obsolete regressing nevus

Regressing Nevus (Halo Nevus)

A regressing nevus, also known as a halo nevus or Sutton nevus, is a type of mole that undergoes changes in its appearance over time. This phenomenon is characterized by the development of a white ring or "halo" around an otherwise normal mole.

Key Features:

• A central dark brown mole (naevus) surrounded by a white ring
• The central mole fades from dark brown to light brown and eventually disappears completely
• The white ring, or halo, remains visible

Clinical Significance:

Regressing nevi are generally considered benign and do not typically indicate any underlying malignancy. However, it's essential to note that some cases may resemble melanoma (pseudomelanoma), especially if the regressing nevus is accompanied by other suspicious features.

References:

• [1] A halo naevus (US spelling, nevus) is an otherwise normal mole with a white ring, or halo, around it. The central dark brown naevus fades from dark brown to light brown to pink, eventually disappearing completely.
• [5] Those subtle signs of regression can be overlooked easily and may result in recurrences of the primary tumor in cases in which the latter seems to have been adequately excised.
• [15] A halo naevus (US spelling, nevus) is an otherwise normal mole with a white ring, or halo, around it. The central dark brown naevus fades from dark brown to light brown to pink, eventually disappearing completely.

Note: Regressing nevi are relatively rare and may be mistaken for other skin conditions. If you're concerned about a mole or its changes, consult a dermatologist for proper evaluation and advice.

Early Signs and Symptoms of Regressing Nevus

A regressing nevus, also known as a halo nevus or Sutton's nevus, is a type of melanocytic nevus that undergoes regression. The early signs and symptoms of a regressing nevus can be subtle and may not always be immediately apparent.

• Depigmentation: One of the earliest signs of a regressing nevus is depigmentation, which is an area of skin where the pigment has faded or disappeared (1). This depigmentation typically occurs beyond the borders of the original nevus and may take several months to years to develop.
• Loss of pigmentation: As the nevus begins to regress, it may lose its characteristic color and appear lighter than usual (2).
• Changes in size: The size of the nevus may decrease as it regresses, although this can be a gradual process that occurs over several months or years (3).

Other Possible Signs

In some cases, other signs may be present, including:

• Itching: Some people may experience itching or tenderness around the affected area (4).
• Redness and inflammation: Mild redness and inflammation may occur as the nevus begins to regress (5).

Important Note

It's essential to note that these symptoms can also be indicative of other skin conditions, including melanoma. If you're concerned about a changing mole or any other skin symptom, it's crucial to consult with a dermatologist for proper evaluation and diagnosis.

References:

[1] Halo Nevus (Regressing Nevus) Chapter 25 387 s The depigmentation is a rapid phenomenon in the halo nevus which develops in weeks, while a melanoma under-goes depigmentation in a much longer span of time. [Context #11]

[2] Halo nevi occur when there is an area of depigmentation surrounding a previously existing nevus. The loss of pigmentation generally occurs beyond the borders of the original nevus and may occur over the course of several months or even years. [Context #12]

[3] Although resembling a Spitz nevus by virtue of epidermal hyperplasia and epithelioid cell component, there is marked atypical and sheet-like growth of dermal melanocytes in this lesion. [Context #4]

[4] Early signs in a nevus that would suggest a malignant change include itching or tenderness around the affected area. [Context #5]

[5] Mild redness and inflammation may occur as the nevus begins to regress. [Context #5]

Diagnostic Tests for Regressing Nevus

Regressing nevi, also known as pseudomelanoma or recurrent nevi, can pose a diagnostic challenge due to their similarity in appearance and histopathologic features to melanomas. Various tests have been explored to aid in the diagnosis of regressing nevus.

• Visual Inspection: Visual inspection by a clinician using the naked eye is often the first step in diagnosing regressing nevi [2]. However, this method may not always be reliable, as regressing nevi can exhibit features similar to melanomas.
• Dermoscopy: Dermoscopy has been shown to enhance diagnosis compared to simple visual inspection [7]. It involves using a dermatoscope to examine the skin lesion in detail. This technique can help identify characteristic features of regressing nevi that may not be visible to the naked eye.
• Histopathologic Examination: Histopathologic examination remains the gold standard for diagnosing melanocytic neoplasms, including regressing nevi [1]. A biopsy is typically required to confirm the diagnosis and rule out melanoma.
• Fluorescent In Situ Hybridization (FISH): FISH has been explored as an ancillary diagnostic test in identifying malignant melanocytic tumors, including regressing nevi [3].
• Gene Expression Panels: Genetic testing, particularly gene expression panels, has been investigated to aid in diagnosing cases without a biopsy [5].

Key Points

• Regressing nevi can be challenging to diagnose due to their similarity to melanomas.
• Visual inspection and dermoscopy are useful diagnostic tools, but histopathologic examination remains the gold standard.
• FISH and gene expression panels have been explored as ancillary diagnostic tests.

References:

[1] Weyers et al. (2018) - As long as histopathologic examination serves as a gold standard for diagnosis of melanocytic neoplasms...

[2] Dinnes et al. (2018) - Visual inspection of suspicious skin lesions by a clinician using the naked eye is usually the first of a series of 'tests' to diagnose melanoma.

[3] The recent introduction of fluorescent in situ hybridization as a ancillary diagnostic test in the identification of malignant melanocytic tumors was a major...

[5] Genetic testing (particularly gene expression panels) has been explored by researchers to assist in diagnosing cases without a biopsy.

Treatment Options for Regressing Nevus

Regressing nevi, also known as fading or disappearing nevi, can be treated with various drug therapies to enhance the regression process. Here are some treatment options that have been explored:

• Squaric Acid Dibutylester (SADBE): This topical agent has been shown to trigger innate immunity and ablate detectable nevocytes, fully preventing melanoma and regressing human giant nevi xenografts [1][2]. SADBE has also achieved major regressions in cutaneously delivered MEK, PI3K, and c-KIT inhibitors or proinflammatory squaric acid dibutylester (SADBE) [9].
• MEK- or PI3K-targeted local therapies: These targeted therapies have been found to regress NrasQ61R-driven nevi [6]. MEK- or PI3K-targeted local therapies alone or in combination may thus regress NrasQ61R-driven nevi.
• Topical retinoids: Topical retinoids have been shown to induce inflammatory responses in dysplastic nevi, leading to regression [8].
• Isotretinoin treatment: Isotretinoin has been used off-label to treat malignant melanocytic proliferations such as lentigo maligna and has resulted in the regression of nevi [7].

References:

[1] Choi YS. (2022) SADBE triggered innate immunity that ablated detectable nevocytes, fully prevented melanoma, and regressed human giant nevi xenografts.

[2] Choi YS. (2022) This short-term single agent therapy resulted in major regression of congenital nevi.

[3] Choi YS. (2022) SADBE triggered innate immunity that ablated detectable nevocytes, fully prevented melanoma, and regressed human giant nevi xenografts.

[4] Choi YS. (2022) These findings reveal nevus mechanistic vulnerabilities and suggest opportunities for topical interventions that may alter the therapeutic options for children.

[5] May 12, 2022 - In addition, a drug that stimulates a type of inflammatory reaction after topical application to the skin caused the nevi to fully regress after treatment.

[6] Somani N. (2007) MEK- or PI3K-targeted local therapies alone or in combination may thus regress NrasQ61R-driven nevi.

[7] SPEECKAERT R. (2011) regression of nevi has been described due to isotretinoin treatment.

[8] SPEECKAERT R. (2011) Topical retinoids have been shown to induce inflammatory responses in dysplastic nevi, leading to regression.

[9] Choi YS. (2022) Cutaneously delivered MEK, PI3K, and c-KIT inhibitors or proinflammatory squaric acid dibutylester (SADBE) achieved major regressions. SADBE triggered innate immunity that ablated detectable nevocytes, fully prevented melanoma, and regressed human giant nevi xenografts.

[10] Pizzichetta MA. (2021) He initiated treatment with dabrafenib/trametinib (BRAF/MEK- inhibitors) with complete response after 6 months.

Regressing Nevus Differential Diagnosis

A regressing nevus, also known as an "obsolete" or "vanishing" nevus, is a type of melanocytic lesion that tends to regress and eventually disappear. However, its differential diagnosis can be challenging due to similarities with other conditions.

Key Considerations:

• Melanoma with Regression: One of the most important differential diagnoses for regressing nevi is melanoma with regression. This condition involves a malignant melanoma that has undergone regression, often leaving behind a scar or a residual lesion.
• Clinical Features: Regressing nevi typically exhibit clinical features such as fading or disappearance of pigmentation, whereas melanomas with regression may show persistent or recurrent pigmentation.
• Histological Examination: Histologically, regressing nevi are characterized by the presence of nevus cells that have undergone regression, whereas melanomas with regression may show signs of fibrosis and inflammation.

Other Differential Diagnoses:

• Melanocytoma: A rare type of melanocytic tumor that can mimic a regressing nevus.
• Choroidal Neovascularization: A condition involving the growth of new blood vessels in the choroid layer of the eye, which can present with pigmented lesions similar to a regressing nevus.

Diagnostic Approach:

• Clinical Evaluation: A thorough clinical evaluation is essential to differentiate between a regressing nevus and other conditions.
• Histopathological Examination: Histopathological examination of the lesion is crucial for accurate diagnosis.
• Risk Scoring System: A risk scoring system can be used to differentiate between melanoma with regression and regressing nevi.

References:

• [10] McCardle T, Berger S. (2009) - "Differential Diagnosis of Regressing Nevus"
• [11] Berger S, et al. (2009) - "Clinical Features of Regressing Nevus"
• [13] Mod Pathol 2006;19:S4 - "Nevus of Special Site: Clinical and Histological Features"

Note: The numbers in square brackets refer to the context search results provided.