Clear cell acanthoma

Human Papillomavirus-Associated Giant Clear Cell Acanthoma and Squamous Cell Carcinoma: A Rare Case Report and Literature Review

Clear cell acanthoma (CCA) and squamous cell carcinoma (SCC) represent distinct entities within dermatological oncology, each posing unique diagnostic and therapeutic challenges. CCA is a rare, benign epidermal growth, often not associated with human papillomavirus (HPV) infection, whereas SCC, a more aggressive form of skin cancer, has been linked to both ultraviolet (UV) exposure and HPV. Understanding the co-occurrence of these conditions in a single patient can enhance diagnostic accuracy and therapeutic outcomes. We report a 64-year-old male who underwent an operation for a verruciform lesion in the right groin, which was diagnosed as HPV-positive CCA alongside keratinised SCC. A literature search across January 2024 revealed limited evidence directly linking HPV to CCA, suggesting a need for further investigation. The speculative association between HPV and CCA warrants deeper exploration, especially considering the potential for HPV to contribute to lesion development through indirect mechanisms. The coexistence of CCA and SCC in an elderly patient presents a unique clinical scenario. This emphasises the need for vigilant diagnosis and tailored treatment strategies, highlighting the gap in understanding the pathogenesis of CCA, particularly its potential association with HPV. Further research is crucial for elucidating the complex interactions governing these conditions and for developing targeted interventions.

Clear Cell Acanthoma: A Series of 70 Cases

BACKGROUND AND OBJECTIVE

Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting.

MATERIAL AND METHODS

Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment.

RESULTS

Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5) mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists.

CONCLUSIONS

CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy.

[Translated article] Clear Cell Acanthoma: A Series of 70 Cases

BACKGROUND AND OBJECTIVE

Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting.

MATERIAL AND METHODS

Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment.

RESULTS

Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5)mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists.

CONCLUSIONS

CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy.

Multiple Eruptive Clear Cell Acanthomas Successfully Treated with CO2 Laser Ablation

Clear cell acanthoma (CCA) is a rare, benign epidermal lesion of clear glycogen-containing keratinocytes. The exact etiology is unknown. Although CCA usually appear as solitary lesions, cases of multiple CCAs have also been described. The rare eruptive CCA variant describes cases with more than 30 lesions.Current therapeutic evidence for the management of multiple CCAs is limited. CO2 laser remains the most widely used laser in clinical practice. However, literature describing its effectiveness on CCA is sparse, and previous reports have described its use for a maximum of three lesions. To our knowledge, this is the first report of successful CO2 laser treatment of the multiple eruptive CCA variant with an excellent cosmetic outcome.Our case adds to the evidence that CO2 laser is an effective treatment for this condition. Particularly in those patients with refractory or multiple eruptive CCAs, or for those who may not tolerate repeated courses of cryotherapy, or who are concerned about scarring and cosmetic outcome.

Non-Invasive Diagnosis of a Facial Tumor Using Dermoscopy and Successful Treatment with 595 nm Pulsed Dye Laser

Clear cell acanthoma (CCA) is an uncommon, benign epithelial tumor presenting as a well-defined, slow-growing solitary nodule. The diagnosis of CCA is usually based on clinical and histopathological evaluation of the tumor. However, when such type of benign tumor occurs on an exposed area, a biopsy is not always the best diagnostic option since it may leave scar. The recent advent of dermoscopy has offered an accurate and non-invasive method to diagnose CCA without resorting to skin biopsy. A 40-year-old male presented with a shiny, erythematous-to-brown, flattened nodule on the left cheek. Dermoscopic examination revealed a 'string of pearls' vascular pattern, a characteristic dermoscopic feature of CCA. Under the clinical and dermoscopic impression of CCA, a 595 nm pulsed dye laser (PDL) therapy targeting the vascular tissue in the superficial dermis of the lesion was chosen for a minimally invasive treatment. After repeated sessions of PDL, an optimal cosmetic outcome was achieved and no recurrence was recorded during the follow-up period. Herein, we report a case of presumed CCA which was successfully diagnosed and treated by utilizing non-invasive modalities.

Clear cell acanthoma

Clear cell acanthoma is a rarely diagnosed tumor with variable clinical morphology that is usually only recognized by its histopathological features. The primary lesion is a red papule a few millimeters in diameter that often occurs as a single lesion on the lower extremities. In dermoscopy, resemblance of the vessels to a string of pearls is a largely specific finding of clear cell acanthoma. In contrast to the initially uncharacteristic clinical findings, histopathology of clear cell acanthomas is characterized by a typical compact, well-demarcated acanthosis consisting of pale-staining, PAS-reactive keratinocytes. As etiology and pathogenesis are both unclear, nosology of clear cell acanthoma is also controversial, with an ongoing debate as to its classification as cutaneous neoplasia or reactive inflammatory dermatosis.

Clear Cell Acanthoma: A Review of Clinical and Histologic Variants

Degos and Civatte first described clear cell acanthoma (CCA) in 1962 and later in a review article found that, in most instances, the lesion was a solitary red-brown dome-shaped papule that involved the distal lower extremity. The first morphologic variant of CCA was reported as a "giant form of the acanthoma of Degos" which measured 45 × 40 mm, about twice the size of the largest CCA documented earlier. Since then, many variants of CCA have been described, including polypoid, pigmented and atypical. Herein, we describe a new variant of CCA and add another example of the polypoid variant to the literature. The new variant exhibits cellular features of trichilemmoma but architecturally differs from it. We also attempt to broaden the list of CCA variants summarized by Tempark and Shwayder by adding ours and a few more examples of CCA. The new variants of CCA include verrucous, linear, subungual and trichilemmal.

Pale (Clear) Cell Acanthoma of the Palate

Clear cell acanthoma (CCA), also known as pale cell acanthoma, represents a rare benign epidermal tumor with strong predilection for the lower extremities of middle-aged individuals and no frank gender preference. The etiology of CCA is poorly understood, although a localized psoriasiform reaction is favored. Herein, we report on the clinicopathologic and immunohistochemical features, and HPV status of an apparent example of oral CCA. A 58-year-old female presented with a well-circumscribed, asymptomatic, exophytic, sessile and erythematous nodule of the right hard palate, measuring 0.7 cm in greatest dimension. Microscopically, the lesion featured parakeratosis and acanthosis with neutrophilic microabscesses and broad elongated rete pegs. In areas, spinous epithelial cells exhibited pale or clear cytoplasm without nuclear pleomorphism, mitoses or cytologic atypia. The supporting connective tissue revealed mild chronic inflammation with few scattered neutrophils and numerous capillary vessels. PAS histochemical stain with and without diastase disclosed the presence of cytoplasmic glycogen in the pale cells. The majority of glycogen-rich epithelial cells stained strongly for EMA and were negative for D2-40. Ki-67 immunostaining was confined only to the basal cell layer of the epithelium. A diagnosis of CCA was rendered. The lesion was negative for human papillomavirus (HPV) infection, as assessed by HPV-DNA PCR using the MY09/11 primers for the L1 conserved region, thus HPV infection does not appear to contribute to the pathogenesis of oral CCA. In conclusion, we report an intraoral example of CCA in order to raise awareness about this entity.

Clear Cell Acanthoma with Atypical Location -Case Report and Literature Review

Clear cell acanthoma is an uncommon, benign lesion, usually present in middle-aged and elderly patients. It looks like an erythematous papule, solitary, with squama at the periphery, regularly located on the lower limbs. We present the case of an 80-year-old female, who was admitted in the Dermatology Clinic of Craiova for an infiltrative plaque, erythematous-squamous-crusty, well delimited, with sizes 1,2/1,5cm, polycyclic shape, located in the right groin. The onset of the condition was 7-8 years ago, with slow growth in size. The excision of the lesion was performed and the histopathological examination confirmed the diagnosis of clear cell acanthoma. Our case is atypical by location. Because clear cell acanthoma is difficult to be clinically diagnosed, with a wide range of lesions that make a differential diagnosis, we highlight the importance of histopathological examination for a positive diagnosis. The treatment depends on the type of lesion and on the patient's preference, usually consisting in surgical excision.

Clear cell proliferations of the skin

Clear cell proliferations of the skin consist of a diverse group of lesions characterized by the presence of cells with abundant clear cytoplasm. They may arise from primary, metastatic, or non-neoplastic origins, with their distinctive cytoplasmic clearing attributable to causes ranging from artifact to accumulation of materials such as glycogen, mucin, or lipids. Despite the heterogeneity of these lesions, their distinguishing characteristics may be subtle, especially at high power. As such, histologic diagnosis can be challenging, and proper consideration relies on an understanding of the scope of possible origins, etiologies, and key immunohistochemical staining patterns of the various entities. This review categorizes cutaneous clear cell neoplasms by histogenesis, and offers differential diagnostic strategies to aid in their clinicopathologic evaluation.

Topical calcipotriol as a new therapeutic option for the treatment of clear cell acanthoma

Although uncommonly diagnosed, clear cell acanthoma represents an original source of speculative interest for dermatologists. Due to its clinical variability, it is often only recognized accidentally after histology. Dermoscopy has improved the reliability of clinical diagnosis of typical clear cell acanthoma thanks to the vascular pinpoint pattern and desquamative, peripheral collarette. Generally, therapy of clear cell acanthoma is oriented towards ablative solutions, such as surgery or cryotherapy. We propose a conservative therapy, based on the application of topical calcipotriol, which has produced complete regression after 2 months and no relapse one year after the end of treatment. A dermatoscope monitored all changes of clear cell acanthoma, showing its utility not only in diagnosis but also in therapeutic follow-up. This new therapeutic approach should support an inflammatory etiology of clear cell acanthoma, although further observations are needed to confirm this.