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BCC variantAdnexalICD-10 C44

Fibroepithelioma of Pinkus

Pinkus tumour; FEP; premalignant fibroepithelial tumour of Pinkus; epithelioma adenoides cysticum (older term, distinct entity)

Fibroepithelioma of Pinkus is an uncommon distinctive variant of basal cell carcinoma with prominent fibroepithelial / adnexal differentiation, presenting as a solitary, smooth, dome-shaped, pink to skin-coloured papule or plaque most commonly on the lumbosacral back. Originally described by Hermann Pinkus in 1953 as a premalignant fibroepithelial tumour, it is now classified as a BCC variant in WHO 2018. Clinically it is frequently misdiagnosed as acrochordon, seborrhoeic keratosis, fibroma or naevus — the diagnosis is almost always made on histology after excision for diagnostic uncertainty or cosmetic concern. Indolent behaviour; complete surgical excision is curative.

CurrentLast reviewed 15 May 2026

Clinical features

  • Solitary smooth, dome-shaped or pedunculated pink to skin-coloured papule or plaque, 5–20 mm.
  • Common sites — lumbosacral back (~ 60%), trunk, occasionally extremities or genitalia.
  • Median age 50–70; slight female predominance.
  • Slow growth over months to years; usually asymptomatic.
  • Lacks the characteristic pearly margin, telangiectasia and ulceration of typical BCC.
  • Often clinically diagnosed as a skin tag, SK or banal pedunculated lesion until excision.

Histology

  • Anastomosing thin strands and trabeculae of basaloid cells extending downwards from the epidermis, embedded in a fibromyxoid stroma — characteristic "fenestrated" / "interconnecting trabecular" pattern.
  • Peripheral palisading and clefting between tumour cells and stroma — features of BCC.
  • Adnexal / follicular differentiation may be present.
  • Distinct from acrochordon (no basaloid trabeculae), seborrhoeic keratosis (squamoid keratinocytes), trichoblastoma (more lobular structure).
  • Stromal myxoid change and frequent admixture with conventional BCC nests in some cases.

Management

  • Complete surgical excision with conventional BCC margins (3–4 mm for low-risk sites).
  • Mohs micrographic surgery rarely needed — most lesions are well-circumscribed at low-risk sites.
  • Histology guides margin assessment; behaves indolently.
  • Reassurance after complete excision; recurrence uncommon.
  • Multiple lesions — consider Gorlin syndrome (rare); routine examination of the patient for other BCCs.

References

  1. Pinkus H. Premalignant fibroepithelial tumors of the skin. AMA Arch Derm Syphilol; 1953 (original).
  2. Sellheyer K, Krahl D. Fibroepithelioma of Pinkus — molecular study suggesting BCC variant rather than trichoblastic neoplasm. Br J Dermatol; 2012.
  3. WHO Classification of Tumours Editorial Board. Skin Tumours, WHO Classification of Tumours, 5th ed., vol. 12. Lyon: IARC; 2025.

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