Accessory auricles with ectopic digit a new association

Introduction

Ear develops from branchial arches and abnormalities of first and second bronchial arch may result in accessory auricles, congenital fistulae and other external ear malformations, transmitted as autosomal dominant trait.[1] Accessory auricle may occur alone or in combination with other abnormalities such as those of middle and inner ear and other organ systems.[2] Ear dysplasias were reported with developmental abnormalities of genitourinary tract.[3] CT scan was found to be more useful than MRI in the delineation of these ear anomalies.[4]

Supernumerary digit[5] is also an autosomal dominant developmental malformation, present from birth, often bilaterally. It arises from the surface of a normal finger, mainly on the ulnar border of the hand or near the base of the fifth digit, as a pedunculated nodule and is capped by a vestigial nail.

Congenital ectopic nail of the fifth finger has been described in literature.[6] But ectopic digit has not been reported so far.

Case Report

A 25-year-old man presented with a single, firm to hard, 2 cm, circular, well defined plaque covered with fine scales over the distal inter-phalangeal joint of left thumb and from its central depression protruded a firm digit, which was curved, 2.25 cm in length, with overlying normal skin and distal, which was curved, 2.25 cm in length, with overlying normal skin and distal nail formation [Figure - 1]. This digit was present since 1 year and patient got it removed surgically but it recurred 1 month back and slowly progressed to attain the present size. No history of injury was elicited and family history was also not contributory. Routine investigations were normal and X-ray examination of thumb revealed no bony growth.

Patient also had associated pre-auricular anomalies present in the form of two accessory auricles. Larger one was 2 x 0.5 cm, oval, skin coloured, firm nodule present just anterior to the tragus and another smaller one 0.3 cm, round, firm nodule present just above it [Figure - 1].

Discussion

Although ear malformations have been reported to be to associate with various organ abnormalities, association with ectopic digit has not been reported.

Clinical appearance, as confirmed from the photograph, clearly revealed that the left thumb lesion was an ectopic digit and had many differences from supernumerary digit such as appeared at the age of 24 years, recurred after surgical excision, was unilateral, was present on the distal interphalangeal joint of left thumb and protruded from central depression of an abnormal plaque present at its base rather than from the normal skin. Late onset of ectopic digit could be due to stimulation of ectopic germ cells by some unknown factors. Exact explanation for association of ectopic digit and accessory auricles cannot be given.