Acrochordons (fibroepithelial polyps, skin tags, papillomas) are common benign neoplasms of the skin, often associated with obesity. These small polyps are frequently a nuisance for patients, typically developing around the neck, axilla, and groin areas. They may bother patients because of associated symptoms such as itching, pain, and rubbing against clothes or simply because of their appearance. There may be a familial predisposition for developing these lesions, as well as the established association with obesity and insulin resistance.
Skin tags are strongly associated with obesity and insulin resistance. Along with many other types of common benign skin lesions found on a skin exam of most adult patients (benign melanocytic nevi, seborrheic keratoses, cherry angiomas), they develop increasingly with age, and despite their benign nature, they can be of great concern and impact a patient's quality of life. Other common benign lesions can mimic acrochordons, including benign melanocytic nevi and neurofibromas.
Without histological confirmation, acrochordons cannot reliably be distinguished from benign melanocytic nevi and neurofibromas. However, since all of these likely possibilities in the differential diagnosis are benign, pathologic confirmation of such a diagnosis is not typically necessary since it will not impact management. Other common benign lesions that can overlap clinically with acrochordons are seborrheic keratoses. For instance, some seborrheic keratosis, specifically the variant termed dermatosis papulosis nigra (DPN), may overlap clinically with acrochordons on the face. Dermatosis papulosa nigra typically present in a pattern of small, typically pigmented, pedunculated or simply raised papules on the face and adjacent structures. These are most common in patients of African-American descent.
Of note, one inherited syndrome is frequently discussed in the context of acrochordons. This syndrome, Birt-Hogg-Dube syndrome (BHD syndrome), is a rare autosomal dominant genodermatosis characterized by multiple fibrofolliculomas and trichodiscomas that may be indistinguishable from acrochordons. Birt-Hogg-Dube syndrome is caused by a mutation in the FLCN gene that produces folliculin, a tumor suppressor protein. Reported associations with Birt-Hogg-Dube syndrome include spontaneous pneumothorax and renal cell carcinoma (especially chromophobe and hybrid oncocytic carcinomas).
In addition, one variant of basal cell carcinoma may present with clinical overlap with acrochordons. The fibroepithelioma of Pinkus is a subtype of basal cell carcinoma that is classically reported as a pink acrochordon-like lesion (pedunculated papule) appearing on the lower back. This was first described by Hermann Pinkus in 1953 as a premalignant fibroepithelial tumor.
Acrochordons have a high prevalence, reportedly 46% of the general population, increasing in frequency with patient age. Given that so many patients may have acrochordons, patients should be reassured that these are common benign lesions that should not be concerning.
Acrochordons typically do not need to be examined with histopathology. That said, when sampled, pathology reveals a papillary dermis composed of loosely arranged collagen fibers and dilated capillaries and lymphatic vessels, without appendageal structures (hair follicles, sweat glands). It is still possible, however, unlikely, to have a concerning lesion present clinically as an acrochordon or as a component of an acrochordon. This includes such neoplasms as malignant melanoma, squamous cell carcinoma, or basal cell carcinoma (notably, the basal cell carcinoma subtype fibroepithelioma of Pinkus, which may present as an acrochordon-like pink papule in the lower back).
These cases are exceedingly rare, however, and it would not be considered cost-effective to regularly evaluate acrochordon-like lesions with pathology unless there is a particular indication. These indications include clinical suspicion for one of these more concerning lesions (dysplastic or atypical nevi, malignant melanoma, basal cell carcinoma, squamous cell carcinoma), presentation of the acrochordon-like growth as a new or changing lesion, or concern for Birt-Hogg-Dube or similar syndrome.
Acrochordons are pedunculated skin growths most commonly located on the neck, axilla, and inguinal folds (typically in intertriginous areas), though they can appear in almost any part of the skin. They present as pedunculated polyps that may range from skin-colored to hyperpigmented. Occasionally, these lesions may be hyperkeratotic or filiform (a warty appearance), and may, in fact, have a concurrent wart (verruca vulgaris). Around the neck and axilla, acrochordons may present concurrently with acanthosis nigricans, the velvety brown plaques that may also occur in these same areas. The parallel presentation of both acrochordons and acanthosis nigricans is not surprising as both are commonly associated with obesity and insulin resistance and diabetes. Along these lines, acanthosis nigricans may have a component of papillomatous changes apparent on histopathology.
Given the general lack of clinical concern when presented with these lesions on the exam, no laboratory, radiographic, or other tests are typically necessary to investigate patients with acrochordons. However, in the case that a clinician deems it necessary when removing multiple acrochordons to refer these specimens for pathologic evaluation, it is strongly recommended that each lesion is separated and placed in individually labeled containers. In the unlikely event that a lesion did end up being diagnosed as a concerning neoplasm (for instance, malignant melanoma), if all the lesions were placed in the same formalin specimen container, it would not be clear from which location the lesion of concern occurred. This would present an extremely difficult situation that common sense can avoid.
Patients should be reassured that acrochordons are benign. If irritated or cosmetically undesired, they may be treated with any destructive modality, but they are most commonly treated by snip excision (with scissors) or liquid nitrogen cryotherapy. Other options may include shave excision, electrocautery, and ligation (tying a string or suture around the lesion). Multiple lesions may be treated at one visit, although some patients may prefer to have one individual lesion treated first as a test spot.
If a patient is suspected to have concurrent acanthosis nigricans, patients should be advised of the potential risk for diabetes. Such patients should be referred back to primary care and engage in discussions around the modification of diet and exercise. Even when acrochordons are present on the exam in isolation, since these patients often do have comorbidities including obesity, diabetes, or prediabetes, it is reasonable for any physician to encourage healthy eating habits, exercise, and other behavior modification to encourage benefits beyond the skin exam.