Pilonidal sinus of external auditory canal as unpredicted lesion: rarest case presentation and review of literatures

Abstract

Abstract Background Pilonidal sinus (PNS) is considered as a benign lesion of hair-bearing areas, particularly at the sacrococcygeal area. It is presented as a hole or tunnel in the skin. It may be filled with fluid or pus resulting in the formation of a cyst or abscess. Although PNS is a well-established lesion in general surgery as well as dermatology specialties by its occurrence at the sacrococcygeal region, but the surprising presentation of PNS is that at ENT specialty by its appearance at the external auditory canal (EAC), which is deemed unpredicted lesion at this particular region. Case presentation Nine years female Libyan child has been presented with a history of persistent offensive bloody stained yellowish discolored left ear otorrhea a few months before her presentation. The local examination including the microscopic examination revealed evidences of a grayish-pinkish pedunculated polypoidal mass raised from the junction of the superior wall with the anterior wall of the EAC, at the site of the junction between the cartilaginous and bony portions of EAC. The temporal bone CT scan revealed evidences of radiolucent soft tissue density mass arising from the wall of the EAC at its anterior-superior junction, with the intact tympanic membrane as well as the middle ear cavity. This was most probably in favor of the suggestion of granulation tissue or aural polyp. The mass was completely excised as one piece from its pedicle and sent for histopathological evaluation, which was in favor of the diagnosis of PNS. Conclusion We consider this case for reporting because of its scarcity and unexpected lesion at EAC. To the best of our knowledge, our case constitutes the second case of the EAC specifically, and the third case of external ear generally reported in the world. Thus, we tried to illustrate this unique and rare EAC lesion concerning how it is clinically as well as pathologically presented. In addition, we tried to review the literatures to elucidate whether this rare lesion has been reported before.