Acquired digital fibrokeratoma (ADFK) is a rare, benign, CD34-negative, or focally CD34-positive, fibrous tumor that may be localized to the nail unit, where it is termed an acquired ungual fibrokeratoma (AUFK) [1, 2]. AUFK typically arises from the proximal nail matrix or nail bed [3]. AUFK consists of dense collagen fibers with increased levels of fibroblasts and capillaries compared to the dermis, suggesting that the tumor may result from erroneous collagen formation by fibroblasts [1, 4]. Factor XIIIa, an intracellularly produced coagulation factor that stimulates the proliferation of fibroblasts, is expressed in ADFK and may play a role in its pathogenesis by acting as a growth factor promoting tumor development [5, 6]. Some studies cited herein refer to ADFK instead of AUFK due to the rarity of the latter. The reference to each study distinguishes whether the inclusion criteria included ADFK vs. AUFK specifically.