Heck’s Disease of Oral Cavity - An Overview

Introduction

Human papillomavirus types 13 and 32 (HPV13 and HPV32) are the cause of the uncommon and benign oral condition known as focal epithelial hyperplasia (FEH), often referred to as Heck’s disease or multifocal epithelial hyperplasia (MEH). It manifests as a series of tiny (between 0.2 and 3 centimeters, or 0.07874 inches and 1.1811 inches), soft, raised lesions in the mouth that are whitish or the same color as the mucosa. When the mucosa is stretched, the lesions vanish.

Treatment might be required if the lesions become large or are in troublesome areas, although they are frequently asymptomatic. People of all ages are affected by FEH, with a higher frequency in younger individuals (average age 23.1 years) and a slightly higher incidence in females than males (ratio 3:4). Clinical and histological examinations are used to make the diagnosis; biopsies reveal tiny, flat, squamous papillomas with distinct cellular alterations but no indications of malignancy. Treatment for FEH lesions is only required if they cause discomfort or other problems. These lesions are often not life-threatening or malignant.

What Are the Incidence, Location, and Demographics of Heck's Disease?

Incidence and Location:

• It usually affects the inside of the lips, tongue, and cheeks.

• Extremely uncommon generally but more common in some ethnic groups.

Morbidity and Mortality:

• Benign growths that tend to go away on their own.

• They have no chance of developing into cancer.

Gender, Race, and Age Distribution:

• It is found in some ethnic groups more frequently in females than in males (2:1).

• Initially noted in American Indians and Inuits, it is now seen in a number of ethnic groups.

• It mainly affects kids; however, it can also strike HIV (human immunodeficiency virus) - positive adults on HAART (highly active antiretroviral therapy) medication.

How Do HPV13 and HPV32 Relate to Heck’s Disease and Cancer Risk?

The two low-risk, non-cancerous HPV strains most frequently detected in FEH are HPV13 and HPV32. There have also been reports of HPV 6, 11, 16, 18, and several other kinds in FEH cases. For instance, it was discovered that a 56-year-old woman's FEH lesion had HPV90, another low-risk variety. This was the first occasion that FEH and this specific strain of HPV were connected.

Although there have been a few Heck’s disease instances with high-risk HPV strains, no reports of these cases developing malignancy have been made. Research has demonstrated that HPV32 does not result in cancers, even though its genetic makeup is more similar to that of the high-risk HPV16 than the low-risk HPV13. A persistent HPV16 infection may cause serious illness, according to research from Finland, although it is unknown how Heck’s disease lesions containing high-risk HPV strains may impact cancer risk.

A procedure known as superinfection exclusion can stop further infections when several HPV types are present in the same location. This implies that a cell infected with one form of HPV may prevent the infection of future cells with that kind. Superinfection exclusion may prevent infections with high-risk HPV types like HPV16 and HPV18, even if FEH lesions have been reported to include numerous HPV types.

Research has demonstrated that in laboratory conditions, pre-existing HPV16 infections can prevent secondary HPV18 infections, yet cervical cancer cells have been observed to harbor both HPV16 and HPV18 instances. All things considered, current HPV infections may provide some defense against subsequent infections with closely related HPV strains.

How Is Heck's Disease Transmitted and Diagnosed, and How Are HPV Types Detected?

Household Transmission: Since HPV13 has been detected in the saliva of infected people, it is believed that FEH is transferred by saliva. Over 70 percent of respondents (average age 13.2 years; ages four to 73) to a poll conducted in a village in Mexico said they shared kitchen utensils and toothbrushes and had unhygienic living conditions.

Diagnosis: HPV involvement is infrequently tested for FEH; instead, the condition is often diagnosed based on clinical presentation and biopsy results. Important characteristics include ballooning degeneration, thicker rete ridges, mitosoid structures (individual keratinocytes that resemble mitotic figures due to nuclear fragmentation), koilocytosis (cells with transparent cytoplasm), and epithelial hyperplasia. In a study of 52 individuals, mitosoid bodies were frequently observed; nonetheless, their presence is not diagnostically significant.

HPV Detection: Pan-anti-HPV antibodies are occasionally employed in immunohistochemistry; however, this method is not specific to any one kind of HPV. Because these are low-risk viruses, HPV13 and HPV32 are frequently left out of standard HPV genotyping kits. To find HPV13 and HPV32, PCR analysis was performed using certain primers, and occasionally, DNA sequencing was employed. As an alternative, non-invasive methods such as cytobrushes can be used to obtain oral cells for examination, simplifying testing on youngsters and in outdoor environments.

How Is Heck's Disease Linked to Immunosuppressive Conditions and Specific Diseases?

It has been documented that focal epithelial hyperplasia coexists with several illnesses, especially in immunocompromised individuals. FEH is more common in those with intestinal lymphangiectasia or HIV who have lower amounts of naïve CD4+ T-cells. For instance, when the patient's HIV treatment got better, the FEH lesions got worse in one HIV case.

Sixty-two percent of HIV-positive patients in more extensive research had FEH, with 26 percent having HPV13 and 31 percent having HPV32 infections. Patients with lung transplants, chronic graft-versus-host disease, leukocyte adhesion deficit, lymphopenia (low white blood cell count), hypogammaglobulinemia (low levels of antibodies in the blood), and rheumatoid arthritis (a chronic inflammatory joint disease) have also been reported to have focal epithelial hyperplasia.

What Are the Challenges and Treatments for Heck's Disease, and Vaccine Impacts?

Since HPV's life cycle depends on host cell differentiation, preclinical research on focal epithelial hyperplasia is difficult because native HPV can only be created in living things. Although artificial viral particles are used in in vitro research to get around this need, preclinical models of HPV13 and HPV32 are not yet available. Nonetheless, FEH spontaneously evolved in a transgenic mouse model containing HPV16 E6/E7 oncogenes, making it an invaluable resource for researching the illness.

Clinically, FEH nodules frequently go away independently without posing any long-term problems. Lesions can last for several weeks to more than 30 years, and in many instances, they are asymptomatic and do not need to be treated. HPV vaccination is advised to avoid high-risk coinfections. Cervarix (which targets HPV16 and 18), Gardasil (which targets HPV6, 11, 16, and 18), and Gardasil 9 (which targets additional genotypes such HPV31, 33, 45, 52, and 59) are the three vaccines that are now available.

It has been demonstrated that Gardasil elicits cellular and antibody responses. It is crucial to vaccinate children and young people against FEH because of this. In many areas, HPV vaccination campaigns have considerably decreased the prevalence of oral HPV; nevertheless, HPV13 and HPV32 are not currently covered by the vaccines. It is currently uncertain how these vaccinations will affect these particular low-risk genotypes.

Treatment options for big or troublesome focal epithelial hyperplasia lesions include cauterization, liquid nitrogen local cryotherapy, Imiquimod five percent cream, laser treatments, and trichloroacetic acid. Imiquimod has been applied again to treat recurrences effectively.

Conclusion

HPV13 and HPV32 are the primary causes of focal epithelial hyperplasia, whereas high-risk HPV16 and HPV18 can also play a role in some cases. Current HPV vaccinations cover HPV16 and HPV18, while HPV13 and HPV32 do not. As a result, their effect on Heck’s disease is uncertain. However, there may be some cross-protection. Histopathology and clinical examinations are typically used to diagnose FEH, while HPV testing is recommended to prevent misdiagnosis. According to reports, there is a rise in FEH cases in Europe, highlighting the need for additional study.