Koenen's tumor

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Koenen's tumor
Other namesKoenen's periungual fibroma[1] and Periungual fibroma[2]
Koenen tumor in patient with tuberous sclerosis complex
SpecialtyDermatology

Koenen's tumor (KT), also commonly termed periungual angiofibroma,[1]: 668  is a subtype of the angiofibromas.[3] Angiofibromas are benign papule, nodule, and/or tumor lesions that are separated into various subtypes based primarily on the characteristic locations of their lesions. KTs are angiofibromas that develop in and under the toenails and/or fingernails.[4] KTs were once considered as the same as another subtype of the angiofibromas viz., acral angiofibromas. While the literature may still sometimes regard KTs as acral angiofibromas, acral angiofibromas are characteristically located in areas close to but not in the toenails and fingernails as well as in the soles of the feet and palms of the hands.[5][6] KTs are here regarded as distinct from acral angiofibromas.

KTs most commonly develop in individuals who have the rare

Birt-Hogg-Dube syndrome, has also been reported to have typical KT findings.[10]

KTs are strictly benign (i.e. do not

metastasize) but may be painful, disfiguring, and sometimes large and/or incapacitating lesions. They have often been treated by strictly local surgical resections. However, they do have a high rate of recurrence at the site of resection[11] and therefore have been treated with various other non-invasive local measures in efforts to avoid recurrences; these other methods have also been preferred to treat numerous tumors in individuals, for cosmetic reasons, and/or to relieve tumor-induce incapacitations.[11][12]

Presentation

In individuals with tuberous sclerosis, KTs commonly present with multiple firm red-colored to skin-colored nodules or tumors that emanate from the proximal nail fold or, less often, proximal skin beneath the nail. They often develop after puberty; increase in number over time; more frequently occur in the toenails than fingernails (the most common sites are on the big toe and thumb); are generally 5 to 10 mm in length but occasionally grow to far larger sizes;[4] and may be or become disfiguring, painful, and/or incapacitating.[13] Nearly 50% of post-puberty individuals with tuberous sclerosis have KTs.[11] (Tuberous sclerosis is also associated with a second type of angiofibroma, adenoma sebaceum, also termed facial angiofibroma, in ~75% of cases.[14]) Individuals presenting with KTs that do not have tuberous sclerosis commonly present with a single lesion in a nail bed.[15] KT may also present as a recurrence of a lesion at the site where it was surgically removed.[11] Rare cases of KTs have had a history of crushing trauma at the sites where the KTs later developed.[4]

Pathology

Microscopic

fibroblasts and ectatic blood vessels in a dense collagen fiber connective tissue background.[12]

Etiology

In cases associated with tuberous sclerosis, KTs appear to be a result of this disease's associated genetic abnormalities, i.e.

rapamycin, a drug which has been used as a topical application to successfully treat a few cases of Koenen's tumors.[12]

A small number of cases in individuals including those that do not have tuberous sclerosis may develop KTs as reactions to local traumas.[4]

Treatment

The treatment of KTs has varied depending on their size, numbers, locations, symptoms, damage to tissues, and disfiguring effects. Excision may be the treatment of choice for surgically accessible lesions.

laser vaporization; electrocauterization; shave excision of the tumor with phenolization (i.e. excision of the tumor’s protruding portion followed by treatment of the proximal perionych [i.e., skin around a nail] with phenol to eradicate the root of the tumor);[11] and in individuals with tuberous sclerosis, topical application of sirolimus, i.e. rapamycin, (1% solution).[12] Some of the latter methods have been used in order to preserve the nail matrix and nailplate and may be ideal for younger patients with few tumors since they may leave a normal appearing nail.[11]

See also

References

  1. ^
    ISBN 0-07-138076-0
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  2. ISBN 978-1-4160-2999-1
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  3. ISBN 978-3-030-58709-3
    .
  4. ^
    S2CID 232366948
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  5. PMID 27938817
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  6. S2CID 12366680
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  7. S2CID 28266318
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  8. S2CID 237555929
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  9. S2CID 5471149
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  10. PMID 27274535
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  11. ^
    S2CID 2048931
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  12. ^
    PMID 33614724
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  13. S2CID 41725531
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  14. PMID 33552794
    .
  15. ^
    S2CID 232311353
    .
  16. S2CID 221018594
    .
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