Clinical usefulness of ultrasonography in interdigital pilonidal sinus

Interdigital pilonidal sinus is an uncommon occupational disease produced by short sharp hairs that penetrate the interdigital space of the hand. Although surgical excision is the preferred therapy for interdigital pilonidal sinus, preoperative diagnosis and characterization of pilonidal sinuses may be difficult.

To report the usefulness of ultrasonography in making the diagnosis and evaluating for the size, shape, and internal structure of interdigital pilonidal sinus preoperatively.

We performed ultrasonography (Xario SSA-660A, Toshiba Medical Systems Corporation, Tochigi, Japan) using an 8 MHz linear transducer in B mode.

A round to oval echo-poor area with sharp borders, enhanced dorsal reflection, and lateral echo-free streaks corresponded to the short axial cross section of sinus, and hyperechoic foci within the sinus represented hairs.

Our case highlights the ability to determine key features of sinus tracts and diagnose interdigital pilonidal sinus accurately by ultrasonography. Ultrasonography, in combination with the history and physical examination, increases the diagnostic accuracy of interdigital pilonidal sinus and can help in determining the extent of surgery required to fully remove the interdigital pilonidal sinus.