Pedunculated Hemorrhagic Cystic Swelling: An Unusual Presentation of Polydactyly.

Sir,

A 3-week-old otherwise healthy baby girl was brought to the dermatology outpatient department with a hanging globular mass filled with hemorrhagic fluid from the left little finger of 3 days duration. She was the third child born out of a non-consanguineous marriage following uneventful pregnancy. The mother gave a history of asymptomatic skin-colored growth on the ulnar side of both the little fingers at birth. Three days back, she noticed a band formation at the proximal part of the digit leading to blackish discoloration on the distal part with gradual swelling. There was no history of tying anything at the base prior to the onset of swelling. Examination revealed a firm 3 mm long linear outgrowth on the ulnar side of the right little finger [Figure 1]. On the left side, the skin tag had a distal pedunculated, globular (approximately 1.5 cm in diameter), partially compressible swelling filled with hemorrhagic fluid [Figure 2]. Closer inspection revealed approximately 3 mm round, firmly adherent, thin nail plate, surmounting this globular mass. The swelling was excised by radiofrequency ablation, and the tissue sent for histopathologic examination, which showed an ulcerated lesion with a hyaline cartilage in the centre surrounded by fibrofatty tissue, confirming it to be an accessory digit [Figure 3].

Figure 1

Firm linear outgrowth approximately 3 mm in length simulating skin tag on the ulnar side of the right little finger

Figure 2

Excised distal pedunculated, globular, soft, partially compressible, hemorrhagic lesion (approximately 1.5 cm in diameter), separated by a sharp constriction on the ulnar aspect of the left little finger. Note the tiny nail plate surmounting the swelling

Figure 3

Ulcerated lesion with a hyaline cartilage in the centre surrounded by fibrofatty tissue (H and E, ×100)

Polydactyly is characterized by the presence of extra digits beyond the normal complement of 1 thumb and 4 fingers and is the most common congenital digital anomaly of the hand with a prevalence of 5–19 per 10000 live births.[1] Polydactyly can be isolated (autosomal dominant) or syndromic (autosomal recessive). It is classified on the basis of the anatomical location of the extra digit into preaxial ( first digit-thumb or great toe), postaxial (5th digit) and central (3 central digits), with preaxial being the most common.[2]

Postaxial polydactyly is common in African and African American population, usually inherited as an autosomal dominant trait with variable penetrance. It is often associated with syndromes such as Ellis–van Creveld or chondroectodermal dysplasia, mainly in the Caucasian population requiring further evaluation.[3] Clinically, its presentation varies from a well-recognized skin tag to a fully duplicated digit, and is classified into two types, namely, type A and B.[2] In type A, the extra digit is well formed and articulates with the 5th or an extra digit, and in type B, the extra digit frequently presents as a skin tag or a pedunculated soft tissue mass devoid of any bone, tendon, or nail.[45] On review of literature, we did not find description of any atypical or unusual clinical presentation of postaxial polydactyly. To the best of our knowledge, the rapidly increasing hemorrhagic swelling, as seen in our patient, is a hitherto undescribed presentation of polydactyly.

Type A requires formal reconstruction with transfer of important anatomical structures.[6] While type B can be treated with surgical excision or suture ligation of the pedicle.[6] Suture ligation disrupts the vascular supply leading to dry gangrene followed by auto-amputation of the rudimentary digit.[2] Wart-like scars, residual bumps, or neuromas may complicate ligation.[6] Wide-based extra digits are treated by surgical excision.[2]

Our patient fulfilled the diagnostic criteria for Type A postaxial polydactyly due to the presence of adherent nail plate over the swelling. The aforesaid presentation alarmed the child's parents to seek urgent medical attention. Knowledge of this otherwise common entity will help clinicians to decide the extent of workup essential to rule out any associated congenital defects.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.