Infantile Digital Fibromatosis: A Rare Case Report.

Sir,

Infantile digital fibromatosis (IDF) is a smooth, firm, erythematous or skin-colored nodule on the dorsal or lateral surfaces of the distal phalanges of the fingers and toes. Usually, thumb and great toe are spared. Extra digital involvement is rare but reported in literature. More than 80% of tumors are present in infancy. Spontaneous resolution of lesions over 1–10 years (average 2–3 years) is seen. Recurrence is common after excision.

A 9-month-old Indian girl presented to skin outpatient department with multiple reddish to skin-colored, confluent, small, painless, indurated, papulonodular lesions on the dorsum of the right foot, which progressively increased in size starting at 1 month after birth.

The girl was born out of nonconsanguineous marriage. Previous medical history was unremarkable, and there was no history of trauma or inflammation. No allergic history was reported. The other foot and both hands were unremarkable. No other skin lesions were present over the body. None of the family members had similar lesions.

There were swelling and deformity of the second, third, and fourth toe of the right foot. Second toe was enlarged in size and displaced over great toe. Middle toe was the most enlarged and had ulceration over dorsal surface. The skin overlying the swelling over toes was firm and reddish blue [Figure 1]. The ulceration on dorsum of the middle toe was due to friction while crawling by the baby. Sole of the foot also had swelling and nodular lesions on the base of the second, third, and fourth toe [Figure 2]. Great toe and little toe was spared.

Figure 1

Smooth, skin-colored to erythematous papulonodular swelling affecting the second, third, and fourth toe of the right side

Figure 2

Plantar aspect of foot showing papulonodular lesions

There was pain and slight functional impairment while crawling by the child. No signs of scratching were present. Further systemic clinical examination was normal.

Provisional diagnosis of IDF, localized neurofibromatosis, arteriovenous malformation, and proteus syndrome was kept.

X-ray of the local part revealed the cutaneous and subcutaneous location of the lesion and bony architecture was normal. Ultrasonographic examination of the foot revealed soft-tissue thickening in subcutaneous areas with lack of any venous pockets or arteriovenous malformation.

A 3-mm punch biopsy was performed under local anesthesia, and histopathology revealed a fibromatosis affecting the reticular and adventitial dermis. The biopsy showed tumor showing spindle cells extending from papillary dermis to the subcutis. Infiltrated spindle cells were uniform and formed interlacing fascicles throughout the dermis. Few osteoclast-like giant cells were visible in the superficial dermis. Some of the fascicles showed small, round, eosinophilic cytoplasmic inclusions indenting the nucleus [Figures 3 and 4]. The overlying epidermis was unremarkable. A final diagnosis of congenital IDF was suggested. As the current literature recommends avoiding surgical intervention, no invasive treatment was sought. A topical treatment with fusidic acid 1% cream twice daily along with oral cephalexin syrup of 125 mg/5 ml was given for 5 days. Subsequently, topical applications of fluticasone cream were given for 4 weeks. Three months later, the papular skin lesions reduced; however, deformity of toes and foot swelling remained unaltered [Figure 5].

Figure 3

High-power histological presentation of the characteristic perinuclear cytoplasmic cellular inclusions found in infantile digital fibromatosis (H and E)

Figure 4

Low-power view of histopathological section stained with H and E showing uniform infiltrated spindle cells were and formed interlacing fascicles throughout the dermis

Figure 5

Follow-up image after 3 months of treatment showing slight reduction in lesions

IDF is a rare tumor usually affecting one or more digits. Numerous synonyms describe IDF, including Reye's tumor, multiple hyaline fibromatosis, infantile dermal fibromatosis, inclusion body fibromatosis, subdermal fibromatosis tumor of infancy, and juvenile dermatofibroma.[12]

IDF typically develops during the 1st year of life and the majority of cases are sporadic. Congenital onset is rare but it is also described.[3]

Clinically, IDF presents as smooth, round, indurated, confluent nodules up to 2 cm in diameter. The lesions can be single or multiple. The color of the skin can be pink to reddish. Initially, IDF manifests an indolent course. It can follow a rapid growth phase during several months following which the tumor size remains stable until spontaneous regression without scarring occurs.[45]

IDF is usually painless and nonpruritic.

It is localized usually on the lateral and dorsal aspects of the fingers and/or toes sparing the thumb and the great toe. Ulceration may occur. Functional impairments or deformities are rare. Although fingers are the most common site, IDF can be observed in babies without finger involvement.[6]

The differential diagnosis of IDF includes keloids, hypertrophic scar tissue, terminal osseous dysplasia and pigmentary defects, and juvenile aponeurotic fibroma.

As spontaneous involution of IDF is known, surgical intervention should generally be avoided unless surgery is warranted by functional impairment. Surgical treatment of IDF consist of excision, amputation, and skin graft, but recurrence is known in up to 75% of patients after simple excision.[7] Topical agents such as imiquimod (which inhibits human fibroblast collagen production by interferon α [INF-α] and INF-γ) has been tried with limited success. Topical and intralesional corticosteroids have been used owing to their antifibrotic properties.

Recognition and diagnosis are essential to avoid unnecessary surgical intervention and morbidity. Counseling of parents regarding benign nature of the condition is essential. Conservative approach until spontaneous involution is the best strategy at present.

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Conflicts of interest

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