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 genetic disease, tuberous sclerosis[7] (a heritable neurocutaneous disorder[8]) and uncommonly in individuals that do not have this genetic disease.[9] One individual with another rare genetic disease that has similarities to tuberous sclerosis, the 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]
^ abFreedberg, et al. (2003). Fitzpatrick's Dermatology in General Medicine. (6th ed.). McGraw-Hill. ISBN0-07-138076-0.
^Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN978-1-4160-2999-1.
^Mocellin, Simone (2021). "57. Cutaneous angiofibroma". Soft Tissue Tumors: A Practical and Comprehensive Guide to Sarcomas and Benign Neoplasms. Switzerland: Springer Nature. pp. 189–192. ISBN978-3-030-58709-3.
^McNiff JM, Subtil A, Cowper SE, Lazova R, Glusac EJ (July 2005). "Cellular digital fibromas: distinctive CD34-positive lesions that may mimic dermatofibrosarcoma protuberans". Journal of Cutaneous Pathology. 32 (6): 413–8. doi:10.1111/j.0303-6987.2005.00358.x. PMID15953374. S2CID12366680.
^Zheng LQ, Huang Y, Han XC (May 2013). "Angiofibromas with multiple epidermoid cysts in tuberous sclerosis: new mutation or post-traumatic?". Journal of Cutaneous Pathology. 40 (5): 509–12. doi:10.1111/cup.12103. PMID23418925. S2CID28266318.
^Wang MX, Segaran N, Bhalla S, Pickhardt PJ, Lubner MG, Katabathina VS, Ganeshan D (September 2021). "Tuberous Sclerosis: Current Update". Radiographics. 41 (7): 1992–2010. doi:10.1148/rg.2021210103. PMID34534018. S2CID237555929.
^Longhurst WD, Khachemoune A (November 2015). "An unknown mass: the differential diagnosis of digit tumors". International Journal of Dermatology. 54 (11): 1214–25. doi:10.1111/ijd.12980. PMID26235189. S2CID5471149.