanthoma (KA) is a benign epidermal tumor, characterized by rapid and abundant growth, a tendency toward spontaneous regression and histopathologic similarity to squamous cell carcinoma (SCC). Because KA can be easily misdiagnosed as SCC, surgery is considered the treatment of choice. Recently, regression of KAs following application of 5% imiquimod cream (Aldara®) has been reported. We present 4 cases of KA treated with topical imiquimod, applied 3 to 4 times a week. Obvious improvement was observed after 4 to 6 weeks of application and the lesions were almost cleared leaving scars after 9 to 11 weeks. These results show that topical imiquimod can be an effective option for the conservative management of KA as previously reported. We also suggest that lesions treated with imiquimod cream should be considered for biopsy to judge histopathological remission after 5 to 8 weeks of application to shorten the duration of the treatment.     

Natural course of keratoacanthoma and related lesions after partial biopsy: Clinical analysis of 66 lesions

There is some confusion regarding the classification of keratoacanthoma (KA) and related lesions that have crateriform architecture. We examined the clinical courses of 66 KA lesions and related lesions after a partial biopsy to clarify the nosological concept of KA. We histopathologically classified these lesions into five types: (i) KA at various stages (53 lesions); (ii) KA‐like squamous cell carcinoma (SCC) (3 lesions); (iii) KA with malignant transformation (3 lesions); (iv) infundibular SCC (5 lesions); and (v) crateriform SCC arising from solar keratosis (2 lesions). We analyzed the clinical course in each group. The regression rate of KA was 98.1% and that of KA‐like SCC/KA with malignant transformation was 33.3%. No regression was observed in either infundibular SCC or crateriform SCC arising from solar keratosis. Thus, KA is a distinct entity that should be distinguished from other types of SCC with crateriform architecture based on the high frequency of regression. The regression rate of 33.3% in KA‐like SCC/KA with malignant transformation indicated that KA lesions with an SCC component still have the potential for regression. However, this result also indicated that KA is biologically unstable, and some KA tend to evolve into conventional SCC with a gradual loss of the capacity for the spontaneous regression. Infundibular SCC and crateriform SCC arising from solar keratosis are fundamentally different from KA, not only according to the histopathological findings but also based on the biological properties.