Digital fibromas may be found in children or adults, and consist of solitary or multiple papules or nodules on the fingers or toes. Histologically, they consist of benign-appearing spindle cells devoid of cytologic atypia [1]. Infantile digital fibromatosis is a variant in young children, and is a rare benign fibroproliferative tumor of early childhood that typically spontaneously involutes in 2 to 3 years [2]. There is also a cellular variant that has dense CD 34+ spindle cells and may mimic dermatofibrosarcoma protuberans (DFSP) histologically. It important to correctly diagnose this variant of digital fibroma, considering the implications of an incorrect diagnosis of DFSP [3]. While typically a relatively small tumor, an acquired tumor has been reported grow quite large, with measurements of 2.5 × 1.6 × 1.4 cm, appropriately named in that report as “giant acquired digital fibroma” [4]. The cause of acquired digital fibromas is unknown; however, similar to plantar fibromas, they may be secondary to trauma [5]. In addition, there has been report of acquired digital fibrokeratoma caused by cyclosporine [6]. It is important to keep a wide differential diagnosis when a patient presents with a lesion on the digits.

These are prototypical cases of digital fibroma, however it is important to keep in mind that benign and malignant tumors can occur in the toes, including aggressive digital papillary adenocarcinoma mimicking acquired digital fibrokeratoma, and metatastic tumors from the viscera. Consider biopsying any new or recurrent mass, and any digital lesions not responding to treatment [7,8]. Histology differs based on the type of digital fibroma. Koenen tumors, which are periungual fibromas found in tuberous sclerosis, often originate from the proximal nail fold and show capillaries in the distal part surrounded by thin collagen bundles while the proximal part consists of dense, closely packed fibers [9,10]. Histology of recurrent digital fibroma of childhood shows round, eosinophilic cytoplasmic inclusion bodies, which are myofibroblastic in nature [11]. Interestingly, myofibrolastic features identical to those found in recurring digital fibroma of childhood were found in four patients involved in the toxic oil epidemic syndrome (TOES) in Spain in 1981, which caused generalized sclerodermoid skin changes [12]. As mentioned previously, treatment for infantile digital fibromatosis is typically observation, with spontaneous involution in 2-3 years as the rule. Identification of this entity is important to prevent an unnecessary surgical procedure [2]. Once other more dangerous conditions such as those previously mentioned have been excluded in acquired cases, shave excision under local anesthesia is appropriate management for digital fibromas [13].