Oral Papillary Lesions of Acanthosis Nigricans

Introduction:

Acanthosis nigricans appear as velvety hyper-pigmented areas with indistinct borders, commonly found in skin folds such as the back of the neck, axilla, and groin. It is a cutaneous indication of an underlying condition and is often associated with diabetes and insulin resistance. Oral lesions of acanthosis nigricans present as papillary growths in the mouth, similar to those caused by HPV. These lesions are often linked to systemic diseases or malignancies (cancer-causing), and can pose a diagnostic challenge for dental professionals.

What Are the Oral Manifestations of Acanthosis Nigricans?

Acanthosis nigricans (AN) is a rare skin condition that also affects the mucous membranes and has significant health risks. Most individuals with this chronic condition exhibit common oral symptoms. Oral acanthosis nigricans refers to the appearance of lesions on the oral mucosa, which can be either papillomatous (the growth or formation of small, elevated, and often wart-like projections on the skin or mucous membranes) or verrucous (the presence of warts, which are rough, hard, and typically raised growths on the skin or mucous membranes) in nature. These lesions are frequently found on the lips or buccal mucosa, and affected individuals may develop multiple growths in these areas.

There are two main forms of acanthosis nigricans: benign and malignant. Benign (non-cancerous) AN can be caused by hereditary factors, systemic diseases, or drug reactions, whereas malignant AN is often associated with life-threatening cancers like gastric adenocarcinomas. In some cases, malignant acanthosis nigricans can also indicate cancers that can affect multiple organ systems.

What Is the Etiology and Pathogenesis Of Oral Lesions in Acanthosis Nigricans?

Acanthosis nigricans lesions in the oral cavity often serve as significant indicators, that reflect an underlying systemic disease in the body. Several systemic causes and diseases have been associated with Acanthosis nigricans which are as follows:

• Various metabolic disorders can contribute to the development of acanthosis nigricans.

• Certain cancers or malignancies in the body can manifest as acanthosis nigricans lesions in the oral cavity.

• Systemic effects triggered by specific drugs can lead to oral lesions of acanthosis nigricans.

• Disorders related to the endocrine system can be linked to the presence of acanthosis nigricans.

• Certain genetic disorders or conditions may predispose individuals to develop acanthosis nigricans.

• Stress, anxiety, and depression can also be contributing factors to the development of acanthosis nigricans.

• Conditions mediated by the nervous system or those involving interactions between the nervous and immune systems might play a role in the manifestation of acanthosis nigricans.

What Is the Association of Acanthosis Nigricans With Systemic Cancer?

Acanthosis nigricans lesions found in the oral cavity are commonly associated with intra-abdominal malignancies, such as gastric adenocarcinoma (a type of stomach cancer that originates in the glandular cells lining the inner surface of the stomach) which is the most frequent and severe form of cancer observed. When left untreated, acanthosis nigricans lesions tend to progress rapidly, leading to eventual fatalities. Early detection and appropriate intervention are needed to reduce the risks associated with this condition.

What Are the Differential Diagnosis of Acanthosis Nigricans?

In cases of acanthosis nigricans, some patients develop papillary lesions due to underlying cancers, while others specifically exhibit lesions in the mucosa of the lips or oral cavity, such as the buccal mucosa, characterized by hyperkeratosis (increased thickness of the outer layer of the skin) and papillary hyperplasia (growth of one or more nodular lesions). Dentists must establish a definitive diagnosis in patients with acanthosis nigricans. These papillary lesions need to be differentiated from four other oral lesions related to human papillomavirus (HPV), as described by the World Health Organization (WHO).

The differential diagnosis for acanthosis nigricans lesions compared to the listed HPV lesions are as follows:

• Squamous Cell Papillomas Caused by HPV: These are benign growths that develop on the skin or mucous membranes, resulting from HPV infection.

• Condyloma Acuminata Caused by HPV: These are genital warts that occur in the genital and anal areas and are transmitted through sexual contact.

• Verruca Vulgaris Caused by HPV: These are common warts found on the hands, fingers, or other skin areas, caused by specific strains of HPV upon skin contact.

• Multifocal Epithelial Hyperplasia Caused by HPV: Multiple small growths or nodules on the oral mucosa caused by HPV infection are often seen in young individuals.

Do the Papillary Lesions in Acanthosis Nigricans Resemble Those Caused by HPV?

Similarity of papillary lesions in acanthosis nigricans and HPV includes:

• The oral cavity often develops abnormal papillary lesions, with lingual papillae being the common sites.

• These lesions are typically linked to viral infections or complex systemic issues, including diseases like HPV.

• Papillary lesions can arise due to various factors, such as the HPV virus, in a majority of oral cases.

• Acanthosis nigricans patients also frequently develop similar oral papillary lesions associated with underlying systemic diseases, which can be benign or malignant in nature.

• Oral manifestations in acanthosis nigricans are termed the oral papillary group of lesions, that resemble those caused by HPV.

• It is crucial for dental and maxillofacial surgeons to distinguish between acanthosis nigricans lesions and HPV-related lesions.

• Dentists observing these lesions in the oral cavity should consider the possibility of an underlying systemic disease or malignancy.

• Dentists must report their findings to oncologists or general physicians for a comprehensive interdisciplinary approach to management.

What Are the Management Strategies for Acanthosis Nigricans That Can Be Followed by Dental Surgeons?

Addressing Underlying Causes:

• Identifying and eliminating the underlying cause is paramount in treating patients with oral papillary lesions.

• Traumatic factors, such as inappropriate dental prosthesis or sharp tooth tips, should be adjusted, polished, or removed to prevent further irritation of the oral mucosa.

Local Treatment Approaches:

• Local treatments aim to restore aesthetics and functionality in affected individuals.

• Surgical resection, often combined with laser procedures, is a mainline strategy for managing oral papillary lesions in acanthosis nigricans.

• Topical keratolytics like retinoids and Podophyllin are commonly used.

• Eliminating underlying traumatic factors in the oral mucosa can prevent rapid or aggressive growth of papillary lesions in this disease.

Multidisciplinary Approach for Complex Cases:

• In instances where acanthosis nigricans is associated with underlying cancers or systemic diseases, a multidisciplinary approach is crucial.

• Dentists, maxillofacial surgeons, and oncologists must collaborate and correlate their clinical findings to develop comprehensive management strategies for these patients.

Conclusion:

Acanthosis nigricans is a serious condition, which can be potentially fatal if left untreated. Early diagnosis, thorough medical history assessment, and collaboration between dentists and physicians in providing appropriate local or systemic treatments is essential. However, it can be challenging for dental professionals to recognize the diverse oral manifestations of acanthosis nigricans and their possible links to underlying systemic diseases, cancers, or metabolic disorders.