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A 1-year-old boy presented with a nodular lesion on the second toe of the left foot and was admitted to our hospital. The lesion had first emerged when the child was six months old and had gradually increased in size. The child had been born of non-consanguineous parents, had developed normally, and had no history of trauma. Skin examination showed a solitary, flesh-colored, firm nodule measuring 4 × 3 × 2 cm on the extensor aspect of the distal and middle phalanx of the left second toe (Fig. 1). There was no functional impairment. An x-ray of the left foot showed normal structure and density of the second phalanx without bone involvement. Excision biopsy was performed, and the lesion was completely resected. A full-thickness skin graft was performed using skin taken from the groin. Macropathological observation of the resected tumor revealed tube-like structures in the longitudinal section. Micropathological examination showed fibroblast proliferation throughout the dermis and eosinophilic intracytoplasmic inclusion bodies in fibroblasts (Fig. 2a). Immunohistochemistry (IHC) showed smooth muscle actin (SMA) (+), muscle-specific actin (MSA) (+), and anaplastic lymphoma kinase-1 (ALK-1) (−); Masson staining revealed inclusion body-like material (Fig. 2b). A diagnosis of infantile digital fibromatosis (IDF) was confirmed. The boy recovered satisfactorily and was discharged five days after the operation. No recurrence was seen during the two years and eight months of follow-up.

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Figure 1.  A 4 × 3 × 2-cm, pink, round, smooth, non-tender, hard nodular lesion is firmly attached to the skin and underlying tissues of the second toe of the left foot

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Figure 2.  (a) Histology shows eosinophilic cytoplasmic inclusions in large numbers in the tissue. (Hematoxylin and eosin stain; original magnification ×400.) (b) The inclusion body-like material stained red. (Masson stain; ×400)

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Infantile digital fibromatosis, first described by Reye in 1965,1 usually appears in the first year after birth and tends to recur after resection. A diagnosis of IDF mainly depends on pathology; eosinophilic cytoplasmic inclusion bodies are the typical manifestation.2 Although consensus has been reached that IDF is composed mainly of myofibroblasts, the exact origin of the inclusion bodies remained elusive for some time. This issue was resolved by Mukai et al.,3 who used an innovative pretreatment procedure combining potassium hydroxide (KOH), ethanol, and trypsin in IHC to reveal actin filaments in the inclusion bodies. Detailed clinical information is helpful in the differential diagnosis. Pachydermodactyly commonly occurs in young adult males.4 Terminal osseous dysplasia and pigmentary defects appear only in juvenile females4 and are always accompanied by facial and eye abnormalities (such as colobomas or hypertelorism). Keloid develops after injury. Palmar and plantar fibromatosis commonly occur at aponeuroses; genetic predisposition towards these symptoms is well documented5. Calcium deposits can sometimes be detected in juvenile aponeurotic fibromas by x-ray.

The treatment for IDF remains controversial; the options include observation, drug injection and surgical correction. Our choice of surgical treatment was based on the cosmetic requirements of the parents, the potential functional impairment and the need for accurate diagnosis. According to Tan Baser et al.,6 who compared outcomes after observation and surgery, respectively, no spontaneous regression was observed in the “watch and wait” case, and no recurrence was observed in the resection case after two years of follow-up; the authors concluded that recurrence was the result of incomplete excision. Campbell and Petrick7 recently reported the use of Mohs micrographic surgery (MMS) to treat a large IDF lesion (measuring approximately 4 cm) and described satisfying short- and long-term effects. We think complete resection is important and accomplishable because an IDF lesion can be differentiated from normal tissue during surgery. As the most precise method of tumor removal, MMS is helpful to confirm the tumor-free margin and to minimize the chance of regrowth and lessen the potential for scarring or disfigurement. By contrast, many clinicians prefer to use non-surgical treatments and achieve good effects. In 2005, Oh et al.8 reported their experience of treating a 7-year-old girl with a 1.4 × 0.8-cm IDF lesion by intralesional injection of 5-fluorouracil; this treatment was described as effective, and no recurrence occurred during the two-year follow-up. Another recent prospective and comparative study by Holmes et al.9 demonstrated that intralesional corticosteroid (triamcinolone) injection was safe and well tolerated as a treatment for all symptomatic digital fibromatoses in infancy and suggested that it should replace surgery as the first-line treatment for IDF. However, this requires further testing on a larger trial basis.

References

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  2. References
  • 1
    Reye RDK. Recurring digital fibroma of childhood. Arch Pathol1965; 80: 228231.
  • 2
    Grazia M, Oranje AP, den Hollander JC, et al. Fibromatoses, hyalinoses, and stiff skin syndrome. In: Harper JH, Oranje AP, Prose N, eds. Textbook of Pediatric Dermatology, Vol. 1, 2nd edn. London: Blackwell Publishing, 2006: 935956.
  • 3
    Mukai M, Torikata C, Iri H, et al. Immunohistochemical identification of aggregated actin filaments in formalin-fixed, paraffin-embedded sections. I. A study of infantile digital fibromatosis by a new pretreatment. Am J Surg Pathol1992; 16: 110115.
  • 4
    Niamba P, Léauté-Labrèze C, Boralevi F, et al. Further documentation of spontaneous regression of infantile digital fibromatosis. Pediatr Dermatol2007; 24: 280284.
  • 5
    Fetsch JF, Laskin WB, Miettinen M, et al. Palmar-plantar fibromatosis in children and preadolescents :a clinicopathologic study of 56 cases with newly recognized demographics and extended follow-up information. Am J Surg Pathol2005; 29: 10951105.
  • 6
    Tan Baser N, Tuncali D, Balci Akbuga U, et al. Infantile digital fibromatosis: late results of two different treatment approaches. Eur J Plast Surg2006; 29: 3840.
  • 7
    Campbell LB, Petrick MG. Mohs micrographic surgery for a problematic infantile digital fibroma. Dermatol Surg2007; 33: 385387.
  • 8
    Oh CK, Son HS, Kwon YW, et al. Intralesional fluorouracil injection in infantile digital fibromatosis. Arch Dermatol2005; 141: 549550.
  • 9
    Holmes WJ, Mishra A, McArthur P. Intralesional steroid?for the management of symptomatic infantile digital fibromatosis. J Plast Reconstr Aesthet Surg2011; 64: 632637.