Skin nonmelanocytic tumor

Contributed by Arvind Ranchhod, M.B.Ch.B.


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Contributed by Alexander Nirenberg, M.B.B.S.

Contributed by Alexander Nirenberg, M.B.B.S.

• Left neck, shave biopsy:
  • Fibroepithelial polyp / acrochordon (see comment)
  • Comment: Shave biopsy of skin tag from the left side of the neck (62 year old woman).
  • Macroscopic description: A skin covered polyp, X x Y mm, with a tan smooth surface. Cut surface is uniform and pale.
  • Microscopic description: A polyp covered by mildly acanthotic epidermis with mild hyperkeratosis. There is a mildly cellular fibrovascular core with scattered dilated small thin walled vessels and a sparse lymphocytic infiltrate. Dysplasia or malignancy is not seen.

• Polypoid / papillary variants of:
  • Seborrheic keratosis (Arch Dermatol 1996;132:1459):
    • Generally lacks the fibrovascular core of a fibroepithelial polyp
    • Dermatosis papulosa nigra:
      • Considered to be a seborrheic keratosis; however, it has a well developed fibrous stroma
      • It is a clinically distinct entity (Clin Dermatol 2017;35:491)
  • Verruca vulgaris / squamous cell papilloma (Australas J Dermatol 2019;60:70):
    • Epidermal papillomatosis with coarse hypergranulosis
    • May have koilocytosis
    • Hyperkeratosis with columns of parakeratosis
  • Melanocytic nevus (Arch Dermatol 1996;132:1459):
    • Melanocytic proliferation within the polyp
    • Commonly intradermal or compound
  • Neurofibroma (Australas J Dermatol 2019;60:70):
    • Cellular stromal proliferation of spindle cells with wavy nuclei
    • Mast cells within the lesion
  • Hemangioma and pyogenic granuloma (Arch Dermatol 1996;132:1459):
    • Large number of vessels in the stroma
  • Fibroepithelial tumor of Pinkus:
    • Thin anastomosing strands of basaloid or squamous keratinocytes projecting downward from the epidermis in a fenestrated pattern
    • Abundant fibrous stroma (Am J Dermatopathol 2005;27:149)
  • Polypoid trichodiscomas and fibrofolliculomas in Birt-Hogg-Dubé syndrome:
    • Infundibular structures in the stroma (Am J Dermatopathol 1999;21:369)
  • Accessory tragus:
    • Most commonly preauricular
    • Vellus hairs, eccrine glands, adipose tissue and cartilage in the stroma (J Am Acad Dermatol 2007;56:AB54)
  • Supernumerary digit:
    • Congenital
    • Increased peripheral nerves in the stroma (Arch Dermatol 1973;108:223)
  • Acquired digital fibrokeratoma:
    • Acral skin
    • Marked epidermal acanthosis and hyperkeratosis
    • Thickened stromal collagen parallel to the long axis of the lesion (J Am Acad Dermatol 1985;12:816)

A 62 year old woman presents with multiple lesions on the neck (shown above) with pathological diagnosis of fibroepithelial polyps, NOS. Which clinical association should you consider?

1. Anorexia
2. Birt-Hogg-Dubé syndrome
3. Diabetes mellitus
4. Dysplastic nevus syndrome
5. Neurofibromatosis

C. Diabetes mellitus. Skin tags may be associated with diabetes mellitus / metabolic syndrome as well as obesity. The other listed conditions have not been shown to have increased incidence of fibroepithelial polyps but may have other cutaneous polypoid lesions. Birt-Hogg-Dubé syndrome was initially reported as having increased incidence of skin tags, however, the lesions are polypoid trichodiscomas and fibrofolliculomas.

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Reference: Cutaneous fibroepithelial polyps

A clinician excises a skin tag from the groin of a 73 year old woman (microscopic image shown above). The best diagnosis is

1. Cutaneous myxoma
2. Neurofibroma
3. Pseudosarcomatous fibroepithelial polyp
4. Pyogenic granuloma
5. Traumatized fibroepithelial polyp

E. Traumatized fibroepithelial polyp. This is a fibroepithelial polyp with features of trauma, including an area of epidermal necrosis, stromal edema and stromal inflammatory cells. The stroma is loose and has low cellularity of mesenchymal cells, unlike a neurofibroma. The stroma is edematous rather than myxoid. It lacks the pleomorphic stellate and multinucleated stromal cells of a pseudosarcomatous fibroepithelial polyp. The lesion has dilated vessels, however, it lacks the lobular proliferation of capillaries that characterizes a pyogenic granuloma.

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Reference: Cutaneous fibroepithelial polyps