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digital fibrokeratoma

Sunday 10 January 2021

tuber ; Koenen tumor ; acquired digital fibrokeratoma



- tuber : pedunculated to dome shaped nodule on acral skin
- polypoid lesion
- hyperplastic epidermis
- variably acanthotic epidermis with hyperkeratosis / hyperkeratotic orthokeratosis
-  dermal anomalies : dense collagen fibers and variable amounts of mature fibroblasts, small blood vessels and elastic tissue
- thickened collagen in dermis is oriented predominantly in the vertical direction
- stellate stromal cells may be present
- Lesion merges with adjacent normal dermis
- neural structures are absent or inconspicious
- Lacks adnexal structures


- Koenen tumor in tuberous sclerosis - tuber

Differential diagnosis

- tuberous tumors

  • tuberous dermal melanocytic naevus

See also

-  cutaneous anomalies